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By W. F. Holbrook

In a previous paper1 a method for the measurement of the comparative desulphurizing power of slags was described and data were presented covering the range of likely slags containing up to 10 per cent MgO. In the present work the range is extended to include slags containing up to 20 per cent MgO, and the effect of temperature on 5 per cent and 15 per cent MgO slags over the range 1475' to 1525' C. is included. The method used was that described in the previous paper except that some of the temperature measurements were made with a noble-metal thermocouple instead of a tungsten-graphite thermocouple. Twelve-gram charges of 0.8 per cent sulphur-metal and 5-gram charges of slag were subjected to heating for 30 min. at a prescribed temperature. The charges were analyzed for sulphur content. For purposes of comparison, desulphurizing power is defined as the ratio of the percentage of sulphur found in the slag to that found in the metal. Six slag and metal charges were made coincidentally in 5/8in. holes in a section of an electrode graphite rod. One slag and metal charge was used as a control by means of which adjustment in the desulphurization value could be made for small variations in temperature and other factors. For convenient presentation of the data, the slags are arranged in groups in each of which one of the four main slag components is constant. Thus, the 15 per cent MgO slags are presented separately from those containing 20 per cent MgO. Slags with Magnesium Oxide Constant 15 Per cent Mg0.—The data on slags containing 15 per cent MgO cover a composition range of 24 to 50 per cent SiO2, 5 to 27 per cent A1203 and 24 to 53 per cent CaO. Variation in composition has been in steps of 2 per cent over much of the area. Because the change in desulphurization power is generally gradual with gradual change in composition, certain sections have been covered in steps of 4 per cent and even

Jan 1, 1938

By David J. Mack

A survey and critical appraisal of published information about Young's modulus was originally made by the writer because of a complete lack of information about this very important quantity in works on. mechanics, physical metallurgy, physics, and other sciences. It was felt that a comprehensive summary of such information about Young's modulus might be of general interest and may suggest new problems or lines of attack on other problems that involve E. Hence this paper has been prepared even though it is only a review, with no new ideas or experimental data. The references are only those used in assembling the paper. No attempt was made to compile a complete bibliography on the subject of Young's modulus. CalculatioX oP YouNg's Modulus from Theoretical or Empirical CoNsidera-tions Many attempts have been made to compute E from theoretical considerations. The earliest calculations were probably those of Tomlenson (1883) and Souther-land (1891), but Fess'enden4',~ made extensive calculations a few years later and arrived at the relationship: £ = 78.TOw(i)* where V is the atomic volume. In 1923, Peczalski, working from the same standpoint but with more information available on atomic structure, arrived at an identical relationship, which he expressed as: where B is a constant of value about 8 . 107, p is density and mis atomic weight; the atomic volume, of course, being ml p. Portevind4 immediately pointcd out that while the equations of Fessenden and Peczalski were true of the common metals, they gave low values for the refractory metals with high moduli (Fig. I). He showed (Fig. 2) that much better concordance was obtained by means of an empirical equation of the form: F- KT" where K is a constant; T the absolute melting point; V, atomic volume, and a and b constants of value approximately I and 2 respectively. This constant K in the Portevin equation is not necessarily the same for all elements, as shown by Thompson. Other equations for E based upon theoretical considerations have been derived by Honda and Yamada49 and Lasareff.50 The most recent calculations of elastic moduli based upon quantum mechanics are probably those of Fuchs He extended the method of Wigner and Seitz for calculating the lattice energy and compressibility of monovalent metals and computed the elastic constants of lithium, 18

Jan 1, 1946

By H. E. Cline, T. H. Alden

A study zvas made of rate-sensitive plastic deformation and superplasticity in alloys of lead and tin. These alloys (lead, PO-19 pct Sn, Sn-38 pct Pb, Sn-2 pct Pb, tin) were extruded, aged at room temperature, or melted and resolidified to produce a variety of ~nicrostrnctures. Flow stress us strain rate data were obtained frorn tension tests for strain rates between 10-6 and 1 min-1. The curve log o .us log £ was S-shaped jor fine-grained materials and approxinzately linear for coarse-grained nzaterials. At constant grain size, the behavior was relatively insensitive to conposition. High rate sensitivity (d log o/d log k) and superplasticity occurred at intermediate strain rates in fine-grained materials and are believed to be associated with a transition with strain rate in the mode of plastic flow. This transition was shifted to higher strain rates with increasing temperataire or decrensing grain size. The high rate rneclzanisrn is presunzed to be slip, while rnetallographic evidence sug-gests that the low rate lnechanism is pain boundary sliding. PEARSON' discovered that extruded eutectic alloys of Pb-Sn and Bi-Sn could be elongated as much as 2000 pct in tension. The ability for stretching decreased with aging time or annealing to increase the grain size. At high strain rates, or if the material was in the cast condition, normal ductility was observed. Following deformation of the extruded Pb-Sn eutectic at low rates, Pearson observed an equiaxed granular structure on an initially flat surface, while rapid straining produced elongated grains. He attributed the large deformation in the extruded alloys to the persistence of extremely small grains to a temperature sufficiently high for inter granular flow. Avery and backofen2 measured the strain rate sensitivity of the flow stress, m = d In old In 6, in the Pb-Sn eutectic and established a correlation between m and the tensile elongation. In the extruded eutectic alloy the strain rate sensitivity was 0.1 to 0.2 at rapid rates and the elongation was small, while at low rates m increased to 0.4 to 0.6 and superplastic elongation was observed. They also noted a grain size effect. In the case of the cast Pb-Sn eutectic the strain rate sensitivity remained at 0.1 over the range of strain rates of their experiment (3 x 10"3 to 2 min-I). These authors suggested that diffusional (Nabarro-Herring) creep was the mechanism by which deformation occurred at low strain rates, while climb-controlled creep occurred at high rates. Two predictions of this model are that, at low strain rates, the strain rate sensitivity approaches 1, i.e., Newtonian viscosity, and that the strain rate at constant stress varies as D/L2, where D is the coefficient of self-diffusion and L the grain size. More recently, a mechanical and microstructural investigation of the dilute superplastic alloy, Sn-5 pct Bi, has been done.3 The results show that the high strain rate sensitivity is associated with a transition with strain rate of the mechanism of plastic flow. At low strain rates, grain boundary sliding and its associated accommodation processes were evident, while at high strain rates quasi-uniform slip was concluded to be the dominant deformation process. The following experiments were performed to extend our knowledge of the phenomena of superplasticity to a larger range of strain rates, compositions, temperatures, and microstructures in the Pb-Sn alloy system. The question of why a cast structure does not exhibit viscous behavior although it appears to have a fine microstructure2 was investigated.

Jan 1, 1968

By H. A. Lequear, J. D. Lubahn

A sudden change from one constant strain rate to another during a tensile test causes an unusual transient in aluminum alloy 61ST. A sudden change from one constant stress to another during a creep test does not produce an unusual transient in this material. A specially devised test shows that the nature of the previous steady-state conditions, which the sudden change disturbs, is one of the factors affecting the transient behavior. Some of the observations may be explained in terms of strain aging. USUALLY a sudden change during a tensile test from one constant strain rate to another causes a small, abrupt vertical shift from one stress-strain curve to another, parallel one. This behavior is apparently characteristic of all metals at very low temperatures and of many metals for wide ranges of temperature. It is illustrated in Fig. 1 for some early data on 61ST tested at — 195oC, and in Fig. 2 for some recent data on copper at room temperature. The greater accuracy of the results of Fig. 2 over previous ones' is due to the equipment shown in Fig. 3. Three levers apply the bulk of the load, while the changes in the small remainder load are indicated sensitively by a low capacity load scale. Refs. 2 and 3 describe the recording equipment. A test like those in Figs. 1 and 2 provides the information necessary to determine the rate sensitizrity, n,4 of the metal. ( a log s ) ? log s n = ------------------------ ----------------------------= ( a logs e, ? log e logS2-logS1 log S2/S1 log i2 — log e1 log e2/e1 where S equals stress: e is logarithmic strain or natural logarithm of (final gage length/initial gage length);" i is strain rate or de/dt: and n is rate sensitivity, rate of change of log stress with log strain rate at a given strain, or (a log S/a log i),. Normally, the rate sensitivity, n, is positive, which means that an increase in stress causes an increase in rate. However, certain exceptions, attributed to strain aging,5 have been observed. Fig. 2 indicates how rate sensitivity values are derived from the measurements. Table I summarizes the rate sensitivity values derivable from Fig. 1. In contrast to the behavior of copper in Fig. 2, the aluminum alloy 61ST, which strain ages when tested near room temperature, exhibits an unusual transient when the strain rate is suddenly changed,' as shown in Fig. 4. Initially, there is a comparatively sudden vertical shift of the stress-strain curve in a direction corresponding to the rate change, but then the curve gradually shifts back again. The initial shift is not as sudden as might be expected, because the testing machine is unable to achieve the impressed rate change instantaneously, as illustrated in Fig. 2. The behavior shown in Fig. 4 will be referred to as a tensile transient, the word tensile implying that the behavior was observed in a tension type of test. The corresponding test, where the strain rate is maintained constant except for the sudden change, will be called a tensile transient test. A creep transient, by contrast, will be defined as a temporarily abnormal behavior in a creep transient test, where there is a sudden change from one constant load to another.' In Fig. 4, a naive look at the gradually decreasing and then increasing load after a sudden rate incre-

Jan 1, 1957

By WILLETT G. MILLERS

GENERAL RECEPTION COMMITTEE.-Willett G. Miller, Chairman; F. G. B. Alan, Hon. Frank Cochrane, Eugene Coste, Thomas W. Gibson, Cyril W. Knight, J. C. Murray, 0. N. Scott, Alan Sullivan, J. B. Tyrrell, J. W. Wells, A. B. Willis. COBALT RECEPTION COMMITTEE.-Arthur A. Cole, Chairman; Will. Ask with, R. W. Brigstocke, Robt. Bryce, Fred Coombs, M. I. Culbert, I. R. Drummond, J. W. Evans, A. Ferland, F. N. Flynn, E. L. Fraleck, S. R. Heakes, Joseph Houston, D. L. Jemmett, I. R. Jones, Major Leckie, Capt. Jack Leckie, R. W. Leonard, W. H. Linney, Alexander Longwell, Frank Loring, Murdock McLeod, John Martin, D. B. Rochester, W. E. Running. COBALT RECEPTION COMMITTEE (Ladies).-Mrs. A. A. Cole, Mrs. A. Edwards, Mrs. R. Jennings, Mrs. S. H. Logan, Mrs. A. Longwell, Mrs. H. F. Marsh, Mrs. J. Smith. SUDBURY LOCAL COMMITTEE.-Mayor L. O'Connor, Chairman; S. Fournier, Secretary; A. H. Beath, W. J. Bell, F. B. Bennett, D. M. Brodie, J. S. Buchanan, F. C. Busby, Wm. Chalmers, R. Dorsett, W. A. Evans, John Frawley, J. S. Gill, A. B. Gordon, J. G. Henry, T. N. Kilpatrick, Major Leckie, Chas. McCrea, John McLeod, Wm. McVittie, R. Martin, R. S. Mitchell, J. H. Morin, J. A. Orr, James Purvis (President Board of Trade), C. R. Reid, Major Smith, W. W. Stull, J. F. Templeton, S. E. Wright. The first session, held in the Banquet Hall of the King Edward Hotel, was called to order Tuesday, July 23, 1907, at 2.30 p.m., President John Hays Hammond presiding. Prof. Willett G. Miller, chairman of the General Committee, introduced Alderman J. J. Graham, who, in behalf of the City of Toronto, extended a hearty welcome to the members and guests of the Institute. To this welcome, President Hammond replied in a few well-chosen and hearty remarks. In the hall in which the session was held there was exhibited a fine, full-length, life-size portrait of Dr. Rossiter W. Raymond, in 1871 Vice-President and acting President, in 1872, 1873 and 1874 the elected President, in 1876 and 1877 Vice-President, in 1883, by appointment of the Council, and for the last 24 years by annual election, Secretary, of the Institute. Dr. James Douglas, of New York, N. Y., on behalf of numer-

Sep 1, 1907

By F. W. Bloecher

DETERMINATION of the surface area of finely divided minerals is of interest to mineral engineers engaged in flotation, comminution, and de-watering studies. In the industrial minerals field, many materials are classified as to fineness according to their specific surface (surface area per unit weight). A method of surface area determination has been tested and used in the Richards Mineral Engineering Laboratories at M.I.T. It involves low temperature krypton adsorption measurements using the technique described by Beebe.' During the past fifteen years a number of new surface measurement techniques have been developed. Those that are broadly applicable to materials dealt with by mineral engineers include the permeability method in which a gas or liquid is passed through the sample, and the low temperature gas adsorption methods first described by Brunauer, Emmett, and Teller."" Efforts to make surface determinations from size distribution curves have long been attempted"."." but because of the uncertainty of sub-sieve size distribution and inaccuracies in screen analyses, the method is at best only a rough approximation. The most widely used gas adsorption method utilizes nitrogen gas." Nitrogen adsorption, however, is not particularly suited as a tool for most mineral engineers because the method is not applicable for surface determinations on coarse materials, that is, materials coarser than approximately 150 to 200-mesh. Other gases have been used in mineral engineering studies, particularly ethane."' lo The use of ethane gas, however, involves .a technique that is too sensitive for most mineral engineering work. The permeability method of surface area determination has the disadvantage of not being sensitive enough to detect the surface represented by minute cracks, the so-called internal surface of a particle. The low temperature krypton adsorption method described by Beebe1 utilizes apparatus and techniques that are essentially the same as those used in the ethane adsorption method."1° The surface area is calculated by the B.E.T. method."-' The krypton adsorption technique is particularly suited to the needs of the mineral engineer because: (1) The method can be used for making surface area measurements of rather coarse materials (35 to 48-mesh), as well as extremely fine materials, such as clays or colloidal slimes with specific surface that might be as high as 20 to 30 mb er g. (2) The use of krypton gas offers the advantage of low saturation pressures (2-3 mm) at the conveniently obtained liquid nitrogen temperature. Therefore the krypton vacuum system need not be designed to measure or withstand internal gas, pressures above one atmosphere as is the case with the nitrogen gas method. (3) The krypton technique offers the safety feature of employing liquid nitrogen, as contrasted to the ethane technique in which liquid oxygen is required. Furthermore, ethane vapor pressure at liquid oxygen temperatures is low (about 10 microns), and a high sensitivity McLeod gage is required for pressure readings. (4) The measurement technique with krypton gas is much simpler and faster, and the apparatus is less elaborate than that required with either nitrogen or ethane gases. Apparatus A krypton surface measurement apparatus like that used at M.I.T. is shown in Fig. 1. It is constructed of pyrex glass. A vacuum is maintained by two mercury diffusion pumps in series backed by a mechanical vacuum pump."' The vacuum thermocouple gage is used for checking the vacuum within the system. This type of gage is quite sensitive down to a pressure of 1 micron of mercury," but may be used to indicate pressures much lower than that

Jan 1, 1952

By B. S. Gottfried

This paper is concerned with possible transport mechanisms which occur during segregated burning (i.e., burning in an oil reservoir in which the oil-bearing formation is overlain by a "clean" porous zone containing only gas). ,Two analytical models are presented. In the first, burning is assumed to occur at the gas-oil interface, and the dominant mechanism is taken to be the rate at which oxygen diffuses to the interface. The second model assumes that combustion occurs within the clean zone, with the dominant mechanism being the mechanism of fuel deposition from the oil-bearing formation to the clean zone. ,Comparison of the results of the analyses with limited experimental data indicates that the latter mechanism is much more plausible. Both models are idealized representations of the actual process and are somewhat conjectural, however, owing to the lack of more definitive laboratory or field data. INTRODUCTION In recent years there has been considerable theoretical and experimental research directed toward understanding the recovery of crude oil by underground combustion. Although two different recovery schemes have been proposed, known as forward and reverse combustion, it is only forward combustion that shows promise of becoming a practical recovery technique.17 Most of the analyses of the forward combustion process have considered it to be pistonlike; i.e., oil is displaced by a vertical combustion zone which, with its ensuing gases, pushes die oil forward as the flame front is propagated through the reservoir.l-8,ll,l2,14-16 However, information gained in field pilot studies indicates that, at least to a certain extent, forward combustion proceeds in a segregated manner in oil reservoirs.10 An ideal segregated system is one in which the oil-bearing formation is overlain by a "clean" porous zone containing only gas. The location of the combustion zone in such a system is not immediately evident, although combustion is believed to occur either at the gas-oil interface or within the clean zone. In either case, the combustion zone may be horizontal and it moves in parallel rather than in series with the produced oil. The purpose of this paper is to explore the likely mechanisms by which segregated burning can occur, and to determine the sensitivity of the resulting models to changes in various physical parameters. Two governing mechanisms are considered: the case of a horizontal combustion zone at the gas-oil interface with the rate of combustion governed by the rate at which oxygen diffuses to the interface, and the case of combustion within the clean zone with the combustion process controlled by the transport of fuel from the oil-bearing formation to the clean zone. Both models are somewhat hypothetical and involve considerable simplification of the actual process. However, the results allow some preliminary understanding of segregated burning which is useful in the absence of more definitive laboratory or field pilot data.

Jan 1, 1967

By J. D. Clark

ONE'S lifetime does not usually offer the oppor-tunity to observe and be a part of the commercial development of an entirely new material. Petalite has been known for over a century, but at first it was presumed rare. However, it was found to be so abundant that it has become a new and extremely useful industrial tool. Mineralogy Petalite is a lithium-aluminum-silicate mineral. It was from petalite that J. A. Arfwedson first discovered lithium in 1818. The theoretical composition of Li2O • A12O8 • 8SiO2 is equivalent to 78.4 pct silica, 16.7 pct alumina and 4.9 pct lithia. The mineral in its known commercial occurrence is colorless to white and rarely gray, transluscent and rarely transparent. It is brittle, has a vitreous luster, and occurs usually in cleavable masses (fig. 1). It is classified as a di-silicate, but is similar in composition to the metasilicate spodumene, Li2O.-Al2O8-4SiO2 (table I). However, their specific gravities are quite different (3.13 to 3.20 for spodumene, 2.39 to 2.46 for petalite). Occurrence Petalite specimens have been reported in many localities; however, there are only three known countries having occurrences of commercial significance. The classic locality is Sweden's Utö Mines, which, although reportedly still containing considerable petalite, have been closed and are not expected to be operated in the near future. At Varuträsk, in northern Sweden, petalite carrying 4 pct lithium oxide is the main ore. In 1946 there was reported about 1000 tons on hand. However, the iron content was 0.60 pet too high for other than chemical use. Petalite has been reported in western Australia. At the Cottesloe mine, where small quantities have been reported available, it is produced in conjunction with feldspar. Petalite occurs in considerable quantity in the feldspar quarry at Londonderry, and it was estimated1 in 1943 that over 3700 tons might be available. The petalite in South West Africa was first discovered by F. J. Jooste, a lawyer by profession, in 1938. The following year he discovered a much larger deposit, and in 1948 another important discovery was made. These deposits occur near Kari-bib and constitute the only known commercial deposits. Their full extent has not yet been determined, but huge massive blocks of petalite of the purest grade, running into many thousands of tons, can be seen in all these deposits. To date, 60,000 tons of high grade, low iron containing ore has been blocked out in the major bodies. Mining for years to come will be confined to simple quarrying. Selection from accessory minerals has proved

Jan 1, 1951

By J. D. Clark

ONE'S lifetime does not usually offer the oppor-tunity to observe and be a part of the commercial development of an entirely new material. Petalite has been known for over a century, but at first it was presumed rare. However, it was found to be so abundant that it has become a new and extremely useful industrial tool. Mineralogy Petalite is a lithium-aluminum-silicate mineral. It was from petalite that J. A. Arfwedson first discovered lithium in 1818. The theoretical composition of Li2O • A12O8 • 8SiO2 is equivalent to 78.4 pct silica, 16.7 pct alumina and 4.9 pct lithia. The mineral in its known commercial occurrence is colorless to white and rarely gray, transluscent and rarely transparent. It is brittle, has a vitreous luster, and occurs usually in cleavable masses (fig. 1). It is classified as a di-silicate, but is similar in composition to the metasilicate spodumene, Li2O.-Al2O8-4SiO2 (table I). However, their specific gravities are quite different (3.13 to 3.20 for spodumene, 2.39 to 2.46 for petalite). Occurrence Petalite specimens have been reported in many localities; however, there are only three known countries having occurrences of commercial significance. The classic locality is Sweden's Utö Mines, which, although reportedly still containing considerable petalite, have been closed and are not expected to be operated in the near future. At Varuträsk, in northern Sweden, petalite carrying 4 pct lithium oxide is the main ore. In 1946 there was reported about 1000 tons on hand. However, the iron content was 0.60 pet too high for other than chemical use. Petalite has been reported in western Australia. At the Cottesloe mine, where small quantities have been reported available, it is produced in conjunction with feldspar. Petalite occurs in considerable quantity in the feldspar quarry at Londonderry, and it was estimated1 in 1943 that over 3700 tons might be available. The petalite in South West Africa was first discovered by F. J. Jooste, a lawyer by profession, in 1938. The following year he discovered a much larger deposit, and in 1948 another important discovery was made. These deposits occur near Kari-bib and constitute the only known commercial deposits. Their full extent has not yet been determined, but huge massive blocks of petalite of the purest grade, running into many thousands of tons, can be seen in all these deposits. To date, 60,000 tons of high grade, low iron containing ore has been blocked out in the major bodies. Mining for years to come will be confined to simple quarrying. Selection from accessory minerals has proved

Jan 1, 1951

By Charles L. Harness

STRONTIUM is an essential constituent of celestite (strontium sulphate), of the rarer strontianite (strontium carbonate), and of a few very rare minerals. Celestite is the chief ore but strontianite is more valued except for making the purest strontium salts, because of its ease of processing. The public knows strontium mainly as the source of the red flame in fireworks but it has many other uses. PROPERTIES The celestite of commerce is a massive mineral of varying texture: coarsely crystalline, fibrous, bladed, very fine grained or earthy. The color varies greatly with the nature of the impurities but the purer specimens are light blue (Latin, caelum, sky) or white. The strontianite of commerce is a massive mineral, more or less coarsely crystalline. The color varies with the impurities. Distinctive characteristics are effervescence with acids, density (3.68 to 3.71), and crimson strontium flame. A typical British celestite before World War II analyzed: SrSO4, 96.55 pct; SrCO3, 0.17; BaSO4, 0.25; CaSO4, 0.54; MgCO3, 0.15; R20,, 0.90; Si02, 1.38.10 A German strontianite analyzed: SrCO3, 90.9 pct; CaCO3, 7.5; BaCO3, 0.1; Fe2O3, 0.05; A1203, 0.1; SiO2, 0.04; S, 0.1; P, 0.005.10 ORIGIN AND MODE OF OCCURRENCE According to Clarke,9 strontia forms about 0.02 pct of the crust of the earth and is present in most igneous rocks, but in smaller quantities than barium. Under certain conditions, large masses of celestite are deposited from sea water with anhydrite. The presence of large amounts of celestite in some saline deposits and its absence in others suggests that the deposition of celestite depends on whether certain as yet undetermined concentrations of sulphate and chloride ions are reached in the brines. The most extensive of these sedimentary deposits are those of the Keuper (Triassic) in England, of the Zechstein (Permian) in Germany, and of various Cretaceous formations in Texas, Arkansas, and Utah. Of the deposits of southeastern California and western Arizona,

Jan 1, 1949

By T. Watanabe, S. Karashima, H. Oikawa

Creep tests of a! iron and its solid-solution Fe-Mo, Fe-Co, and Fe-Si alloys with bcc structure were conducted under constant stresses in ferromagnetic and paramagnetic temperature regions above 0.5T,(T, is the absolute melting temperature). It was found their high-temperature creep behavior changed in the vicinity of the magnetic transformation temperature, that is Curie temperature, TC. In the ferromagnetic region below the steady-state creep rates were lower than those expected from the extrapolation of the data in the paramagnetic region, the amount of decrease being affected by solute addition. Also, activation energies for steady-state creep were different in the two temperature regions. The observed changes were concluded to be due to the effect of ferromagnetism on diffusion. It is well-known that plastic deformation of metals and alloys in the temperature region where mobility of atoms becomes high enough is controlled by atomic diffusion." Many experimental results394 on fcc and hcp materials have been reported to confirm this view. In bcc metals and alloys, not much basic investigation of creep deformation has been performed. In particular, experimental work on iron5-&apos; and its alloys, covering a quite wide temperature range is extremely scarce. On the other hand, the effect of ferromagnetism on diffusion has recently been demonstrated in a iron and its alloys;&apos; it has been made clear that diffusion rates in ferromagnetic temperatur~e region are significantly lower than those expected from diffusion measurement in the paramagnetic region. Therefore, it is concluded that the magnetic effect influences the high-temperature creep behavior in a! iron and in its alloys. The present authors have conducted creep experiments on a iron and its solid-solution alloys over a very wide temperature range, and have demonstrated the magnetic effect. A part of the result has already been reported elsewhere.26 In this paper, the experimental results will be described in detail. While the manuscript was in preparation, a similar magnetic effect on creep deformation of a iron was reported by Ishida . Though their experiments covered an extremely wide temperature range, the creep stresses varied from several thousand psi to several ten thousand psi with decreasing temperature. Consequently, it may be said that there remain some questions concerning their results. I) EXPERIMENTAL PROCEDURE The materials used in the experiments were pure iron and its alloys; they were prepared by vacuum melting (10"" mm Hg) electrolytic iron (99.9 pct), molybdenum powder (99.9 pct), ultrapure silicon, and cobalt pellet (99.5 pct) in alumina crucibles. The ingots were hot-forged to plates 10 mm thick and 50 mm wide, and then were hot-rolled at about 700°C into sheets 1 mm thick. Creep specimens, 5 mm in width and 15 mm in gage length, were machined from the sheets. They were annealed at temperatures which were well above their respective recrystallization temperatures. The chemical compositions of the metal and alloys are shown in Table I together with their heat treatments. High-temperature creep tests by the use of a lever-type creep testing machine were carried out in argon atmosphere under constant tensile stress. In order to keep &eep stress constant within about *0.5 pct, stress change due to specimen elongation was compensated by tensile force of a stainless-steel bellows which was inserted between the loading lever and lower specimen grip with the assumptions of a linear relationship between change in cross section and strain and uniform strain along the section. Beyond the limit of compensation by the bellows, small amounts of load were removed after appropriate strains. The testing temperatures were maintained to within i2"C of the reported values. Creep deformation was auto-graphically recorded at the upper (moving) specimen grip using a linear differential transformer which was held by a stainless-steel rod mechanically connected to the lower specimen grip. It was also directly measured with a dial-gage reading to -& mm. 11) EXPERIMENTAL RESULTS AND DISCUSSION 1) Creep Curves of a Iron and Its Alloys. Creep curves of a! iron, Fe-Si, Fe-Co, and Fe-Mo (<2 at. pct Mo) alloys usually consisted of three stages, that is transient (primary), steady-state (secondary), and accelerating (tertiary) stages. An example is illustrated in Fig. 1 for a! iron. However, in Fe-Mo alloys with more than 2 at. pct Mo, an inverse transient creepZ8 was observed as indicated in Fig. 2. The inverse behavior, which varied with the amount of molybdenum, may be due to the substructure* in the annealed specimen as was sug-

Jan 1, 1969

By J. L. Tomlinson, B. D. Lichter

Electrical resistivities 01 liquid Cd-Bi, Cd-Sn, Cd-Pb, In-Bi, and Sn-Bi alloys were measured using an electrodeless technique. The resistivities ranged from 50 to 160 microhm -cm, temperature dependences were positive, and no sharp peaks in the composition dependence of the resistivity were observed. On the basis of these observations, it was concluded that the alloys are typical metallic liquids. The electron con-cent9,ation was calculated from the measured resis-tizlity and available thermodynamic data using a model which attributes electrical resistivity to scattering by density and composition flzcctuations. A correla-tion was shown between the departure of the electron concentration from a linear combination of the pure component valences and the value of the excess integral molar free energy. Calculation of the temperature dependence of the electrical resistivity showed a need for more detailed thermodynamic data in these systems and led to suggestions for improvement in the concept of residual resistivity in the fluctuation scattering model. THE electrical resistivity of liquid metals provides information regarding interatomic interactions and their effects upon structure. In this experiment an electrodeless technique was used to measure the electrical resistivities of liquid alloys of Cd-Bi, Cd-Sn, Cd-Pb, In-Bi, and Sn-Bi, and the results were used with thermodynamic data to calculate a parameter which reflects the tendency toward localization of electrons due to compositional ordering. It was found that the resistivities of these alloys are generally metallic in magnitude and temperature dependence. The electrical and thermodynamic properties are discussed in terms of the fluctuation scattering model&apos;22 which supposes that the electrical resistivity arises from scattering due to a static average structure and departures from the average due to fluctuations in density and composition. Further, this model is compared with the pseudopotential scattering model of Ziman et al.3-5 EXPERIMENTAL PROCEDURES Alloy samples were prepared from 99.999 pct pure elements obtained from American Smelting and Refining Company (except tin which was obtained from Consolidated Smelting and Refining Company.) J. L. TOMLINSON, Member AIME, formerly Research Assistant Division of Metallurgical Engineering, University of Washington, Seattle, Wash., is now Physicist, Naval Weapons Center, Corona Laboratories, Corona, Calif. 0. D. LICHTER, Member AIME, is Associate Professor of Materials Science, Department of Materials Science and Engineering, Vanderbilt University, Nashville, Tenn. This work is based on a portion of a thesis submitted by J. L. TOMLINSON to the University of Washington in partial fulfillment of the requirements for the Ph.D. in Metallurgy, 1967. Manuscript submitted May 31, 1968. EMD Weighed portions were sealed inside evacuated silica capsules, melted, and homogenized before the resistivity was measured. The resistivity of a liquid alloy was measured by placing the sample inside a solenoid and noting the change in Q. According to the method of Nyburg and ~ur~ess,~ the resistivity of a cylindrical sample may be determined from the change in resistance of a solenoid measured with a Q meter as T7--5--W =R7JT^ =&apos;Kc-lm(Y) [1] where L, R, and Q = wL/R are the inductance, series resistance, and Q of the solenoid. The subscript s refers to the solenoid with the sample inside; the subscript 0 refers to the empty solenoid. Kc is the ratio of the sample volume to coil volume and y = 2 [bei&apos;0(br)-j ber&apos;o(br)~\ br\_bero(br) +j bei0 (br) expressed with Kelvin functions which are the real and imaginary parts of Bessel functions of the first kind with arguments multiplied by (j)3&apos;2. The argument of the function Y is hr where r is the sample radius and b2 = po~/p, i.e., the permeability of free space times 271 times the frequency divided by the resistivity in rationalized MKS units. Since Eq. [I] cannot be solved explicitly for p, values of Kc. lm(Y) were tabulated at increments of 0.1 in the argument by. A measurement of Q, and Q, determined a value of Kc . lm (Y) and the corresponding value of br could be read from the table. From the known r, uo,, and w, the resistivity, p, was determined. The change in Q was measured after letting the encapsulated Sample reach equilibrium inside a copper wire solenoid. The solenoid was contained in an evacuated vycor tube in order to retard oxidation of the copper while operating at high temperatures and heated inside a 5-sec-tion nichrome tube furnace capable of obtaining 900°C. Temperature was determined with two chromel-alumel thermocouples, one in contact with the solenoid 30 mm above the top of the sample and the other inserted in an axial well at the other end of the solenoid and secured with cement so that the junction was 2 mm below the bottom of the sample. Temperature readings were taken with respect to an ice water bath junction, and the voltage could be estimated to the nearest thousandth of a millivolt. The lower thermocouple was calibrated by observing its voltage and the Q of the coil as the temperature passed through the melting points of samples of indium and tellurium. The upper thermocouple reading was systematically different from the lower thermocouple reflecting the temperature difference due to a displacement of 60 mm axially and 6 mm radially. Calculations show that the gradient over the sample was less than 2 deg. Q was measured by reading a voltage related to Q from a Boonton 260A Q meter with a Hewlett Packard

Jan 1, 1970

By Robert S. Moehlman

Is recent years, exploration and development by diamond drilling has become a popular attack on the problem of finding new ore shoots and developing extensions of known shoots. Diamond drilling has been used in recent years in extensive sampling of disseminated copper deposits, in preference to churn drilling. At the Harvard gold mine, near Jamestown, California, Philip R. Bradley, Jr., general superintendent, reports that: "The Harvard work was a singular example of the reliance that can be placed on diamond drilling in evaluating an ore body." Drilling at the Harvard mine will be discussed in a subsequent section of the paper. So popular has diamond drilling become, indeed, that many who have had slight experience with drilling are inclined to regard it as a cheap cure-all. This paper proposes to show some of the limitations on the application of drilling and some of the steps that should be followed in drilling programs to obtain reliable results. Cost oF Drilling Drilling has the advantage, over shaft sinking and drifting, of lower cost and greater speed. As compared with churn drilling, the advantage of bringing up a coherent sample instead of fine cuttings for a sample is obvious. Diamond drilling is generally more expensive, however, and more engineering effort is required in combining the average of core and sludge samples. Exploration of drift walls by hammer drills to a depth of less than 30 ft. is generally cheaper than diamond drilling, but beyond this depth the diamond drill is cheaper and more efficient. The principal factor in determining cost of drilling is the character of the ground drilled. Broken ground with many fissures is most expensive to drill. Hard ground is less of a problem with diamond drills than with ordinary machine drills. Hardness or softness affects only the speed of drilling. Caving, easily washed, sandy or clayey ground requires continual cementing and casing, which is the greatest cost problem. Thus, soft, incompetent ground is more costly to drill than hard, massive ground. Cost of drilling per foot in good to fair ground varies from less than $I per foot, achieved in some districts in Ontario, the Mother Lode, and Missouri, to $5 per foot in many western states. In bad drilling ground, costs may range from $5 to $15 or more per foot, thus approaching the cost of drifting. Other factors that increase the cost per foot are: I. Short total length of hole drilled, so that the cost of moving in crews and equipment must be spread over a relatively few feet. 2. Cost of drilling per foot increases with depth beyond about 500 ft.. as more time is consumed in pulling rods&apos; 3. Cost of preparing drilling stations, getting air underground to stations? etc&apos; 4. Inaccessibility and lack of water on the job make for higher costs.

Jan 1, 1946

By Potts N. L., Eilerts C. K., Summer E. F.

The second-order, nonlinear, partial- dillerential equation representing the transient radial flow of gas - condensate fluids in reservoirs has been integmted by using finite -dillerence equations and electronic computers. Effect was given to pressure -dependent permeability, viscosity, and compressibility and to distance-dependent permeability. The influence of a second-degree velocity term in the Darcy equation was investigated. Implicit methods were used and practical, convergent solutions were obtained with material balance to less than 6 x 10-4 for recovery of one- hall the reserve at constant flow rate. Integration results provide the productive period of a reservoir for a given constant rate and the fraction of the fluid initially in place that can be recovered in that period. The properties of a lean and a rich fluid are represented in a set of integrations designed to demonstrate the effect of different constant-recovery rates and significant variables emphasized one at a time. INTRODUCTION A method is needed for computing the availability or reserve of a gas in a formation, making use of all technical and engineering information that is pertinent. As a step in this direction, a program for computing transient linear flow1 was developed that utilizes principles of earlier finite-difference computing for a similar purpose2-4 and gives effect to significant pressure- and distance-dependent properties of reservoirs and their contents. The present paper pertains to transient, radial flow of gas-condensate fluids. In the partial-differential equation of flow, effect is given to the variables viscosity and compressibility,5 and also to permeability. Included in the study is the quadratic form of the Darcy equation of flow that has been the subject of field tests6 and that has been applied to a gas with constant properties in transient flow computing. 7 Inclusion in the differential equation of variable coefficients to represent properties greatly complicates the higher derivatives of the equation. Because it was impractical to make a required improvement in certain of the finite-difference derivatives by Taylor-series expansion, five-term derivatives were used in the implicit computing. Related methods were developed that can improve general facility in manipulating finite-difference equations. BASIC EQUATIONS PARTIAL DIFFERENTIAL EQUATION The basic partial differential equation for transient radial flow in the direction of decreasing radius is l_ a(vpr) _? .......(1) r gr at where r = radius, L v = apparent velocity aIong radius, L/t p = density, M/L3 t = time, t Ø = porosity, dimensionless. In this equation, only the porosity is regarded constant. The density is where p = pressure, m/Lt2 M = molecular weight of fluid, m T = constant temperature of fluid, T z(p) = pressure-dependent compressibility factor, dimensionless R = gas Constant, mL2/t2t. The physical boundary of the reservoir is at re, and the producing boundary is defined to be at tq with rq = re /200. By definition,

Jan 1, 1966

By R. B. Russell

SINCE Cahn&apos;s¹ paper on plastic deformation in orthorhombic (a) uranium an increasing amount of work is to be expected on orientation of single crystals and preferred orientation in this metal. It would seem desirable to have a table of angles between crystallographic planes (hkl) and (HKL). Table I shows these angles as distances from (loo), (0l0), and (00l), and in Fig. 1 as a standard (001) stereographic projection. Only the locations of poles whose diffracting planes produce Cu Ka reflections up to 0 = 70.5" (i.e. (154) ) are given." The relative reflection of these planes are represented by circle diameters. It is hoped that the projection may also be used in making inverse pole figures, originally suggested by Harris.&apos; Values of 4 were calculated from the expression hH kK 1L cos = hH/a²+kK/b²-lL/c² where the lattice parameters a, b, c, and the spac-ings d were taken from the work of Jacob and Warren." (They report a = 2.852 kX (2.8578 A), b = 5.865 kX (5.8768 A), c = 4.945 kX (4.9550 A).) The parameters reported by them may be subject to revision,4,5 accordingly the interplanar angles are listed to only the nearest tenth of a degree. References ¹R. W. Cahn: Acta Metallurgica (1953) 1, p. 49. ¹G. B. Harris: Philosophical Magazine (1952) 43, p. 113. 3C. W. Jacob and B. E. Warren: Journal ACS (1937) 59, p. 2588. 4J. S. Lukesh: Acta Crystallographica (1949) 2, p. 420. ³ J. Thewlis: Nature (1951) 168, p. 198.

Jan 1, 1954

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York L. W. FRANCIS, Chairman. WILLARD S. MORSE, Vice-Chairman. . THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. P. A. MOSMAN, Treasurer. LOUIS D. HUNTOON, Boston HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. AUGUSTUS H. EUSTIS, Secretary-Treasurer, 131 State St., Boston, Mass. TIMOTHY W. SPRAGUE, HENRY A. WENTWORTH. Columbia F. A. THOMSON, Chairman. GEORGE W. RODDEWIG, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. R. S. McCAFFERY, S. H. RICHARDSON.

Jan 6, 1914

By G. N. Goldberg, Robert A. Rapp

The steady-state kinetics and microstructures of simultaneous internal oxidation and external scale formation were investigated for the oxidation of Cb-Zr and Ch-Zr-Re alloys in pure oxygen at 1000°C. For each binary alloy, a constant rate of scale formation was observed at steady state; the internal oxidatton zone reached a steady-state, time-independent thickness. The dependence of the scaling rate on zirconium content exhibited a maximum at a low zirconium colttent; more concentrated alloys oxidized at a slower rate than pure columbium. This composition dependence of the scaling rate may be partially attributed to the effect of the internal oxidation process as an intenla1 sink for oxygen, with the formation of voluminous, and relatively impermeable ZrO2 precipitates. However, the morphologies of the ZrO2 internal oxide precipitates also affected the scaling rate. The internal oxide precipitates were distributed uniformly in the external scale. The steady-state thicknesses of the internal oxidation zones were not in agreement with those predicted theoretically from an idealized simple model. However, in this particular alloy systen1 the ideal model is not satisfied experitmentally. For ternary Cb- Zr - Re alloys with Nr10e = 0.02 or 0.05, the steady-state thicknesses of the internal oxidation zones were less than those for the corresponding binary Cb-Zr alloys. For ternary alloys with NRe(0) - 0.05, a more adherent and much less porous external scale was formed, and a reduction in the kinetics of scale formation was observed. A number of authors&apos;-7 have reported linear oxidation kinetics for the reaction of pure columbium at 1000°C in air or in oxygen of about 1 atm pressure. A thin and tightly adherent oxide layer is found at the metal/oxide interface beneath a porous external layer of scale. Although the suboxides CbO and CbO2 represent thermodynamically stable phases at 100O°C, generally only Cb2O5* is identified as a reaction product in quenched specimens. Studies at 1000°C at lower oxygen pressures8,10 (Po2 - 10-4 Torr) show that both CbO and CbO2 do form and that CbO2 is a protective oxide. The growth of CbO2 results in parabolic kinetics until Cb2O5 is nucleated and grows. Apparently because of the large volume change associated with its formation, Cb2O5 is porous and does not serve as a diffusion barrier; linear kinetics prevail after the surface is covered with Cb2o5. On the basis of these observations, several authors5,9,10 have suggested that the linear oxidation of pure columbium at 1000°C in air or oxygen of 1 atm is limited by a Loriers-type mechanism,11 whereby the total rate or reaction is controlled by ionic diffusion through a thin layer of CbO2 which is maintained at a constant thickness throughout the linear oxidation. However, the concept of a Loriers model for a three-phase CbOlCbO2 Cb2O5 scale, with the only oxygen activity gradient across the NbO2 phase, is not self-consistent. Further, the suboxides CbO and CbO2 were not observed in the high-temperature X-ray diffraction study of columbium oxidation by Goldschmidt.8 From investigations in which the large PO2, dependence of the linear scaling rate was demonstrated, the importance of an oxygen adsorption or dissolution step has been suggested.4,5,7,10,12 Thus the mechanism for the linear oxidation of pure columbium remains quite controversial. Since further insight into the oxidation mechanism of pure columbium is not provided by this investigation, the authors wish to emphasize at the outset that their experimental results are not interpreted in terms of a particular rate controlling step for the oxidation of pure columbium. Previous investigations13-18 of the oxidation of Cb-Zr solid-solution alloys in air or oxygen at 1000°C suggest a remarkable dependence upon zirconium content. For an alloy of bulk zirconium mole fraction, N2r(0) equal to 0.05 or 0.10, the oxygen uptake is reported to be as high as four times greater than that for pure columbium;13,14 for alloys with NZr(0) 0.05 or 0.10 the oxygen uptake is reported to decrease with increasing NZr(0); to a minimum uptake of about one quarter that for pure columbium at NZr(0): = 0.50.13-15Since zirconium forms a more stable oxide (ZrO2) than the lowest columbium oxide (CbO), and since columbium exhibits a high solubility19,20 and diffusivity21,23 for oxygen, the internal oxidation of the zirconium component to ZrO2 is expected at a reaction front ahead of the advancing metal/scale interface. The external scale is then formed at the metal/scale interface by the inward migration of oxygen through the scale, probably through a series combination of molecular and ionic diffusion. Internal oxidation in conjunction with external scale formation has been investigated by Maak24 for the oxidation of dilute Cu-Be alloys in pure oxygen at 850°C. For cu-Be and many other binary alloys,24-27 very small, essentially uniaxial internal oxide particles are formed in the most dilute compositions; for somewhat more concentrated alloys. the internal oxide particles precipitate as platelets or needles. From pertinent solutions to the diffusion equation, Maak28

Jan 1, 1967

By H. M. Dess, S. R. Bolin

A modifiedl Czochralski technique has been utilized to grow single crystals of YVO, pure or doped with europium or neodymium, from 1 to 2 in. long and 4 to 1/2 in. in dianz. An oxyhydrog-en gas-fired furftace zuas used in this ulork, and melts were contained in iridium crucibles. Successful application of the Czochralski ~vzethod was found to depend upon atmosphere control to prevent crusting and to limit melt decomposition, the establishment of symmetrical thermal gradients in the melt to obtain stable growth, and the selection of high-quality single-crystal seeds to prevent propagation of misorientations during growth and subsequent catastrophic cracking. The suitability of YVO4 as a host for laser-active trivalent rare earth ions has long been recognized. However, the problems associated with the growth of sufficiently large, good-quality single crystals have, until quite recently, seriously hindered satisfactory evaluation of the laser potentialities of this material. Both flux growth and Czochralski growth techniques were investigated at an early stage of interest in YVO,. The former method proved incapable of yielding crystals large enough for practical use,ly2 and the latter was beset with difficulties which took some considerable time to understand and overcome. Recently, however, the Czochralski growth process for YVO, has been improved along separate but similar lines of development by groups working independently in the Crystal Products Department of Union Carbide&apos;s Electronics Division and Bell Telephone Laboratories3 so that now good-quality single crystals of satisfactory size can be produced on a routine basis. Stimulated emission from a neodymium-doped YVO4 crystal grown by the Crystal Products Department of Union Carbide was obtained by O&apos;connor4 of MIT, Lincoln Labs. An oxyhydrogen gas-fired furnace was used in this work, Fig. 1, and melts were contained in iridium crucibles. The starting material was 99.9 to 99.99 pct pure YVO4 powder purchased from the Chemical and Metallurgical Division of the Sylvania Electric Products Co. Typical impurity levels, determined by spectrographic analyses, were as follows: Si, 50 to 500 ppm Al, Fe, Mg, 5 to 50 ppm Ni, Pb, Mo, Mn, Ce, Cs, 1 to 10 ppm Initially, YV04 powders predoped with neodymium or europium were obtained from Sylvania. Later, however, because of a desire to grow a series of crystals containing relatively broad concentration ranges of these dopants, it proved more convenient to start with pure YV04 and mechanically admix Nd2O3 or Eu@~ powders plus equimolar amounts of V2O5. The empty crucibles were preheated to 1900" to 1950oC, a temperature range where melting occurred readily. The powdered YVO4 feedstock was then added incrementally. However, a marked tendency toward

Jan 1, 1968

ONE HUNDRED AND FOURTEENTH MEETING OF THE INSTITUTE, MONDAY, FEBRUARY 19, TO THURSDAY, FEBRUARY 22, INCLUSIVE, 1917 Committee on Arrangements DAVID H. BROWNE, Chairman LAWRENCE ADDICKS Louts D. HUNTOON E. MALTBY SHIPP PERCY E. BARBOUR H.A. MEGRAW BRADLEY STOUGHTON GEORGE D. BARROW _ THOMAS T. READ EDWARD B. STURGIS KARL EILERS BURR A. ROBINSON ARTHUR L. WALKER F. T. RUBIDGE Summarized Program MONDAY, FEBRUARY 19 9:00 a.m. to 5.00 p.m. Registration at Institute Headquarters. , 10.00 a.m. Simultaneous Sessions on Geology and on Metallography.

Jan 2, 1917

By M. G. Corson

The iron-silicon alloy series has always been one of the most puzzling among the binary alloys. Examining the well-known mechanical properties of the iron-rich alloys only we meet the following situation: The ultimate strength and yield point of alloys worked and annealed under the usual conditions represent nearly a straight line function of the silicon content up to 1.5 per cent. silicon (Fig. I). Starting at the ultimate strength of 35,000 lb. and at a yield point of 16,000 lb. for pure electrolytic iron, one reaches a maximurn strength of 93,000 lb. and a maximum yield point of 74,000 lb. at 4.5 per cent. silicon. This corresponds to an increase in ultimate strength by 13,000 lb, per each per cent. of silicon added and nearly the same rate applies to the yield point. The data mentioned are taken from the investigation by T. D. Yensen,1 and while they do not exactly corroborate the results obtained by earlier investigators, they seem to be the most correct. Plastic properties of the alloys are controlled by a much more complicated relationship. Up to 2..5 per cent. Si, the elongation stays close to 50 per cent. (in 2 in.) and the area reduction amounts to 85 per cent., a situation that forms the usual feature of all alloys representing strictly solid solutions. The plasticity of the latter is always nearly equal to that of their base metal. Beyond 2.5 per cent. silicon, the situation becomes much more complicated. Yensen observed an enormous drop in elongation and area reduction at about 2.65 per cent. silicon, where the first hardly reaches 10 per cent. and the second is still lower; he found, however, a considerable recovery in plasticity at about 2.8 per cent. Si and up to 1.5 per cent. Si it is represented by 20 per cent. for the elongation and 30 per cent. for area reduction. Yensen&apos;s graphs, as shown in Fig. 1, indicate also a considerable drop in strength and yield point at the same point of 2.65 per cent. Si,