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By C. P. Karr

For several years, the Bureau of Standards has been working in cooperation with an Advisory Committee on non-ferrous metals on various phases of the production and testing of zinc bronzes. The work has dealt especially with the type of metal known as "Admiralty bronze" in England and as "Government bronze" in this country and consisting of 88 copper, 10 tin, and 2 zinc. Several reports have been made on this subject and these should be considered in connection with this paper.' First Series of Five Foundry Tests A very brief summary of the first series of five foundry tests has been made12 but for the sake of clearness the results are given here in different form. The five foundries cooperating in this investigation were: Ohio Brass Co., Mansfield, Ohio; Titanium Alloy Mfg. Co., Niagara Falls, N. Y.; Packard Motor Car Co., Detroit, Mich.; National Cash Register Co., Dayton, Ohio; Bureau of Standards, Washington, D. C. The object of the work was to determine whether uniform results could be obtained with this alloy in different foundries working under definite instructions. One of the participating foundries prepared, from virgin metal, a stock of ingots of the composition 88 copper, 10 tin, 2 zinc, and at the same time poured nine test bars from this melt of virgin metal. The results of the physical tests of these bars are shown in Table 1. Examination of this table shows that the highest and most nearly uniform results were obtained when the virgin metal was cast flat in chill molds and the lowest and- most variable results were encountered when it was cast, vertical in green-sand molds. In this, as in all other tables, the mean deviation was obtained by the usual method of taking the average of the differences of the individual values from the average values.

Jan 1, 1921

By F. J. Meringer, C. W. MacGregor

Various investigations have been carried out to determine the effects of cold-rolling on the common physical properties as represented by the yield strength, tensile strength, percentage of elongation and ordinary reduction of area. Very little information is available in the literature with reference to the effects of cold-rolling on the true stress-strain properties. Since the ordinary physical properties base both the stresses and the strains on the original dimensions of the test piece, which are greatly changed during the test, they are essentially empirical values and do not represent physically either true stresses or true strains. Consequently, they do not give an accurate picture of the effects of different conditions, both mechanical and metallurgical, on the strength and ductility of the material. It is not, however, the purpose of this paper to review the various advantages accruing from the use of true stress and true strain values, since these have been shown elsewhere,1-l2 but to utilize them in representing the various effects considered. The true stress S and true strain (e = q') values mentioned above for the tension test are defined by1 S =1/A and where P, A, Ao are the axial load, the instantaneous area and the original area of cross section, respectively. From simultaneous readings of the axial load and the dimension or dimensions determining the instantaneous area of cross section, the true stress-strain curve is constructed by using the relations given in Eq. I. It is then the object of this paper to discuss the general effects of cold-rolling on the true stress and strain values for a low-carbon steel together with the effects of age-hardening and directionality on these properties. Preliminary Investigations The material considered throughout the paper is a low-carbon steel of the following chemical analysis: C, 0.19 per cent; S, 0.118; P, 0.092; Mn, 0.85; Si, 0.01. The stock was received in bars, 7 by 3/4 in., and was first annealed for one hour at 1650°F. followed by a furnace cool. Photomicrographs of this material showed considerable directionality even in the annealed condition. In view of the possible effects of the nonhomogeneity and directionality in this material, it was considered important to investigate their influence on the true stress-strain diagrams. In addition, the effect of strain-aging in this steel was also made the subject of a preliminary study. Effect of Aging on True Stress-strain Properties Since a certain time element would elapse between the cold-rolling operation and the final tension tests, it was determined to investigate the aging character-

Jan 1, 1945

By R. F. Mehl, J. T. Ransom

For many years the Metals Research Laboratory of Carnegie Institute of Technology has been concerned with the statistical nature of the engineering properties of steel from an experimental viewpoint, particularly those properties representing ductility.' In the past three years new work has been directed toward evaluating the statistical nature of the endurance properties. It has been shown that both the fracture curve and the endurance limit in fatigue are markedly statistical in nature. The S-N curve (and the endurance limit) of ferrous materials is often determined with specimens which number as few as ten. The common procedure is to test the first specimen at a stress well above the expected endurance hmit. Each succeeding specimen is then tested at a progressively lower stress, until, after five or six tests, a specimen runs ten million or so cycles without failing. Two or three more specimens are then used to find the highest stress at which failure will not occur; the limiting stress determined in this way is called the endurance limit. It has now been found, however, that the variability in the fracture curve and in the endurance limit in heat-treated alloy forging steels is so great that S-N curves must be drawn on the basis of distribution curves which can be appraised only by statistical methods. Two methods have been adopted in this study: (1) straightforward statistical studies of cycles to fracture of a number of specimens at each of a series of stress levels, and (2) a new abbreviated statistical method, known as "staircase testing."2 The latter corisists in testing a series of specimens, one by one, with the test stress for any given specimen automatically

Jan 1, 1950

By H. W. Maynor, C. J. McHargue

DURING the course of an investigation of materials suitable for use as thermocouples at elevated temperatures by one of the authors, several nlolybdenum-rhenium alloys were prepared. Micrographs of an annealed alloy containing 25 pct Re (intended concentration; analysis not obtained) showed a number of twins, Fig. 1, suggesting a face-centered cubic structure. This note reports the structure and recrystallized wire texture of an alloy containing 25 wt pct Re. Alloys were prepared from 99.9 pct Mo (Fansteel Metallurgical Corp.) and rhenium obtained from the University of Tennessee (purity unreported). Powders were combined and briquetted at 56,000 psi and sintering was carried out at 2400°C for 5 hr in vacuum. Ingots so prepared were swaged at 982.2" to 1037.8oC into wires 0.036 in. diameter, a reduction in diameter of 85.6 pct. These wires were vacuum-annealed 1 hr at 2000°C. A North American Philips 114.59 mm powder camera and nickel-filtered copper radiation were used for structure determination. For the texture determination a Laue-type camera was used with zirconium-filtered molybdenum radiation and, because of the high background, aluminum foil was mounted next to the film. Exposures were taken with the wire perpendicular to the X-ray beam and tilted by 10". It was found that the X-ray pattern could be indexed on the basis of a face-centered cubic structure. Because of difficulties associated with obtaining a good X-ray pattern for this material, accurate parameter determinations were not made. An indicated parameter value of 3.70A was obtained. The X-ray data are given in Table I. The annealed wire texture was observed to be a sharp [111] texture. The spread about this fiber axis was k8" at the surface of the 0.036 in. wire. The annealed wire textures of aluminum have been reported as retention of the [Ill] deformation texture for anneals below 500°C and a new [1121 texture for anneals above 600°C.1 In copper wires, with a [Ill] plus [loo] deformation texture, results indicate a retention of this texture for annealing at lower temperatures and new components or the disappearance of components for annealing at higher temperatures.' The presence of the strong [I111 texture in the molybdenum-rhenium alloy after a 2000 °C anneal suggests that the deformation texture was the same. Acknowledgment The wires used in this study were prepared and heat-treated at the Institute for Atomic Research, and Ames Laboratory, Iowa State College, and the authors wish to express their thanks to the Institute for allowing the use of the material and permission to publish the results.

Jan 1, 1954

By J. Marin, H. A. B. Wiseman

This paper presents results of an experimental study dealing with the plastic stress-strain relations of aluminum alloy 14s-T6 subjected to combined biaxial tension and compression stresses. Plastic stress-strain relations for both constant and various types of variable stress ratios were determined and a comparison made with the simple flow theory of plasticity. THIS investigation was undertaken for two main purposes: 1—to obtain plastic stress-strain relations for Alcoa 14s-T6 when subjected to various combinations of biaxial stresses, and 2—to determine the validity of the flow theory in predicting plastic stress-strain relations for combined stresses. The biaxial stresses used were tension combined with compression. These stresses were produced by subjecting a thin-walled tube to axial tension and torsion. Various types of combined stress conditions were investigated. To provide control test data and information on the influence of biaxial stresses on the strength, the usual constant stress ratio type tests were made. These tests showed that the biaxial yield strength agrees approximately with the distortion energy theory. However, the Prager semi-empirical theory agrees best with the test results. For these constant stress ratio tests the plastic stress-strain relations were found to agree approximately with the flow theory. (For constant stress ratio the flow and deformation type theories are identical.) In view of the fact that the constant stress ratio tests cannot distinguish between the flow and deformation theories, a number of variable and special biaxial stress tests were made. These tests showed that the flow theory is inadequate, since large differences exist between the experimental and theoretical results. Special tests were also conducted to check the validity of the isotropic yielding assumption. This assumption is made in the linear-type flow theory. In these tests specimens were loaded in tension to predetermined values beyond the proportional limit stress. The tension load was removed from the specimen and the specimen was subsequently loaded in torsion to fracture. Other tests were applied with the order of torque and tension loading reversed. The nominal stress-strain curves for these two tests approximately coincide indicating that the assumption of isotropic yielding is valid. In addition, these tests verified the requirement by the slip theory of plasticity that prestraining below 140 pct of the proportioned limit stress in either torsion or tension did not influence the subsequent plastic stress-strain relations in tension or torsion. Another type of test was conducted to check the assumption that the axes of principal stress and strain coincide during plastic flow and variable stress conditions. These tests were conducted by applying combinations of axial tension, internal pressure, and torsional loads such that the axes of maximum principal stress could be rotated through 90" during the loading path. The results of those tests showed that the angle between the axes of principal stress and strain varied greatly and that the assumption of coincidence between axes of principal stress and strain is not valid. Introduction In various metal processes including forming of sheets, rolling of bars, and extrusion of rods, metals are subjected to stresses beyond the yield strength of the material. Often these stresses are not simple stresses acting in one direction, but are combined stresses acting in more than one direction. Structural and machine members are often subjected to combined stresses. To adequately determine the factors of safety for these members, it is necessary to know the plastic stress-strain relations of the material used for various combined stress conditions. Various theories have been proposed for predicting the plastic stress-strain relations for combined stress in terms of the simple tension plastic stress-strain relation for the material. To determine which theory might be adequate, test results must be obtained for various combined stress conditions, in order to compare the actual with the assumed theoretical behavior. Although there is considerable test data available for combined stress conditions in which the principal stress ratios are constant, relatively little test information is available for vari-

Jan 1, 1954

By Eugene Guccione

Evidence that the United States is gradually converting to the metric system of measurement can be perceived today even by housewives in a supermarket. The question is no longer whether but when the country will have completed the conversion. To the extent that any bickering about metrication still exists, the debate now centers on such issues as finding agreement on details of implementation, and whether federal legislation should speed up the metric-conversion process or allow it to proceed along its present evolutionary and voluntary course. Apparently, the voluntary or "make-haste-slowly" approach is gaining widespread support. According to The Research Institute of America, Inc., if and when federal legislation is enacted it will likely include the following national ground rules: (1) A National Metric Conversion Board will develop and submit to the President and Congress a comprehensive plan to achieve a coordinated, minimum-cost changeover. (2) The change- over will be completed 8 to 10 years after the board's plan goes into effect, and by that time the US will be predominantly, though not exclusively, metric. (3) Costs will "lie where they fall"; subsidies, special tax concessions, and antitrust exemptions will not be authorized by the legislation. (4) The changeover will be voluntary because of the recognition that while some firms can "go metric" in a matter of weeks, others may require 15 years or more, and a few might never convert. (5) In determining whether or not to convert, on an individual company basis, adherence will be to the "rule of reason-that is, ". . . do not convert unless the engineering, economic, or other benefits outweigh any metric-related disadvantages. No one is talking about rip- ping up our railroad tracks or rewiring our homes just to conform to the practice of metric nations in Europe." (6) Government is to be part of the solution, not part of the problem; in effect, says The Research Institute of America, the leverage of federal procurement will not be exerted to force-feed the metric changeover but will be coordinated with the sector-by-sector conversion of the economy.*

Jan 12, 1975

By C. P. Karr

FOR several years, the Bureau of Standards has been working in cooperation with an Advisory Committee on non-ferrous metals on various phases of the production and testing of zinc bronzes. The work has dealt, especially with the type of metal known as "Admiralty bronze" in England and as "Government bronze" in this country and consisting of 88 copper, 10 tin, and 2 zinc. Several reports have been made on this subject and these should be considered in connection with this paper.1 FIRST SERIES OF FIVE FOUNDRY TESTS A very brief summary of the first series of five foundry tests has been made,2 but for the sake of clearness the results are given here in different form. The five foundries cooperating in this investigation were: Ohio Brass Co., Mansfield, Ohio; Titanium Alloy Mfg. Co., Niagara Falls, N. Y.; Packard Motor Car Co., Syracuse, N. Y.; National Cash Register Co., Dayton, Ohio; Bureau of Standards, Washington, D. C. The object of the work was to determine whether uniform results could be obtained with this alloy in different foundries working under definite instructions. One of the participating foundries prepared, from virgin metal, a stock of ingots of the composition 88 copper, 10 tin, 2 zinc, and at the same time poured nine test bars from this melt of virgin metal. The results of the physical tests of these bars are shown in Table 1. Examination of this table shows that the highest and most nearly uniform results were obtained when the virgin metal was cast flat in chill molds and the lowest and most variable results were encountered when it was cast vertical in green-sand molds. In this, as in all other tables, the mean

Jan 9, 1919

By AIME AIME

THE meeting" of the Rare Minerals and Metals Committee was held Monday afternoon, Feb. 17; Donald M. Lidclell, chairman, presiding. The first paper (T. P. 279), "Progress in the Use of Tantalum," by George W. Sears, was read by Mr. Smyth. Dr. Sears' paper contains an interesting summary of the uses, alloys and ores of tantalum and a resume of present method of reduction. The uses of tantalum is based on its extreme rise to the reaction of even the strong mineral acids, its great avidity for the common gases and its capacity for transforming alternating to direct current. Tantalum, as an alloy material, has received considerable study and many alloys have been reported. Among them three types appear to .be most prominent, alloys of high melting point, hard alloys and acid rising alloys. As the estimated quantity of tantalum in the earth's crust is less than that of gold, it must be looked upon as n rare metal. Australia is the greatest producer and the Black Hills of South Dakota produce minor amounts. As the one type of mineral available contains both tantalum and columbium, the extracting and metallurgy of tantalum are difficult chemical processes. Greater simplicity in this and the development of a market for columbium would undoubtedly be of great benefit to the tantalum industry, andl make for a greater use of tantalum produced.

Jan 1, 1930

By R. V. Norris

The removal of mine-water by hoisting in tanks instead of pumping, while somewhat a reversion to the methods of the ancients, has come very rapidly into favor in the anthracite region of Pennsylvania during the past few years. In fact, so much so, that at the present time there are at least eight large collieries at which all the water is hoisted, and six more plants are in preparation. The particulars of the plants in operation and under construction, as far as decided on, are given in the tables on pages 107 and 108. Besides these, the Delaware, Lackawanna and Western R.R. Co. is constructing a hoist of large capacity for a depth approximating 500 feet, to be located in the Keyser Valley, near Scranton. The hoists will be driven by electric motors, geared directly to the sheaves. The Lehigh Valley Coal Company is planning a large hoist for the Packer collieries in the Shenandoah district, but no work has been done on this as yet. The earliest regular hoisting, I believe, mas done by means of semi-cylindrical tanks (Fig. 1) at the Nanticoke collieries of the Susquehanna Coal Company. These tanks were attached under the regular shaft-carriages, taking in water through six large clack-valves in the bottom, and discharging through an endgate opened by a lever which was operated by a guide-piece on the shaft head-frame. These tanks were designed July, 1880, by the late J. H. Bowden, one of the very early members of the Institute. Similar tanks are still used in emergencies at the Nos. 1, 2, 3 and 6 shafts of the company. The objections to. their use were: that water could only be hoisted during the night-shift, or when the shafts were not in use for hoisting coal, thus requiring a very large sump, and greatly limiting the water capacity of the plants; that the alternate wetting and drying

Jan 1, 1904

By W. T. Bishop, G. A. Crowe

While the literature in the United States on general polarographic technique is extensive, very little appears to be directly applicable to the analysis of flotation tailings. For this reason, it seemed worth while to present a few polarographic methods of ore analysis that have been in constant use in the laboratories of the Hercules Experiment Station for the past few years. At the time of our initial investigation of the polarographic method, there was little or no mention of its specific application to flotation tailings. It was therefore necessary for us to establish suitable conditions for the analysis of our flotation tailings and to consider possible interfering constituents. The polarograph, or dropping mercury electrode, method was discovered in 1925 by J. Heyrovsky and M. Shikata,1 of the Charles University, Prague. This method has since received extensive development and the literature contains many articles on the use of the polarograph for the quantitative determination of metals as well as anions, oxygen in solution, and reducible organic compounds. Kolthoff and Lingane,² by the publication of their book, "Polarography," in 1941 did much to advance the knowledge and use of the polarograph. In chapter 25 of that book, methods for the polarographic analysis of brass, steel and iron products, alloys, and zinc ore are given. Aluminum,³ cadmium,³,4 cobalt,4 cop-per,³-9 gold,10 iron,3,11 lead,³,l2,l³ molybdenum,14 nickel,4,8,9 tin," and zinc³,4,5,7 in ores have been analyzed by the polarograph. However, most of the work on tailing samples has been published in Russian journals and translations are not yet readily available. In this paper we will describe the method that was developed and used in our laboratory for the determination of copper, zinc, and lead in flotation tailings. Principle OF the Method The polarograph is an instrument for applying a potential to a mercury pool and a dropping mercury electrode separated by a solution, and for measuring the resultant electrical current. The procedure is essentially a small-scale electrolysis, in which the voltage required to reduce or oxidize the material identifies it qualitatively and the current measures the concentration quantitatively. Different constituents in a sample may often be determined simultaneously provided they reduce at sufficiently different voltages. An example is the determination of copper and zinc in the same solution. The reduction potentials are quite far apart, as shown in Fig. I. The polarographic method is particularly useful in the range of concentration between those normally determined by spectographic and chemical methods. In

Jan 1, 1947

By G. A. Crowe, W. T. Bishop

While the literature in the United States on general polarographic technique is extensive, very little appears to be directly applicable to the analysis of flotation tailings. For this reason, it seemed worth while to present a few polarographic methods of ore analysis that have been in constant use in the laboratories of the Hercules Experiment Station for the past few years. At the time of our initial investigation of the polarographic method, there was little or no mention of its specific application to flotation tailings. It was therefore necessary for us to establish suitable conditions for the analysis of our flotation tailings and to consider possible interfering constituents. The polarograph, or dropping mercury electrode, method was discovered in 1925 by J. Heyrovsky and M. Shikata,1 of the Charles University, Prague. This method has since received extensive development and the literature contains many articles on the use of the polarograph for the quantitative determination of metals as well as anions, oxygen in solution, and reducible organic compounds. Kolthoff and Lingane,² by the publication of their book, "Polarography," in 1941 did much to advance the knowledge and use of the polarograph. In chapter 25 of that book, methods for the polarographic analysis of brass, steel and iron products, alloys, and zinc ore are given. Aluminum,³ cadmium,³,4 cobalt,4 cop-per,³-9 gold,10 iron,3,11 lead,³,l2,l³ molybdenum,14 nickel,4,8,9 tin," and zinc³,4,5,7 in ores have been analyzed by the polarograph. However, most of the work on tailing samples has been published in Russian journals and translations are not yet readily available. In this paper we will describe the method that was developed and used in our laboratory for the determination of copper, zinc, and lead in flotation tailings. Principle OF the Method The polarograph is an instrument for applying a potential to a mercury pool and a dropping mercury electrode separated by a solution, and for measuring the resultant electrical current. The procedure is essentially a small-scale electrolysis, in which the voltage required to reduce or oxidize the material identifies it qualitatively and the current measures the concentration quantitatively. Different constituents in a sample may often be determined simultaneously provided they reduce at sufficiently different voltages. An example is the determination of copper and zinc in the same solution. The reduction potentials are quite far apart, as shown in Fig. I. The polarographic method is particularly useful in the range of concentration between those normally determined by spectographic and chemical methods. In

Jan 1, 1947

By J. O. Whiteley, C. Dietz

It is difficult to give a refining outline that may be followed for any and all combinations of the platinum metals; different combinations require different methods of attack. This paper does not pretend to go into all of the reactions of the metals of the platinum group, but will outline the commercial refining of platinum scrap. Typical Platinum Scrap As a concrete case, let us take 100 oz. of miscellaneous scrap, made up of jewelry scrap, dental scrap and laboratory ware. This lot will contain some platinum, palladium, iridium, ruthenium, rhodium, gold, silver and copper. The first problem is to get all of the metals in solution. If the scrap is principally platinum, palladium and gold, a treatment with aqua regia is the course to pursue; but if the scrap contains alloys high in iridium or ruthenium, aqua regia will act too slowly. In the case in hand, we are going to presume that we have scrap high in iridium and ruthenium, and proceed accordingly. Obtaining Residue A Place the scrap, together with six times its weight of granulated test lead, in a solid carbon crucible. This crucible may be placed inside a clay graphite crucible packed with charcoal, to prevent the excessive oxidation of the carbon crucible by the furnace blast. Place a tight cover on the carbon crucible; heat gradually to a good red heat and allow it to soak in the heat for 4 or 5 hr. After the leaded mass is cool, dissolve in dilute nitric acid (1-6) on a steam plate or sand bath. This dissolves practically all of the lead and most of the palladium, silver and copper, together with seme of the platinum and rhodium, and leaves the iridium, ruthenium, gold, and most of the rhodium and platinum as a finely divided residue. Siphon off the clear solution and treat the residue with another portion of dilute nitric acid to insure the solution of the lead and copper. The second nitric acid solution is added to the first, and the residue is filtered on suction and washed thoroughly with hot

Jan 1, 1928

By S. Jana, C. M. Wayman

The reverse transformation of bcc martensite to the fcc phase was studied in an Fe-33.95 wl pct Ni alloy by nzeans oj dilatometry, melallography, and electron microscopy. Upon "slozc" heating (-1°C per min) length cJmnge us temperature plots showed u gradual contracLion over the temperature range 200" to 280"C ,followed by a more abrupt contraction beginning a1 -280°C. Howet,ev, zchen the heating rate was increased -4°C per tnin, no gradual contraction was observed and only the abrupt contraction starting at -2BO"C was found. Thus on slower heating- the AS "temperature" for the subject alloy, unlike the MS temperature, is better defined as a range of temperatures. Both optical and transmissiorl electron microscope observations showed that some of the martensite plates exizibited a partial loss of transformation twins during reversal. The midvib region of the martensite plates disappeaved relatively early duirng the reversal. Metallographic observations slowed that the earliest detectable stage of the rezlerse tvansforrvration begins (axd Moues inulardly) at The Martensens i te - parent interface. At higher temperatirres, the. formation of martensitically reversed jcc plates within the bcc martensite plales was observed. It is concluded that the reverse transformation consists of a diffusion less process (martensitic); but this is ps-obably aided by a prior or simultaneous dijjusiorz-comltvolled process, at leasl in the case of slower heat-ing' experiments. ALTHOUGH numerous investigations have dealt with the parent-to-martensite ("forward") transformation (fcc — bcc) in Fe-Ni alloys, comparatively little is reported on the ("reverse7') martensite-to-parent transformation.'-4 Even though such reverse transformations have been studied in detail in some nonferrous systems, one of the difficulties of studying the reverse transformation in most ferrous mar-tensites is that the martensite decomposes by tempering during heating. However, carbonless Fe-Ni alloys do not exhibit this difficulty since the transformation in these alloys is completely reversible. The present investigation represents an attempt to shed more light on the nature and mechanism of the martensite-to-parent transformation. 1) EXPERIMENTAL PROCEDURE 1.1) Alloy Prepatation. Fe-Ni alloys of compositions near 34 wt pct Ni were prepared from zone-refined iron (99.994 wt pct Fe) and high-purity nickel (99.999 wt pct Ni) by induction melting in recrystallized alumina crucibles in an argon atmosphere, with prior vacuum evacuation to 10"3 mm Hg. The alloys were homogenized by induction stirring in the molten state for 5 min. After solidification, the alloys were further homogenized in evacuated quartz capsules for 96 hr at 1230°C. 1.2) Dilatometry. Slices of the ingot were hot-forged (750°C in air) into approximate rod form and these specimens were then hot-swaged (750°C in air) into long cylindrical rods 0.55 mm diam. From the rods, specimens about 1 in. long were cut. These were then vacuum-annealed for 24 hr at 1200°C, cooled to room temperature, and subsequently transformed to martensite in liquid nitrogen (whereby about 40 pct transformation was obtained). Dilatation measurements were made by observing length changes in a vacuum dilatometer with an externally mounted LVDT sensing element. 1. 3) Preparation of Electron Microscope Specimens. Slices of the ingots were cold-rolled (with intermediate vacuum anneals) to -0.020 in. Out of these rolled sheets, specimens (about 1 by 1 in.) were cut. These were then vacuum-annealed, transformed to martensite by cooling in liquid nitrogen, and subsequently heated from room temperature to various temperatures to effect either partial or complete reverse transformation. These specimens were then chemically polished to 0.002 in. in l:l HsOz (30 pct) and &PO4 (85 pct) solution, and thinned to electron transparency in an electrolyte consisting of 150 g CraOs, 750 ml glacial acetic acid, and 30 ml ~~0.~ Observations were made with a 100-kv Hitachi HU-11 electron microscope equipped with an HK-2A tilting device. 1.4) Optical Microscopy. Metallographic observations were made with a Leitz MM5 metallograph on the same 0.020-in. sheet specimens as were used for electron microscopy and on bulk specimens which were 0.2 in. or more on a side. The chemical thinning solution when cooled below 20°C also served as an etchant for this alloy. Observations of surface relief were made with a Zeiss interference microscope employing a Thallium light source of wavelength 0.54 p. Specimens for interference studies were prepared by two-stage polishing on Buehler vibromet polishers using 0.3 and 0.05 p alumina abrasives. 2) EXPERIMENTAL RESULTS 2.1) Comparison of the MS,AS, and Af Tempera-tures wTth Previous Re sults. The AS aLd Af tempera -tures of several Fe-Ni alloys were determined dila-tometrically. The MS temperatures of the same alloys were determined by continuously lowering the temperature using a mixture of isopentane and liquid nitrogen and observing the highest temperature at which a prepolished specimen showed surface upheavals. For the present the As temperature is defined as the temperature at which an abrupt decrease in length occurs in the dilatation plot. The Ms,As7 and A determinations in the present investigation and those of Kaufman

Jan 1, 1968

By John M. Hartman

On May 19th, 1857, an English patent was granted to E. A. Cowper for heating air or other gases under pressure by means of a regenerator inclosed in an air-tight iron case, having between the regenerator and case a lining of brick. This patent provided for heating the stoves by a separate fireplace, or by gas direct from the blast furnace. A number of forms of interior arrangement of the brickwork are shown in the drawings; also hollow poppet valves with hollow stems, and a pipe inside of the stem for circulating the water; the valve seats have coil cast in them for water circulation to keep them cool; slide valves, with snake coil cast in the discs, are shown, and the use of cold air for cooling the valves is also described. The combustion-chamber of these stoves was central, and openings mere provided at the top and bottom to get into the stoves. These Cowper stoves are all circular in section. November loth, 1865, an English patent was granted to Thomas Whitwell for regenerative stoves for heating air or gas, provided with cleaning openings at the top and bottom capable of being closed with firebrick plugs and doors. The drawings show a rectangular stove inclosed in an iron case. The interior brickwork has numerous upand-down passages through the stove, but there is no claim on the interior construction. March 3d, 1868, an English patent was granted to Charles Cochrane for a slide valve to be subjected to high heats. The disc of this valve was hollow, and had a circulation of water through it by the two hollow stems that operated it. The valve-seat was detachable and had a coil cast in it, through which water circulated. The valve and seat were placed on an incline to the body to cause the valve-disc to lie on the valve-seat. A cap was placed on the bottom of the body to get at the interior readily. January 5th, 1870, an English patent was granted to Siemens, Cowper and Cochrane for the construction of regenerators in firebrick stoves, with numerous vertical passages of sufficient size to allow a brush to pass through and clean them. These passages had slight projections on the sides to tarn the air over and over as it passed through. A claim also covered the use of horizontal passages connected at each end alternately, and the use of blasts or jets of air,

Jan 1, 1880

By Joan M. Hartman

ON May 19th, 1857, an English patent was granted to E. A. Cowper for heating air or other gases under pressure by means of a regenerator inclosed in an air-tight iron case, having between the regenerator and case a lining of brick. This patent provided for heating the stoves by a separate fireplace, or by gas direct from the blast furnace. A number of forms of interior arrangement of the brickwork are shown in the drawings; also hollow poppet valves with hollow stems, and a pipe inside of the stem for circulating the water; the valve seats have coil cast in them for water circulation to keep them cool; slide valves, with snake coil cast in the discs, are shown, and the use of cold air for cooling the valves is also described. The combustion-chamber of these stoves was central, and openings were provided at the top and bottom to get into the stoves. These Cowper stoves are all circular in section. November 10th, 1865, an English patent was granted to Thomas Whitwell for regenerative stoves for heating air or gas, provided with cleaning openings at the top and bottom capable of being closed with firebrick plugs and doors. The drawings show a rectangular stove inclosed in an iron case. The interior brickwork has numerous up-and-down passages through the stove, but there is no claim on the interior construction. March 3d, 1868, an English patent was granted to Charles Cochrane for a slide valve to be subjected to high heats. The disc of this valve was hollow, and had a circulation of water through it by the two hollow steins that operated it. The valve-seat was detachable and had a coil cast in it, through which water circulated. The valve and seat were placed on an incline to the body to cause the valve-disc to lie on the valve-seat. A cap was placed on the bottom of the body to get at the interior readily. January 5th, 1870, an English patent was granted to Siemens, Cowper and Cochrane for the construction of regenerators in fire-brick stoves, with numerous vertical passages of sufficient size to allow a brush to pass through and clean them. These passages had slight projections on the sides to turn the air over and over as it passed through. A claim also covered the use of horizontal passages connected at each end alternately, and the use of blasts or jets of air,

Jan 1, 1880

By B. H. Kear

Clustering of slip bands in different systems has been observed in both ordered and disordered Cu3Au crystals compressed in the <110> orientation. Certain features of the slip band patterns are explained in terms of reactions between dislocations with Burgers vectors at 120 deg; in a few rare cases, the slip band evidence suggests that the Products of such reactions form diffuse tilt boundaries between the differently slipped regions of the crystal, similar to the known behavior of ionic crystals, but not nearly so well defined. WHEN crystals with orientations favorable for multiple slip undergo plastic deformation, slip may occur in different systems in localized regions, so that clusters of slip bands are developed. This phenomenon has been observed in fee1-4 metals and also in ionic crystals having the sodium chloride structure.5-8 In the ionic crystals, the boundaries formed between the differently slipped regions of the crystal assume characteristic orientations and are associated with macroscopic tilts that are plainly visible on the sides of the crystal. Recently, this interesting feature was explained in terms of the formation of diffuse low-angle boundaries as a result of interactions between families of glide dislocations in the different systems meeting in the boundaries.9 This paper describes an attempt to obtain similar evidence for boundary formation in an fee crystal. The alloy Cu3Au was chosen for the present study simply because this material is currently being used in a general study of differences in deformation behavior of the ordered and disordered phases of this alloy, which will be described elsewhere. EXPERIMENTAL PROCEDURE The two specially oriented compression specimens used in the present study were prepared from a melt-grown single crystal by careful cutting, grinding and polishing. The finished specimens were about 6 mm by 2 mm in cross section by 6 mm tall, with their ends parallel to (101) and sides parallel to (111) and (121); the broad faces of the specimens were made parallel to (711). Both specimens were annealed in an evacuated quartz tube at 850oC for several hours, slowly cooled to 500°c, and then quenched into water in order to obtain the disordered state for the alloy. One of the specimens was partially ordered (with S- 0.8) by reannealing at 350oC for 100 hr. After these annealing treatments, both of the specimens were electropolished. 10 Finally, the specimens were compressed in the [loll orientation and their stress-strain curves were recorded. The deformation was carried out in increments of a few percent strain. At each stage in the deformation the specimens were unloaded, removed from the compression jig, and examined optically for slip bands. Before reloading, the specimens were repolished, so that the observed slip band patterns were characteristic of a particular stage in the deformation. EXPERIMENTAL RESULTS Fig. 1 show!; the stress-strain curves for the ordered and disordered specimens and also indicates the stages 1, 2, and 3 where the deformation was interrupted for examination of slip bands. The curves show marked differences in flow stress and in work hardening rate in the two specimens, as observed by previous workers.11,12 Also, it was found, in agreemement with the observations of Taoka and Sakata,&apos;3 that the plastically deformed disordered alloy showed the characteristic coarse slip bands of alloys, whereas the ordered alloy exhibited a fine slip band structure similar to that of pure metals. Slip Band Observations. In what follows, the description of the slip band patterns, with accom-

Jan 1, 1962

By AIME AIME

NATURE was in a smiling mood on December 18, 1883. On that day, Chester Alan Fulton, the sixty-first President of the American Institute of Mining and Metallurgical Engineers, was born, and she endowed him with every good quality within her reach - looks, physique, intelligence, and character. Brought up in the valley of the Hudson River, with the mighty Palisades which make it the "Rhine of America," he has lived up to his early promise - as a man, as an engineer and as a friend.

Jan 1, 1943

By A. W. Schlechten, A. H. Larson

Equilibrium H2S/H2 ratios were determined as functions of temperature (500o to 900°C) and composition in a hydrogen-circulation apparatus. Within the composition range studied there exists a two-phase region of "Zr3S4" and "ZrS2". The upper composition limit of this two-phase region is hounded by a disulfide phase and is practically constant over the temperature range investigated. The lower composition limit of this two-phase region is bounded a "Zr3S4 " phase and varies appreciably with tem- perature. The upper composition limit of the homogeneous region of the disulfide phase is not definitely determined, but it appears to he bounded by the stoichiometric composition of ZrS2. The lower composition limit of the homogeneous region of the Zr3S4 phase could not he determined due to the extremely low values of the equilibrium H2S/H2 ratios. Various thermodynamic quantities are evaluated from the data. PUBLISHED free-energy data for the Zr-S system are practically nonexistent. Strotzer, Biltz, and Meisel1 measured the sulfur pressures for the reaction 2ZrS2(s) + S2(g) = ZrS3(s) in the temperature range 783" to 874°C. The average heat of reaction calculated from the temperature dependence of the sulfur pressure is -47 keal. It should be noted, however, that according to these investigators, the two-phase region as determined by sulfur pressure constancy under isothermal conditions extended from approximately ZrS2, 3 to ZrS2.7. From consideration of X-ray data they concluded that the homogeneous regions of the disulfide and trisulfide phases are ZrS1.8-2.0 and ZrS2.8-3.2, respectively. Hahn and coworkers2 have made a structure study of the zirconium sulfide phases. They summarized the zirconium sulfide phases as follows: the compounds ZrS3 and ZrS2 with narrow homogeneous regions, a "Zr3S4" phase with a homogeneous region roughly within the limits of ZrSl.5 and ZrSo.9, the compounds ZrS and Zr4S3, and a "Zr3S2" phase with a homogeneous region within the limits ZrSo.8 and ZrSo.5. It is noted that the compounds ZrS and Zr4S3 are only formed in the gaseous state through sublimation of a phase which has the approximate composition of the compound. This paper describes the determination of the stability of the zirconium sulfide phases by a hydrogen-reduction method in which hydrogen is circulated over the heated sulfide until equilibrium is attained. The resulting H2S-H2 mixture is then analyzed. Partial molar free energies, enthalpies,

Jan 1, 1964

By Jacques B. Wertz

Among the parameters to be considered in the continuous search for new base-metal deposits, there often is a stratigraphic controlling factor that seems instrumental in the localization of ore. In British Columbia, for instance, the Upper Triassic as well as Lower Jurassic volcanics mixed with sediments are a useful indication in the search for copper while, in some parts of Australia, rhyolite bodies seem to be the favorable indicator, and this always within the geosynclinal environment. In Arizona, this stratigraphic factor becomes highly significant and it will be shown here that a large number of ore deposits are to be located around the flanks of ancient calcareous basins or depressions, preferentially corresponding to a certain optimum thickness as revealed by isopachs. The Martin limestone, of Devonian age, is already known for its basal O&apos;Carroll bed which coincides with mineralization at places, and this is a relatively minor control. However, several limestone basins outlined by isopachs are in reality of greater importance as they localize mining districts. Indeed, most mines are found to coincide with a specific thickness of limestone while occurring simultaneously close to major, regional fracture intersections. The regional fractures in question were interpolated and extrapolated from known, important fault expressions, integrating quite well with the existing geology and further confirmed by minor criteria such as contacts, igneous plugs, axes of elongation of batholiths, dikes, etc. Although elements of subjectivity remain, this grid of fractures can be used quite successfully as a working hypothesis in the search for ore. Results of the present study which superposes major structural

Jan 1, 1971

Secretary Membership Committee Increase of Membership Papers and Publications Committee Library Committee Treasurer Report of the Secretary TO THE BOARDOF DIRECTORASN D THE MEMBEROS F THE AMERICANIN STITUTE OF MINING AND METALLURGICAENL GINEERS GENTLEME:N As will be shown by the special reports of the Finance, Membership, Library, Papers and Publications, Increase of Membership, and other standing Committees, together with that of the Treasurer, the year 1927 was one in which the Institute made very satisfactory progress in a number of directions. In total numbers the membership is no larger but in revenue from dues there has been a marked increase. This has been due to the promotion to full membership of Junior Associates of earlier years, to the larger proportion that come in originally as members rather than juniors, and to the keener interest in the work of the Institute reflected in prompter payment of dues. The latter is important, since experience shows that of those who fall behind a large number must ultimately be dropped for non-payment. Conditions in the mining industries have been healthy though not booming. It has been much easier for members to find employment and meet their financial obligations but there has not been that flow of young men into mining, and hence in part into the Institute, that characterized certain earlier years. Rather the tendency toward centralization and larger industrial units has restricted the number, though not the scope, of opportunities for technical men in the mineral industries. The Institute is constantly receiving resignations from members crowded out of mining into other lines of activity. On the other hand, those who remain in mining and metallurgy have a greatly increased necessity for i,dormation and contacts with technology. A few years ago many superintendents and most foremen were non-technical men. Today the reverse rule obtains and shift bosses and men who occupy even lower positions in industrial units are called upon to know and to apply such an amount of technical knowledge that graduate engineers are the rule rather than the exception. The curious situation has obtained that with a much smaller enrolment of students in the schools of mining and metallurgy there has been at times an actual shortage of young engineers for beginners&apos; jobs. The young men retort that the conditions of employment and pay offered in mining are not equal to those in other lines and, while it is undoubtedly true that the young engineer beginning in mining is able to start under conditions markedly better as to pay, living, and responsibility than did the men who are now leaders, they are required to know much more and have usually spent more in time and money to qualify for their jobs. The whole matter is one which warrants much more attention than has been given to it. For the Institute it is important since the young men

Jan 1, 1928