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By F. F. Aplan

Pollution control will be of utmost importance in the 1970's. In this area, the mineral process engineer has a special competence to understand and remedy many pollution situations. There is an old adage that goes, "Build a better mouse- trap and the world will beat a path to your door." Would that it were so, but the reality of the situation is such that, just as a supplier must sell his machine, a professional man must sell his competence. It is a sad but true fact that mineral processing engineers have not done a very good job in selling their extensive competence in the control of a broad range of pollution problems. Recently one of our students visited a paper pulp mill where he was shown a foam fractionator used to remove paper pulp fibers from plant discharge waters. "Foam fractionator hell, that's a flotation cell!'' was his comment. Ah so, it would appear that large numbers of technical people consider themselves experts on "foam fractionation" Or is it that we have been very remiss in demonstrating the usefulness of our equipment and processes and our professional competence to solve, these pollution problems?

Jan 1, 1970

By William E. Ford, Edward Salisbury Dana

The Silicates are m part strictly anhydrous, in part hydrous, as the zeolites and the amorphous clays, etc. Furthermore, a large number of the silicates yield more or less water upon ignition, and in many cases it is known that they are, therefore, to be regarded as basic (or acid) silicates. The line, however, between the strictly anhydrous and hydrous silicates cannot be sharply drawn, since with many species which yield water upon ignition the part played by the elements forming the water is as yet uncertain. Furthermore, in the cases of several groups, the strict arrangement must be deviated from, since the relation of the species is best exhibited by introducing the related hydrous species immediately after the others. This chapter closes with a section including the Titanates, Silico-titanates, Titano-niobates, etc., which connect the Silicates with the Niobates and Tantalates. Some Titanates have already been included among the Oxides.

Jan 1, 1922

By Helmut Thielsch

IN recent years an ever increasing amount of interest has been directed toward research studying the principles and various applications of sonic and supersonic waves. Though still in their early stages of practical development, sonic vibrations are already used in the emulsification and degasification of liquids. Metals exposed to sonic or ultrasonic vibrations while solidifying show a considerable amount of grain refinement. Often sound waves are applied instead of radiography to test engineering materials for internal cracks and flaws.1 In the field of pure research these waves are used in dispersion and also in coagulation of particles or liquids in gaseous or, under certain conditions, in other liquid systems. In the settling and thickening of slurries considerable time is necessary to compress the solid particles and to squeeze out the liquid to obtain as low a dilution (liquid to solid ratio) as possible. Various methods have been developed to increase the amount of coagulation of the very fine solids (colloidal or semicolloidal) and to shorten the over-all time. The addition of small amounts of electrolytes and the warming of the suspension represent merely the more important techniques. Some of the effects of supersonic vibrations have been reported previously.2,6 From preliminary studies, therefore, it was hoped that by application of sonic vibrations it would be possible to reduce the time required to thicken such materials to a specific dilution, as well as to thicken to lower ultimate dilutions than could be obtained by quiescent settling alone. By increasing the volume thickened per unit time-i.e., improving the plant efficiency-great savings in equipment and time would be obtained for industrial processes. Also, faster settling rates should result if coagulation of particles could be increased. Experiments have been conducted for a period of several months in the Allis-Chalmers laboratory to study the effect of sonic vibrations on settling of particles of different sizes and concentrations. APPARATUS The sedimentation apparatus used in these experiments is illustrated in Figs. I and 2. The essential features are the stationary field coil and the movable voice coil. Both windings are placed around a solid iron core. A leather diaphragm connected to the steel frame holds the voice coil in place. A brass rod is fastened to the voice coil with a metal disk connected to the other end. This disk is sealed to the lucite cylinder with a flexible rubber diaphragm. The lucite tube is 17 in. long; its inner diameter is 2 ½in. and the wall thickness is ¼ in. The tube is calibrated on the outside in 10 c.c. divisions for a total of 1000 cubic centimeters.

Jan 1, 1946

By C. S. Yust, Lida K. Barrett

The change in shape of the void in a sirzterir~g copper mass has been investigated as a juntction of' density. A serial sectioning' technique was used to eoaltrate the irregular shape of the void at two levels qf density. A measure of the void size and configuration, the proximity number, is defined and used to describe the progress of void removal. The process of. void removal deduced front the observations of this study contrasts with current sintering models in that it takes into account the irregularity of structure of a sintering mass and demonstrates that isolated Porosity does not occur first as spherical pores, but as large, definitely nonspherical sections of the void void volume. The process of sintering, about which there is much practical and theoretical knowledge, has evaded a direct and thorough analysis despite the intensity with which it has been studied for 60 years or so. This is due, of course, to the complex structure of a sintering mass and the inability to observe directly the development of a fully dense solid from the initial particulate arrangement. Extensive theoretical analyses have been based on the adoption of one or another of several model systems, that is, by visualization and analysis of some sort of regular assembly or arrangement of geometric "particles" approximating the conditions of a sintering mass. It seems appropriate at this time to try to examine experimentally in some detail the extent to which a sintering mass of irregular particles dlffers from these models. Many models deal with neck growth and the initial stage of sintering and follow the direction established by ~ucz~nski' in 1949 for the sintering of spheres to flat plates. Recently Johnson and cutler2 have adapted these models to sintering of powder masses. coble3 has presented a mathematical model for sintering that applies to the middle and final stages of the process. These papers, without exception, assume a regular geometry, generally spheres in contact in a regular array. Rhines~ and coworkers, however, are studying the sintering process by applying a model based on the topological concept of genus which permits them to consider an irregular structure. whites has described the various models with the exception of that of Rhines et al., and the assumptions on which they are based and their shortcomings. The present paper examines the geometric changes that occur in the powder mass during sintering by examination of the void. The method is to analyze a series of partially sintered structures and to propose from this analysis the sequence of events which occur in the removal of the void space as a sintering mass progresses from a collection of individual particles to a solid body. The irregular nature of the stacking of particles and of the particles themselves will be taken into account. The significant points derived from this study are: first, accurate reconstructions of the irregular void shapes are presented; second, it is clearly established that closed porosity occurs first as widespread volumes of interconnected porosity, definitely nonspherical in shape; and third, a new factor, the proximity number, is defined, which serves in this paper as a tool for describing the void shape changes observed, and which will be used in a later paper as part of the basis of a mathematical model for sintering. While the specific material studied is copper, the observations are thought to be relatively general as indicated by comparison of the results with partially sintered structures in other materials presented in the literature, both metallic and nonmetallic. EXPERIMENTAL PROCEDURE Four series of specimens representing progressive stages of the sintering process were prepared by sintering high-purity copper powder for various time periods. A relatively large particle size was used so that the void-solid interface could be readily distinguished at low magnification. In three series of specimens a loose stacking of particles was obtained by pouring powder into an alumina mold and lightly tapping the mold. The green density of such compacts was approximately 40 pct of theoretical density. Two of these three series utilized irregularly shaped particles in the size range -230 +325 mesh, one series sintered in vacuum and one in hydrogen at 950°C. The third series of loosely stacked particles consisted of spherical particles in the size range -270 +325 mesh, sintered in hydrogen at 950°C. A fourth series was prepared from compacted irregular particles sintered in hydrogen at 950°C. The specimens for this series were formed by lightly pressing the irregularly shaped particles in a steel die; the green density of the pressed pellets was approximately 60 pct. The irregularly shaped particles used in this study are shown in Fig. 1. The density of these particles, measured by a toluene picnometer technique, is 98.2 pct of theoretical density. Each particle is highly convoluted, and in some instances appears in cross section to contain internal porosity. The density measurement, however, indicates that completely enclosed porosity is very small so that the individual particles have a highly irregular surface but are essentially fully dense copper. Therefore, most of the void space that appears in two dimensions to be isolated within the particle is actually at the particle surface and connected to the external void in the dimension not included in the plane of the cross section. The void space that appears as void surrounded by the par -ticle or within folds in the particle w~ll be r~fc\r?

Jan 1, 1968

By E. H. Dix

The work of Merical and other investigators indicates that the phenomenon of age-hardening in alloys of the duralumin type is primarily dependent upon the variation in the solubility of copper with temperature. In addition to copper, however, these alloys contain small amounts of magnesium, silicon, manganese and iron, which may affect the age-hardening either directly or indirectly. The effect of these elements on the solubility of copper and on the manner in which this solubility varies with the temperature is of considerable interest, therefore. The effect of magnesium is of especial interest because apparently it exerts a marked effect on the natural or room-temperature aging of alloys of the type described.2 A series of investigations3 has been in progress in the research laboratories of the Aluminum Company of America to determine the functions * Metallurgist, Aluminum Research Laboratories. f Metallurgical Division, Aluminum Research Laboratories. Formerly with Metallurgical Division, Aluminum Research Laboratories. 1 P. D. Merica, It. G. Waltenberg and H. Scott: Heat Treatment of Duralumin. U. S. Bur. Stds. Sn. Paper 347 (1910). 2 M. Gayler: Constitution and Age-Hardening of Alloys of Aluminum with Copper, Magnesium, and Silicon in the Solid State. Jnl. Inst. Met. (1922) 28, 213. W. Fraenkel: Vergutbare Aluminiumlegiengen. Ztsch. Melallkunde. (1920) 12, 427. E. H. Dix, Jr.: Note on the Microstructure of Aluminum-Iron Alloys of High Purity. Proc. Amer. Soc. Test. Mat. (1925) 26, Pt. 2, 120. E. H. Dix, Jr. and H. H. Richardson: Equilibrium Relations in Aluminum-copper Alloys of High Purity. Trans. A. I. M. E. (1926) 73, 560. E. H. Dix, Jr. and W. D. Keith: Equilibrium Relations in Aluminum-manganese Alloys of High Purity. Proc. Inst. Met. Div., A. I. M. E. (1927) 315. E. H. Dix, Jr. and A. C. Heath, Jr.: Equilibrium Relations in Aluminum-silicon and Aluminum-iron-silicon Alloys of High Purity. Proc. Inst. Met. Div., A. I. M. E. (1928) 164. E. H. Dix, Jr. and F. Keller: Equilibrium Itelations in Aluminum-magnesium Alloys of High Purity. Proc. Inst. Met. Div., A. I. M. E. (1920) 351. E. H. Dix, Jr., F. Keller and R. W. Graham: Equilibrium Relations of Aluminum-magnesium Silicide Alloys of High Purity. Trans. A. I. M. E., Inst. Met. Div. (1931) 404. W. L. Fink and K. R. Van Horn: Constituents of Aluminum-iron-silicon Alloys. Trans. A. I. M. E., Inst. Met. Div. (1931) 383.

Jan 1, 1932

By Paul M. Tyler

MARKETWISE the year 1935 was rather a good one for most of the rare and minor metals; as a class they climbed out of the depression much faster than the common metals. The diamond market, too, was better than it had been for years, attributable only in part to investment buying, as there was a genuine pick-up in consumer demand. Wars and rumors of war tended to speed up purchases of certain metals, but consumption for peaceful purposes was the principal factor. Significant was the important role played by new industrial uses. New discoveries during the year were disappointingly few, considering the broad extent of this research frontier. Scientific developments were far from being at a stand-still, of course, but the dominant note was the cashing in on research consummated in former years. With even a moderate upturn in general business a surprising number of laboratory ideas donned overalls and found jobs in industry.

Jan 1, 1936

By W. G. Bearden, G. C. Howard, J. W. Spurlock

An investigation of the factors af-fec.ting the inter-zonal flow of fluids in the casing-wellbore annrc1rt.s of an oil or gas ivell is presented Laborntory tests revealed that failure of the caring-cement bond allows communi-cation of fluid at pressure differentials near 1.000 psi. Perforating with a 11011011: carrier gun does not shatter or crack the cement sufficiently to allow communication through these cracks and does not seriously affect the casing-cement bond failure pressure. The pressure to cause communication at the casing-cement bond can he increared to 3,000 psi by. limiting pipe deformation during cementing and subsequent operations. Communication can be prevented, however. up to pressures sufficient to cause the cement to fail or the casing to col-lapse, by attaching to the casing a seal ring of deformable ruhber molded between two steel flanges. When installed, one flange is attached rigidlv to the casing to serve as back-up for the gasket While tile other flange is movable. To date, these gasket seal rings have been field-tested in 27 Wells. Althotrgh communication has been noted in two wells, inter-zonal flow has been prevented in other wells in the same area by installing more seal rings between the communicaring zones. INTRODUCTION The inter-zonal flow of fluids behind casing cemented in oil wells during normal production or stimulation operations is a major operating problem. If it cccurs during production operations. it can seriously limit the pressure to which a reservoir may be depleted without harmful invasion of unwanted fluids. If it occurs during stimulation operations, it may preclude the possibility of stimulating the desired zone. This communication can be caused by failure of the bond between the casing and cement, failure of the bond between the cement and formation, or failure of the cement itself. This paper presents the results of an investigation of factors affecting com-munication at the casing-cement bond and methods which aid in preventing it. LABORATORY INVESTIGATIONS The laboratory tests performed in this study were divided into three phases. The first phase consisted of tests to determine if perforating would shatter and crack the cement sheath so severely that communication would occur through the cement itself. The second phase consisted of tests to determine more precisely the cause for the casing-cement bond failure. The third phase consisted of tests to evaluate the effectiveness of various de-formable seals attached to the casing in preventing communication. EFFECT OF PERFORATING, The effect of perforating was invest~gated in tests performed with apparatus shown on Fig. 1. Cement was poured into the annulur space hetween 5%-in. casing and 8%-in. casing and allowed to cure for 72 hours. The apparatus was then perforated with a hollow carrier gun containing eight duPont 26-A shaped charges. Bull plugs were placed over the perforations in the 8 5/8-in. casing and hydraulic pressure was applied inside the 5 1/2i-in. casing. The pressure to cause fluid communication past the cement sheath was observed and termed the "bond failure pressure". Several different cement compositions were included in these tests, the results of which are shown in Table 1. In Tests 1 through 4 of Table 1, bond failure occurred at- the inter- .

Jan 1, 1966

By H. W. McQuaid, E. W. Ehn

It is usually assumed that chemical specifications are sufficient for steel to be used for case carburizing, and if the steel analyzes within the ordinary limits specified for steel for this purpose, no difficulty traceable to the steel used should be encountered in obtaining satisfactory results in the case carburizing and hardening. Much work has been done to determine the effect of various alloying elements on the rate of carbon penetration, etc. but, to our knowledge, little if anything has been published in regard to the effeet of the quality of the steel on the final results in the hardening of case-carburized steel parts. The writers believe that the structure of the case both before and after quenching is greatly affected by the actual condition of the steel itself as made, and that for good results in the case-carburizing and hardening departments, the steel should be of the best possible quality as regards non-metallic impurities. It is the purpose of this paper to prove that the presence of excess dissolved oxides in the steel, as made in the melting furnace, affects permanently the results obtained in carburizing and hardening and that it is possible that the presence of dissolved oxide call result in total unfit-ness of low-carbon steel for case hardening purposes. When races and rolls for roller bearings are made from a low-carbon steel, case carburized and hardened, it is of primary importance that the results of this treatment be of the highest quality. It is necessary, therefore, that in the case-carburizing work each detail be rigorously checked to avoid any defects which would cause the loss of much time and material. The case carburizing with which this paper deals was done in under-fired oil furnaces. The temperature of each furnace is controlled by means of a platinum platinum-rhodium thermocouple, in connection with a potentiometer indicator and potentiometer recorder. The temperature of each furnace is registered every 15 min. by an operator, who is continually checked by the automatic recorders.

Jan 1, 1922

By H. W. McQuaid, E. W. Ehn

It is usually assumed that chemical specifications are sufficient for steel to be used for case carburizing, and if the steel analyzes within the ordinary limits specified for steel for this purpose, no difficulty traceable to the steel used should be encountered in obtaining satisfactory results in the case carburizing and hardening. Much work has been done to determine the effect of various alloying elements on the rate of carbon penetration, etc. but, to our knowledge, little if anything has been published in regard to the effeet of the quality of the steel on the final results in the hardening of case-carburized steel parts. The writers believe that the structure of the case both before and after quenching is greatly affected by the actual condition of the steel itself as made, and that for good results in the case-carburizing and hardening departments, the steel should be of the best possible quality as regards non-metallic impurities. It is the purpose of this paper to prove that the presence of excess dissolved oxides in the steel, as made in the melting furnace, affects permanently the results obtained in carburizing and hardening and that it is possible that the presence of dissolved oxide call result in total unfit-ness of low-carbon steel for case hardening purposes. When races and rolls for roller bearings are made from a low-carbon steel, case carburized and hardened, it is of primary importance that the results of this treatment be of the highest quality. It is necessary, therefore, that in the case-carburizing work each detail be rigorously checked to avoid any defects which would cause the loss of much time and material. The case carburizing with which this paper deals was done in under-fired oil furnaces. The temperature of each furnace is controlled by means of a platinum platinum-rhodium thermocouple, in connection with a potentiometer indicator and potentiometer recorder. The temperature of each furnace is registered every 15 min. by an operator, who is continually checked by the automatic recorders.

Jan 1, 1922

By Alec M. Crowell, J. W. Sanders

While the production of crude oil and condensate in South Arkansas increased only 1.7 per cent over the 1940 figure, complete utilization of gas produced with the oil and condensate, and heretofore wasted, was beginning to be evidenced. There were 26,229,264 bbl. of oil and condensate produced in South Arkansas during 1941, as against 25,790,380 bbl. for the year 1940. (Fig. I.) Since 1936, deep producing sands have been discovered in 18 fields and during that period only 40 per cent of the total state production has come from Upper Cretaceous formations while 60 per cent came from the Lower Cretaceous and Jurassic formations. The gas produced with crude oil and condensate from the latter formation contains large quantities of hydrogen sulphide, the maximum being 6900 grains per 100 cu. ft. in the Patton pool of Lafayette County. Gas Utilization During the latter part of 1940 and the early part of 1941, pilot plants were placed in operation to determine whether the hydrogen sulphide and deleterious material in South Arkansas gases could be removed economically. The Federal Government desired to build a large aluminum plant in the Ouachita Valley and was seeking cheap fuel for the generation of electricity. The fact that the gases were produced with appreciable quantities of crude oil and condensate made it available at a very low price, since the state's conservation law prohibits the flaring of any gas. As a result of these experiments the first large-scale unit for the processing of gases containing hydrogen sulphide was placed in operation on Sept. I, 1941. The plant is in the Magnolia oil field, Columbia County. It processes residue gas from the Shell Oil Company's gasoline plant in that field and also raw gas from the Village field, 6 miles east of the Magnolia field. The gas entering the desulphuri-zation unit is laden with approximately 1400 grains of hydrogen sulphide per 100 cu. ft. and is stripped to a content of 4 grains per 100 cu. ft. The capacity of the plant is 15 million cu. ft. of gas treated daily under a pressure of 160 lb. per sq. in. The cost of treatment, exclusive of depreciation, is appreciably less than I per 1000 cubic feet. Two other plants of much greater capacity have been announced and priorities have been granted, which should bring the total amount of gas treated to 150 million cu. ft. daily. The gas to be treated will have a maximum hydrogen sulphide content of 4500 grains per 100 cu. ft. and will be processed under a pressure of 600 lb. per sq. in. These developments are something entirely new in field practice for the industry. The fact that this heretofore wasted gas is available at very low cost has led to the location of some eight war industries within the state, in addition to the alu-minum plant. Recovery OF Sulphur The Susearch Corporation and the Southern Acid and Sulphur Co. placed in operation during 1941 pilot plants to de-

Jan 1, 1942

By Alec M. Crowell, J. W. Sanders

While the production of crude oil and condensate in South Arkansas increased only 1.7 per cent over the 1940 figure, complete utilization of gas produced with the oil and condensate, and heretofore wasted, was beginning to be evidenced. There were 26,229,264 bbl. of oil and condensate produced in South Arkansas during 1941, as against 25,790,380 bbl. for the year 1940. (Fig. I.) Since 1936, deep producing sands have been discovered in 18 fields and during that period only 40 per cent of the total state production has come from Upper Cretaceous formations while 60 per cent came from the Lower Cretaceous and Jurassic formations. The gas produced with crude oil and condensate from the latter formation contains large quantities of hydrogen sulphide, the maximum being 6900 grains per 100 cu. ft. in the Patton pool of Lafayette County. Gas Utilization During the latter part of 1940 and the early part of 1941, pilot plants were placed in operation to determine whether the hydrogen sulphide and deleterious material in South Arkansas gases could be removed economically. The Federal Government desired to build a large aluminum plant in the Ouachita Valley and was seeking cheap fuel for the generation of electricity. The fact that the gases were produced with appreciable quantities of crude oil and condensate made it available at a very low price, since the state's conservation law prohibits the flaring of any gas. As a result of these experiments the first large-scale unit for the processing of gases containing hydrogen sulphide was placed in operation on Sept. I, 1941. The plant is in the Magnolia oil field, Columbia County. It processes residue gas from the Shell Oil Company's gasoline plant in that field and also raw gas from the Village field, 6 miles east of the Magnolia field. The gas entering the desulphuri-zation unit is laden with approximately 1400 grains of hydrogen sulphide per 100 cu. ft. and is stripped to a content of 4 grains per 100 cu. ft. The capacity of the plant is 15 million cu. ft. of gas treated daily under a pressure of 160 lb. per sq. in. The cost of treatment, exclusive of depreciation, is appreciably less than I per 1000 cubic feet. Two other plants of much greater capacity have been announced and priorities have been granted, which should bring the total amount of gas treated to 150 million cu. ft. daily. The gas to be treated will have a maximum hydrogen sulphide content of 4500 grains per 100 cu. ft. and will be processed under a pressure of 600 lb. per sq. in. These developments are something entirely new in field practice for the industry. The fact that this heretofore wasted gas is available at very low cost has led to the location of some eight war industries within the state, in addition to the alu-minum plant. Recovery OF Sulphur The Susearch Corporation and the Southern Acid and Sulphur Co. placed in operation during 1941 pilot plants to de-

Jan 1, 1942

By Niels Hansen

The substructure formed by drawing at room temperature in aluminum (99.5 and 99.998 pct purity) and in recrystallized aluminum aluminum-oxide products containing from 0.2 to 4.7 wt pct of aluminum -oxide was examined by transmission electron microscopy, and the flow stress of the drawn materials was measured by tensile testing at room temperature. A sub-grain structure was present after a reduction in area by drawing of 10 to 20 pct, and the subgrain size was observed to decrease with increasing deformation. The tensile data show that the increase in flow stress (0.2 pct offset) by drawing from 10 to 95 pct depends on the reduction in area, not on the composition of the materials. Dispersion strengthening and subgrain bowzdary strengtlzening contribute to the flow stress, and these strengthening processes have been found to be linearly additive. The flow stress (0) can be related to the subgrain size &) by the Petclz relation = uo + k . t, where go is dependent on the composition of the products and k is approximately the same far all materials. THE microstructure of dispersion-strengthened aluminum aluminum-oxide products consists of small oxide plates distributed in an aluminum matrix. The matrix structure depends on the manufacturing history, and in hot-worked as well as cold-worked products the matrix is divided by subgrain (or dislocation) boundaries. For hot-extruded products it has been shown1 that dispersion strengthening and subgrain boundary strengthening are linearly additive, and the flow stress (0.2 pct offset.) at room temperature has been related to the subgrain size (ts) by a Petch equation,2,3 s = so + k . ts-1/2, where s0, increases with increasing oxide content. For cold-worked products containing subgrains no systematic work has been reported, and it was the aim of the present study to examine the microstructure and the relationship between the flow stress and the subgrain size for such products. The behavior of' aluminum aluminum-oxide products depends on the purity of the aluminum matrix, and aluminum of the matrix purity (99.5 pct) was included in the investigation. The literature contains few data about the behavior of this impure aluminum, and aluminum of a higher purity (99.998 pct) was therefore also examined. As regards the relationship between the flow stress and the subgrain size in cold-worked dispersion-strengthened products, no systematic work has been reported. For aged cold-worked structures containing fine precipitates (Fe-Mo carbide) a Petch relation has been found,4 and it has been shown that the k value NlELS HANSEN is Head, Metallurgy Department, Danish Atomic Energy Commission, Research Establishment Riso, Denmark. Manuscriot submitted January 9, 1969. IMD is approximately the same as in iron, whereas the s0 value is higher owing to the presence of the precipi-tates. Investigations of metals such as tungsten,' ferrous metals,4,6 and molybdenum7 cold drawn or swaged at room temperature have shown that the flow stress can be related to the subgrain size by a Petch relation when ts is taken as the subgrain size perpendicular to the direction of deformation. For aluminum no work has been reported on the relationship between the flow stress and the subgrain size after deformation at room temperature, whereas for aluminum tensile strained at different temperatures in the range -183" to 375°C a Petch relation has been found by taking ts equal to the subgrain size.' In the present study two aluminum materials (99.998 and 99.5 pct) and three aluminum aluminum-oxide products (containing 0.2, 1.0, and 4.7 wt pct oxide) were drawn at room temperature to reductions in area from about 10 to about 95 pct. The structures were studied by transmission electron microscopy, and the flow stress (0.2 pct offset) was measured at room temperature. EXPERIMENTAL Materials. The materials are given in Table I together with the chemical analysis. The three aluminum aluminum-oxide products were manufactured from aluminum powder that had been compacted and Table I. Chemical Analysis of Materials Al203 Fe SI Material wt pct wt pct wt pct 99.998 pct* - 0.0004 0.0012 Aluminum 99.5 pctt - 0.36 0.16 Aluminum AlMD13† 0.2 0.16 0.12 Aluminum- -Oxide AlMD105† 1.0 0.26 0.18 Products SAPISML960s† 4.7 0.22 0.19 *Other impurities: O.0004 pct max each of Cu and Zn (supplier's analysis). †Other impurities: 0.03 pct max Cu. 0.02 pct max each of Mn, Mg, Zn, Ti. Table 11. Mean Diameter of Aluminum-Oxide Particles in Extruded and in Cold--Drawn Aluminum Aluminum-Oxide Products Mean Diam. of A1203-Plates* Material State A AlMD105 Extruded 540 Cold Drawn 97 pct 510 SAP ISML 960 Extruded 770 Cold Drawn 95 pct 820 *The standard deviation of the mean is approx. 5 ±pct.

Jan 1, 1970

By C. H. Li, R. D. Carnahan, R. J. Stokes, T. L. Johnston

When silver chloride deforms by pencil glide at temperatures of 26ºand 72°C, grain size has no effect upon the proportional limit and the material necks down to a knife edge under tension. At -196ºC, deformation takes place on fewer slip systems to produce straight slip traces, the flow stress becomes sensitive to grain size and fracture occurs by cleavage from an intergranular source without any reduction in area. THERE are significant differences between the appearance of the slip bands formed in silver chloride and in the alkali halides at room temperature. The bands in sodium chloride, e.g., are fine and geometrically straight, whereas in silver chloride they are coarse and wavy.' Such differences in the slip behavior prompted us to inquire what the effects of grain boundaries might be on the mechanical properties of these solids. As an introduction to a general study of ionic poly-crystal behavior, we have investigated the effect of grain size on the stress-strain relationships in silver chloride at different temperatures. We have chosen silver chloride chiefly because polycrystals can be easily prepared free from cracks and macroscopic voids by conventional techniques. Moreover, as we shall see, the slip behavior can be readily modified by changing the temperature. It will be shown that the effect of grain size on the yield stress of silver chloride is strikingly dependent upon the temperature of deformation and that this temperature effect comes about through a change in the number of slip systems which operate at the onset of plastic flow. EXPERIMENTAL PROCEDURES Polycrystalline tensile specimens were made by recrystallizing cold-rolled AgCl sheet. Thirty-gram quantities of AR grade silver chloride powder were melted in a low heat capacity furnace, cast into cylindrical forms 3/4 in. in dim and approximately 1 in. in length and then extruded with a 16:l reduction ratio into rods 3/16 in. in dim. Extrusion temperatures were varied from room temperature to 350°C. In order to impart various degrees of cold'work to the extruded rod. All extrusions were then cross rolled to sheet 0.040 in. in thickness at room temperature and machined to form tensile specimens having a gage length of 0.750 in. with a width of either 0.250 or 0.145 in.* Annealing was carried out in an air oven at 200°C for periods up to 20 hr. specimens having average grain diameters ranging from 0.024 to 0.40 mm were prepared by varying the extrusion temperature and annealing time in the conventional manner. To obtain specimens with grain sizes larger than 0.40mm, lightly deformed thin prisims of silver chloride single crystals (supplied by Harshaw Chemical Co.) were recrystallized. Grain size determinations were made by an intercept method and revealed that the grains were equi-axed. Laue back-reflection X-ray patterns showed little tendency to form a preferred orientation texture. Specimens which were to be used for the slip band studies were polished by immersion in fresh boiling concentrated NH,OH for 60 sec. They were then etch polished for 10 sec on each side by hand lapping on a stationary velveteen lap wetted with a dilute Hypo solution (5 g of Kodak Acid Fixer in 100 cc H20). Finally the specimens were rinsed in warm water and alcohol, blown dry and carefully mounted in the tensile machine for testing. Tensile tests were performed at three temperatures, namely, 26º, -72º, and -196°C. A screw-driven hard tensile machine was used at a constant strain rate of 0.006 in. per in. per min. Loads were determined with a light- proof ring fitted with A-18 strain gages and extensions were measured with a 0.0001 in. dial gage. Constant level baths of alcohol with dry ice and liquid nitrogen were used to maintain the two lower test temperatures. EXPERIMENTAL RESULTS Reproducibility—In view of the light sensitivity and reactive nature of silver chloride, it was necessary to determine whether reproducibility depended upon either exposure to light or to the condition of the surface. However, during the course of the work it became clear that variation of laboratory lighting

Jan 1, 1962

Aamot, Olav Crone, Chem. Engr., Norsk Elektrokemisk, Kongensgt. 18, Olso. Norway. '29 Abadilla.-Quirico A., Dir., Bureau of Mines Manila, P. I. '38 Abbott, Clarence E., V.P., Charge of Raw Materials, Tennessee Coal, Iron & R.R. Co., 1212 Brown-Marx Bldg., Birmingham, Ala. '04 Abel, Raymond L., Prof., Dept. of Pet. Refin., Univ. of Pittsburgh Pittsburgh, Pa. '29 Abel. Walter D., Cons. Engr 1839 Holmby Ave., W. Los Angeles. Calif. '32 Abele, Louis T R. F. D. 5. Susquehanna Trail, N., York. Pa. '31 Abell, Leo M., Ore Dressing Investigator, School of Mines Adelaide, S. Australia. '31 Abenius. Hakan V., Mine Supt., Bolidens Gruvaktiebolag Boliden, Sweden. '37 Aborn, Robert H., Asst Met., Research Lab., U. S. Steel Corp. Lincoln Highway, Kearny, N. J. '19 Abraham, W. E. V., East India United Service-Club, 16 St. James' Sq., London, S. W. 1, England. '28 Abrams. Charles Jackson 1624 17th St., Denver, Colo. '36 Abstein, Henry T., Engr. & Mgr., Profile-Tamarack Mines Co Yellow Pine, Idaho. '27

Jan 1, 1938

By WILKES BARRE

AS PREVIOUSLY announced, the semi-centennial meeting of the Institute is to be held at Wilkes-Barre, Pa., on Sept. 12, 13, 14, and 15. An interesting program of technical sessions and excursions is now being prepared by the Local Committee. At the time of going to press the program had not been completed in sufficient detail to permit its being pub¬lished in this number. The detailed program will be published in the September MINING AND METALLURGY, which will be printed in time to be distributed before the Wilkes-Barre Meeting. It may be said in advance, however, that the Com¬mittee has progressed so far in its work that we are assured of one of the -most notable meetings the Insti¬tute has held and that members will miss a rare .treat if they do not attend. The many trips and excursions, as well as the banquet, will be -given to the members as a compliment from the members of the Local Com¬mittee. . . The paper by Howard Eavenson on the Lynch Plant of -the United States Coal and Coke Co. will be illustrated by lantern slides and moving pictures. One of the most appropriate discussions will be that opened by Prof. J. F. Kemp on the Stratigraphy of the Anthracite Region; this also will be amply illustrated.

Jan 1, 1921

IN accordance with a programme arranged by a committee of the Institute, consisting of Mr. William P. Shinn, of St. Louis, chairman, and Mr. Joseph D. Weeks, of Pittsburgh, secretary, the member's of the Institute, with their ladies and invited guests, assembled in Chicago on Sunday morning, August 22d. A special train, provided by the Chicago and Northwestern Railway,. left Chicago on Monday morning at 7.50 o'clock, and conveyed the party to Marquette, arriving at 9 o'clock P.M. Here the steamer Northern Queen, which had been chartered by the committee for the accommodation of the Institute, was in waiting, and the members and ladies at once took up their quarters on the boat. EXCURSIONS IN THE MARQUETTE IRON REGION. Local Committee. EXECUTIVE. -J. C. Morse, chairman; C. Y. Osburn, secretary ; D. F. Wadsworth, treasurer; C. H. Hall, H. Merry. RECEPTION.-S. P. Ely, J. P. Pendill, E. Breitung, W. F. Swift, A. P. Swineford, J. C. Fowle, C. G. Griffey. TRANSPORTATION.-Samuel Schoch, D. Morgan, D. H.. Merritt, J. Pickands. FINANCE.-Peter White, A. W. Maitland, W D. Rees, E. R. Hall. EXCURSIONS.-W. E. Dickinson, H. A. Burt, A.. Kidder, C. E. Wright. REFRESHMENTS.-J. Q. Adams, H. H. Stafford, Joseph Kirkpatrick, D. H. Bacon. On Tuesday the iron mines in the vicinity of Negaunee and Ishpeming were visited, transportation being provided by special trains on the Marquette, Houghton and Ontonagon Railroad. In the morning the McComber, South Jackson, and Jackson mines were inspected, and in the afternoon the Cleveland, New York, Lake Superior, and Barnum mines. Dinner was provided at Negaunee, and gracefully served by, the ladies of the town. In the evening the first session of the Institute was held in the saloon of the steamer. The President, William P. Shinn, of St. Louis, congratulated the Institute on the happy consummation of the wishes of its members to have a meeting on Lake Superior. After tedious and baffling negotiations arrangements had been com-

Jan 1, 1881

By G. M. Crosby

Seven mines with important production records in the Coeur d'Alene lie adjacent to the Gem stocks —the Frisco (Gem), Hercules, Interstate, Rex (Sixteen to One), Success (Granite), Sunset, and Tamarack. Old records are incomplete, but available data given in Table I show these mines have produced 10.550,721 tons of ore containing more than 50 million oz of silver, more than 1.5 billion lb of lead, and about 1 billion lb of zinc (approximately 1.25 million tons of lead and zinc combined). Average ore grade is 4.8 oz of silver per ton, 7.2 pct Pb, and 4.6 pct Zn. This impressive production represents about 12 pct of the District's yield. At present metal prices, with modern beneficiation, the gross value would be more than $400 million. THE GEM STOCKS The Gem stocks, considered to be outliers of the Idaho batholith of Late Cretaceous age, are located in the northern half of the Mullan quadrangle, and extend from the town of Gem, Idaho, along a strike of N30°E for a distance of approximately five miles. They occur as two major masses of monzonitic rocks commonly referred to as the North stock, which covers an area of 1.1 sq miles, and the South stock, which covers 2.6 sq miles. The areal pattern is roughly club-shaped, the North stock representing the handle and the South stock the head of the club. Two and a half miles west and five miles northeast are two groups of smaller stocks, isolated from the main masses but of the same general rock type. This discussion is limited for the most part to the North and South stocks. At the north end, where the intrusion is about 3200 ft wide, the walls are about parallel and dip very steeply west. At the south end, where the mass is about 7000 ft wide at surface, the walls dip away from each other at moderately steep angles. An aeromagnetic survey' detects and outlines with surprising accuracy the two main stocks. as illustrated on the magnetic contour map (Fig. 2). Of particular interest is the location and shape of the magnetic anomaly representing the South stock. The anomaly is centered over the south end of the outcrop, and a westerly extension joins it with a smaller anomaly over the Dago Peak stocks. The latter anomaly, likewise, is located over the south end of the isolated stocks. This pattern suggests the intrusion has greater extent at depth to the south and west. Though correlation between the Dago Peak stocks and the larger masses is suggested, the controversial aspects of the Dobson Pass fault, which separates the two areas, casts doubt on a correlation. Topographically the monzonite stocks are ignored by the drainage pattern indicating these rocks, and the invaded rocks of the Lower Belt Series react similarly to erosion. The drainage patterns of Nine Mile and Canyon creeks cut indiscriminately across the monzonite-Belt contact, resulting in both valleys and ridges in the southern end of the intrusion. Nine Mile Creek traverses diagonally the entire five-mile length of the stocks. The monzonite rocks of the intrusion are referred to locally as granite, but granite is rare and the rocks comprise a wide variety of types. Their characteristics, described in detail by F. L. Ransome and F. C. Calkins,' are summarized by P. J. Shenon.' The principal rock type is coarse-grained, light gray, porphoritic monzonite containing black crystals of hornblende. Pyroxene, epidote, and titanite

Jan 1, 1960

By L. H. Schwartz, S. K. Lahiri, M. E. Fine, D. Chandra

WHILE the yield stress of solution treated Fe-Cu alloys increases rapidly with aging, a precipitate has only been directly observed in overaged samples.'-" This precipitate is essentially pure fcc copper, the E phase. Hornbogen2 suggested that the initial hardening is due to clustering of copper atoms in a bcc iron matrix. Hornbogen was not able to obtain direct confirmation for such bcc clusters by either X-ray diffraction or electron microscopy; however, he did observe analogous clustering in Fe-Au alloys7 where the scattering factor difference between iron and gold is more favorable than that for iron and copper. Fujii, Nemoto, Suto, and Monma4 recently observed diffuse electron diffraction scattering in a 2.5 pct Cu alloy aged at 500°C: for 30 hr. They suggested that part of the diffuse SCattering was due to a modulated structure of 26 to 42 wavelength parallel to the (110) matrix plane. This disappeared with further aging. However, 30 hr at 500°C is well beyond the peak strengthening in this alloy which occurred at less than I hr at 500oc.4 By transmission electron microscopy they could not distinguish between quenched samples and samples aged to maximum strength. The purpose of the present investigation was to try to obtain further confirming evidence for a precipitation stage preceding the formation of the fcc E phase. Change in Young's modulus was selected for study be- EXPERIMENTAL PROCEDURE The Fe-1.67 at. pct Cu alloy was supplied by the U.S. Steel Corporation in the form of a hot forged rectangular bar. The carbon and nitrogen contents of this alloy were 70 ppm and less than 10 ppm, respectively. The samples for Young's modulus measurements were made by cold swaging to & in. diam and cutting to 2 in. lengths. Tensile test samples 1 in. long were prepared by cold rolling to a thickness of 0.012 in. and then machining to gage dimensions of 0.5 by 0.012 in. For Mijssbauer studies, foils 1 mil thick were prepared by cold rolling. During fabrication the alloy was given intermediate anneals at 845OC followed by quenching. The specimens after preparation were solution treated at 1000°C (y field) or 845°C (a field) for 1 to 2 and 5 to 6 hr, respectively, in a dynamic vacuum of about 2 x lom6 torr. The tensile and modulus specimens were drop-quenched into iced brine through an aluminum foil which vacuum-sealed the bottom of the furnace tube. The MOssbauer foils were drop-quenched into helium gas cooled by passing through N2 (liq) in a copper coil. The grain diameter of the modulus and tensile specimens was between 0.025 and 0.035 mm. The samples were aged from 400" to 500°C in a dynamic vacuum of 2 x 10-6 torr and cooled by pulling into a water-cooled portion of the vacuum system. The dynamic Young's modulus was measured at room temperature using electrostatic excitation and detection of longitudinal vibrations.' Neglecting any length change during the aging, (this is expected to be comparatively small), the fractional change of Young's modulus (?Et)/Eav, is equal to twice the fractional change of the resonant frequency (?ft)/fav . ?ft =ft —fo where fo and ft are the resonant frequencies of a specimen before aging and after aging to time t. The measured f's, approximately 51,000 cps, were corrected to 25°C for any variation in the ambient temperature. The tensile tests reported were carried out at room temperature in an Instron with a 1000 lb full scale load cell. The flow stress reported herein corresponds to a strain of 0.002. The Massbauer spectra were taken in a constant acceleration model AM-1 NSEC spectrometer. The

Jan 1, 1970

By Nicholas J. Grant, W. Michael Yim

The creep-rupture properties of nickel, in as-prestrained or prestrain-polygonized condition, were studied at 1300°F and 4000 psi, and also at 700°F and 26,000 psi. An improvement of strength was noted in both the as -prestrained and the prestrain-polygonized tests at each temperature. The as-prestrained tests, however, showed superior creep resistance to the prestrain-polygonized ones. From the results of X-ray and etch-pit studies, the strengthc gain was interpreted in terms of dislocation density and the stability of preformed substructures. COLD work is known to improve the strength properties of metals at low temperatures. At high temperatures, however, the strength improvement is often lost if gross structural changes, such as re-crystallization, take place prior to or during the test. Even in the absence of recrystallization, a prestrained metal may undergo structural changes— polygonization and the formation of well-defined subgrains—which importantly effect the resultant properties. The relationship between substructure and creep properties has received considerable attention in recent years. The work of wood1 indicated that the creep strength of aluminum and its alloys was closely related to the subgrain size. Hazlett and Hansen,2 and Ancker, Hazlett, and parker,3 working with nickel and nickel alloys, had shown that small amounts of prestrain at room temperature followed by a recovery anneal at 800°C (1470°F) improved the strength at both low and high temperatures. The strength gain was attributed to an increase in the number of subgrain boundaries as a result of the prestrain-polygonization treatment. More recently Coldren and Freeman4 studied the effect of substructures on the creep rate of nickel at 1550°F. Their conclusions indicated that the substructure size as measured by the number of boundaries was the factor that controlled the creep rate. In addition, the perfection of the subgrain boundary has been indicated to have an important role on the strength.' On the other hand, there are data which disagree with the above observations. Grant, Chaudhuri, Silver, and Ganow6 found no creep strength improvement by a prestraining treatment. In reviewing the role of subgrains on high-temperature creep, Shepard and Dorn7 concluded that the contribution of the subgrains to high-temperature creep strength was a minor one. Guard,8 in a recent study on poly-gonized nickel, has cast doubt on the validity of the postulate that subgrain size controls the creep rate. In the majority of the previous studies, the subgrain boundaries have been singled out as the most important factor in determining creep strength; however, there is no firm theoretical ground for the postulate that the subgrain boundaries act as effective barriers to dislocation motion.B910 Little effort has been directed toward the study of the relationship between creep strength and other structural variables, such as dislocation density, lattice strain,

Jan 1, 1963

By Ernest Lilley

WHILE American scientific literature contains much information upon geologic conditions controlling the production of oil in Rumania, copper in Chile, and other fuel and metallic resources in many foreign countries, it is singularly lacking in data about the nonmetallics outside of the United States. Thus, though the United States is the outstanding market for European high-quality refined kaolin, and for the chinaware, porcelain, and other products of the European ceramics industries, Amer-ican literature contains only the briefest references to the deposits from which the raw kaolin utilized is obtained. To the writer, to whom has come in the past year .the opportunity of visiting a number of these deposits personally, they have proved of extreme interest both com-mercially and geologically. It is the latter phase that is discussed in this paper. The older and now largely crystalline rock areas of France, Germany, ;end other parts of western Europe contain numerous pegmatite dikes of which the upper portions have been subjected to surface weathering and kaolinization in much the same way as those of the eastern portion of the United States. Like the latter, the European pegmatite kaolins have long been known for their freedom from iron and other impurities offensive to the china and porcelain manufacturer. Unfortunately, they are also, like the American deposits, individually of small size and noted for their high costs of production. Deposits of sedimentary clay similar in many respects to the high-quality sedimentary kaolins of Georgia and South Carolina are known and worked, notably in southern Germany and in the Newton Abbott district of Devon and Dorset. in England. In general, their relationship to the parent rock from which they were derived is more evident than in the United States and the individual deposits are of smaller areal extent and less regular in outline.

Jan 1, 1932