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The Office of Price Stabilization broke the copper price loggerhead between the U. S. and Chile when it permitted copper wire and brass mills to add to their ceiling prices 80 pct of the increase in cost of foreign copper above the 27 1/2 cents per pound specified in the agreement with Chile. Another step forward in the processing of taconite seems to have been made with the patenting of a process for the strengthening of taconite pellets. The patent was issued to Fred D. De Vaney and assigne to the Erie Mining Co., of Hibbing, Minn. Strength of the pellets is improved by adding from one to five pounds of starch or sodium silicate. A new iron ore deposit discovered on Vancouver Island will start producing soon, and is expected to yield 2 million tons of magnetite over its span of operation. A new mill will be built by the Argonaut Construction Co., of San Francisco, at the deposits of the Utah Construction Co., its parent organization. The Organization for European Economic Cooperation banned the use of nickel and nickel alloy in the manufacture of about 500 products in an attempt to conserve nonferrous metals in short supply. Some 18 members of the organization have already volunteered to restrict nickel consumption.

Jan 1, 1952

By W. B. Potter

THERE is probably no more interesting group of mineral fuels to be found in any country than that occurring within the limits of the new State of Colorado. The supplies are so abundant, and the occurrence and distribution are so favorable for easy development and transportation to the future manufacturing centres of the State, that they are destined to play a very important part in the material growth and prosperity of the region, the more so because of the rich and varied stores of ores awaiting metallurgical treatment, and the comparative scarcity of timber for fuel. From a purely scientific point, also, these lignitic coals form an interesting and important series. An examination of their geological occurrence and relations opens up new and important questions regarding the comparative value of various kinds of geological evidence, while a study of the character and composition of this class of fuels, which forms a connecting link, as it were, between the lignites and the true bituminous coals, may lead to a more thorough and accurate classification of mineral fuels. The analyses here presented are from samples, of not less than fifty pounds each, obtained by myself during the summer of 1875, and may be regarded as representing very fairly the average run of

Jan 1, 1877

Sept. 3-8, AIME, Fall Meeting, Industrial Minerals, Minerals Beneficiation, Mining, Geology, & Geophysics, Iron and Steel, and Coal Div., Palmer House, Chicago. Sept. 3-13, AIME, Chicago Section, Centennial of Engineering, Chicago. Sept. 5-8, Engineers' Council for Professional Development, annual meeting, Hotel Sheraton, Chicago. Sept. 11-13, American Institute of Chemical Engineers, Palmer House, Chicago, Ill. Sept. 13, Columbia Section, AIME, Canadian Institute of Mining and Metallurgy, joint all-day meeting, Metaline Falls, Wash. Sept. 18, AIME, Utah Section, Newhouse Hotel, Salt Lake City. Sept. 20, Colorado Section, AIME, Denver. Andrew Fletcher, speaker. Sept. 22-25, American Mining Congress, Metal and Nonmetallic Mining Convention and Exposition, public auditorium, Denver. Sept. 23-25, Institution of Mining and Metallurgy, symposium on mineral dressing, Royal School of Mines. London.

Jan 1, 1952

By H. E. Rorschach

Activity in the oil and gas fields of Oklahoma was more pronounced in 1935 than in 1934, with 2320 completions, an increase of about 21 per cent. The state produced approximately 185,000,000 bbl. in 1935. Osage County and shallow pools in northeastern Oklahoma showed considerable activity. The assembly of a complete table of the oil fields of the state (Table 1) was not achieved, as many of the early records of operators and pipe line companies are not complete, and data for the older fields will perhaps never be fully tabulated. Table 1 includes all of the new fields and most of the important fields of the State of Oklahoma. Increased Field Activities The discovery of large production in the deep Simpson group in the old Fox field in Carter County in the southern part of the state, the discovery of new producing horizons in the Fitts pool, and the extension of Wilcox production in the "Mansion" area at Oklahoma City were the outstanding developments in Oklahoma in 1935. Wildcatting resulted in the discovery of new pools such as Jesse, Hoyt, Grayson, South Keokuk, Wofford, Britton and Stillwater. The Fitts and Edmond pools were rapidly developed during the year. Fox Pool.—Deep production in southern Oklahoma became a reality in October when the Williams No. 1 well of Carter Oil Co. and others, in the Fox pool, began producing oil at the rate of 10,000 bbl. per day from a depth of 8088 ft. After flowing wild several days, the well was killed after pipe stuck and a difficult fishing job resulted. The job had not been completed at the end of the year 1935. This test, considered one of the most important oil discoveries in the Mid-Continent area, opened the entire South Oklahoma area to a deep exploration campaign for Simpson production and production in the Pennsylvanian series on the south flank of the Arbuckle Mountains.

Jan 1, 1936

By H. E. Rorschach

Activity in the oil and gas fields of Oklahoma was more pronounced in 1935 than in 1934, with 2320 completions, an increase of about 21 per cent. The state produced approximately 185,000,000 bbl. in 1935. Osage County and shallow pools in northeastern Oklahoma showed considerable activity. The assembly of a complete table of the oil fields of the state (Table 1) was not achieved, as many of the early records of operators and pipe line companies are not complete, and data for the older fields will perhaps never be fully tabulated. Table 1 includes all of the new fields and most of the important fields of the State of Oklahoma. Increased Field Activities The discovery of large production in the deep Simpson group in the old Fox field in Carter County in the southern part of the state, the discovery of new producing horizons in the Fitts pool, and the extension of Wilcox production in the "Mansion" area at Oklahoma City were the outstanding developments in Oklahoma in 1935. Wildcatting resulted in the discovery of new pools such as Jesse, Hoyt, Grayson, South Keokuk, Wofford, Britton and Stillwater. The Fitts and Edmond pools were rapidly developed during the year. Fox Pool.—Deep production in southern Oklahoma became a reality in October when the Williams No. 1 well of Carter Oil Co. and others, in the Fox pool, began producing oil at the rate of 10,000 bbl. per day from a depth of 8088 ft. After flowing wild several days, the well was killed after pipe stuck and a difficult fishing job resulted. The job had not been completed at the end of the year 1935. This test, considered one of the most important oil discoveries in the Mid-Continent area, opened the entire South Oklahoma area to a deep exploration campaign for Simpson production and production in the Pennsylvanian series on the south flank of the Arbuckle Mountains.

Jan 1, 1936

By S. F. Bartram, G. A. Chase

COMPUTED X-ray diffraction powder patterns of YNi3, YNi5, and CbBe3 are available on request from either author.

Jan 1, 1968

By P. E. Doherty, B. Chalmers

Subboundaries may be revealed in aluminum by the formation of pits on the surface during cooling from elevated temperatures. The pits do not form in the vicinity of high- or low-angle boundaries. They are attributed to the condensation of vacancies from a super saturation produced during coolirzg. Using the vacancy pit and Schulz X-ray techniques for observing low-angle boundaries, a study was made of the transition from the nearly perfect seed to the striated structuke characterist-ic of aluminum crystals grown from the melt. It was found that the individual striation boundaries develop by the coalescence of very small-angle boundaries, as well as by the addition of individual dislocations. Several mechanisms for the formation of striations are discussed. Evidence was found suggesting that a super-saturation of vacancies exists near a growing interface, and it is proposed that the resulting climb of existing dislocalions produces "half'-loops" at the interface, which combine to form the low-angle striation boundaries. LINEAGE, or "striation" boundaries, have been studied in detail by Teghtsoonian and Chalmers 1,2 in crystals of tin grown from the melt, and by Atwater and Chalmers3 in lead. They found that single crystals grown from the melt consist of regions which are separated by subboundaries that lie roughly parallel to the growth direction. A difference in orientation of 0.5 to 3 deg exists between the striated regions; the misorientation is such that the lattice of one region could be brought into coincidence with the lattice of its neighbor by a rotation about an axis approximately parallel to the direction of growth of the crystal. They observed an incubation distance for the formation of striations which increased with decreasing growth rate. They also found that in any crystal, the sum of all rotations of the lattice in one sense, in going from one striation to the next, is very nearly equal to the sum of all the rotations in the opposite sense. A striation boundary, which is a low-angle grain boundary, can be described as an array of dislocations. If it is assumed that suitable dislocations are introduced into the crystal during solidification, the formation of striation boundaries can be explained as a result of the migration of the disloca- tions into arrays. The formation of arrays is energetically favorable since the energy of an assembly of dislocations can be reduced by the interaction of the stress fields when a suitable array is formed. This investigation presents and interprets new information concerning the nature and origin of striation boundaries in aluminum. EXPERIMENTAL TECHNIQUE Single crystals of high-purity aluminum (Alcoa 99.992 pct) were prepared by horizontal growth from the melt.'' The specimens were subsequently electropolished in a solution of 5 parts methanol to 1 part perchloric acid kept between -10° and 0°C in a bath of dry ice and alcohol. The current density was approximately 6 amps per sq in. Doherty and Davis9 have shown that in aluminum sub-boundaries with misorientations of not less than several seconds of arc may be revealed by the vacancy pit technique. During cooling from elevated temperatures pits form on electropolished surfaces of aluminum crystals as a result of the condensation of vacancies.11 Pits do not form in the vicinity of small- or large-angle grain boundaries, presumably because such boundaries act as sinks for vacancies. Boundaries of misorientations down to 3 sec of arc are revealed as pit-free regions, see Fig. 1. The Schulz X-ray technique12 was used to determine the angular misorientations of subboundaries. In this method, white radiation from a micro-focus X-ray tube is used to produce an image of a fairly large area of a single crystal surface. Subboundaries cause splitting in the diffracted image, see Fig. 2. Misorientations down to about 15 sec of arc may be observed with this technique. OBSERVATIONS AND DISCUSSION Figure 1 shows a striated aluminum crystal grown at 10 cm per hr etched by the vacancy pit technique. An incubation distance of about 1 cm is observed before the initiation of striation boundaries. Fig. 2 is a Schulz X-ray photograph of a striated crystal similar to that shown in Fig. 1. A large area of the crystal was studied by means of a series of photographs. Fig. 2, which is a reflection from the (100) plane, included about the first 4 cm of crystal to freeze. There is an incubation distance of about 1 cm, and a distance of about 2 cm over which the angle of misorientation builds up to its final value of approximately one degree. Some twist component can be seen in Fig. 2 at the right side of the photograph. From Fig. 2 it can be seen that the sum of all rotations of the lattice in one

Jan 1, 1962

By Sumner M. Anderson

Any discussion of outside support to Latin American mineral industries must concede at once the pre-eminent role of U. S. industry and business. American capital has developed the great copper resources of Chile and Peru, the lead-zinc of Peru and Mexico, the bauxite of Surinam and Jamaica, the petroleum and iron ore of Venezuela. American consumers have provided the market for their products. U. S. companies operating south of the border have trained Latin American geologists, engineers, chemists, and skilled labor-including metal, mineral, and fuel technicians-to new and greater competence. The industrial demands of World War II drastically altered world economics and concepts of U. S. foreign mineral requirements. In this country discovery of vital mineral resources fell far behind the alarming depletion rates, and there was new appreciation of the actual and potential importance of the world's less extensively explored areas. During the war and afterward, the task of supplying the nation's mineral requirements became greater than private industry could carry alone, and the Government assumed a position of continuing support.

Jan 11, 1958

By E. Buehler, E. Berry

HE magnetic properties of dilute palladium alloys are of fundamental interest.''' Neutron diffraction studies3 have indicated that a better understanding of the behavior of these alloys could be realized with the availability of high-purity single crystals of palladium. Crucible melts of 99.999 pct pure palladium were found inadequate for such research. In a successful effort to fill this need, floating zone refining of palladium was undertaken. In this note the results of the initial experiments are reported. Zoning was accomplished in an argon atmosphere using 450 kc rf generator for an energy source. Samples 5 to 6 mm in diam were suspended in a gastight quartz envelope which could be moved vertically through the rf coil. A nominal upward traverse rate of 1.5 mm per min was maintained during a pass. Close coupling was found to be essential for stable retention of the liquid in the zone. Single crystals averaging 3.5 cm in length were obtained. Laue photography showed them to be continuous single crystals without gross imperfections. Several criteria were used for evaluation of the purity of the zoned material: magnetic behavior, low-temperature specific heat and residual resistivity ratios. Table I shows the residual resistance ratios obtained for two samples, one subjected to a single pass, the other zoned four times. It is appilrent that palladium can be zone refined with the electrically active impurities being transported toward the tail end. A decrease in susceptibility for zone-melted specimens over any previously measured material from 1.5" to 80'~ has been obserted by H. J. Williams and R. C. Sherwood4 substantiating the residual resistance data. The specific heat measurements are currently being made3 and will be published at some later date. Discussions with J. H. Wernick and S. C. Abrahams are acknowledged. We also wish to thank G. F. Brennert for the residual resistance measure ments.

Jan 1, 1962

By W. G. Moffatt, J. Wulff

BRAZED joints and their strength have for some time been of great practical as well as theoretical interest. A good summary of the previous work in this field may be found in the reports of the Armour Research Foundation. In spite of excessive scatter in test data, the fact that the strength of a brazed joint may exceed the ultimate strength of the brazing material itself by many times continues to be of interest and of value in engineering. That this is qualitatively due to plastic constraint of the brazing material by the faying surfaces of the base metal is not in dispute, yet no complete interpretation of the data exists. The purpose of the present work is not to provide such a new interpretation, but to report new experimental data which we hope may lead to a better understanding of the important variables concerned. The work of Bredz' definitely shows that the thinner a brazed joint is, the greater is its strength. Dianeter of a joint has seldom been taken into

Jan 1, 1958

By W. D. Robertson, E. G. Grenier, V. F. Nole

The electrical, mechanical, and corrosion cracking properties of an age-hardenable Cu-Ni-Si alloy have been studied over a range of time, temperature, and deformation states for the purpose of determining the relationship between the properties and the structural state. The precifitate has been identi3ed as and the sites of preferred precipitation have been located by electron microscope studies of the structures developed by various combinations of heat treatment and plastic deformation. An extreme form of deformation banding has been observed in the aged alloy that results in high strain concentration in bands lying parallel to {111} planes. These bands are the structural paths along which transcrys-talline cracks propagate in the deformed alloy. The observations provide a basis for a general mechanism of transgranu-lar corrosion cracking of face-centered cubic alloys in terms of stacking fault probability. AMONG the age-hardening copper alloys the copper-nickel-silicon (Silnic Bronze) type is outstanding in exhibiting a high strength combined with a considerable capacity for cold working, a relatively high conductivity, and a low to negligible susceptibility to stress corrosion cracking. It is not a new alloy and it has been the subject of a number of investigations,1-5 which were made primarily to establish practical composition and heat treatment limits. The structural characteristics of the aging processes in this alloy have not previously been studied in detail. This particular investigation was undertaken to explore, in detail, and over a wide range of conditions, the properties obtainable by various combinations of working and heat treatment and to correlate structural changes with the observed mechanical, electrical and corrosion properties. MATERIAL AND PROCESSING Eight different commercial heats of the alloy were made and used in the investigation. The range of composition among the eight heats is shown in Table I. Billets, 8 by 24 in., were cast into water-cooled molds, extruded to 1.687-in. rod, and quenched in water after extrusion. Extruded material was rod rolled to 0.750 in., annealed at 1450° F for 2.5 hr, and quenched in water. Subsequent working operations were performed by tandem rolling to various sizes depending on the degree of reduction required. Final cold-working operations were performed by drawing to a uniform size of 0.187 in. diam and straightening by a roller straightening machine (Lewis). The combinations of heat treatment, working and aging that were investigated are summarized in Table 11; the various treatments were performed in the order given in each row of the table, and they will be subsequently identified by the symbols shown in the first column. SOLUTION TREATMENT All material investigated in the cold-worked condition, or cold worked prior to aging, was solution

Jan 1, 1962

By C. R. Holmgren

A large consolidated sand core was used in this investigation. Four groups of experiments including gas drives, water drives, and water drives combined with gas injection, were made. The results of the gas-drive experiments indicate that greater ultimate recovery may be obtained by higher pressure gradients. However, other considerations challenge the absolute veracity of this conclusion. Results indicate that with connate water present and a low pressure gradient during a gas drive, less gas is required to produce a given amount of oil. The saturation gradient determined during a gas drive is presented. Results of the water-drive experiments indicate that the recovery of oil is not a function of either gradient Or input rate. The presence of initial gas saturation resulted in a slightly lower final oil saturation. Injection of sufficient gas to maintain the initial gas saturation during a water drive resulted in lower final oil saturation. Introduction With the demand for petroleum products reaching an all-time record high and the location and exploitation of new reserves becoming more difficult and expensive, the oil industry must look to more thorough and efficient methods of producing the petroleum already located. Much of the previous work along these lines is exploratory and suggests a more complete investigation. For example, a great amount of laboratory work has been done on flooding sands initially saturated roo pct with oil. Since sands saturated roo pct with oil rarely, if ever, exist in nature, and because the water content is a vital factor in the ultimate recovery from the sand, laboratory investigations on cores without water must be supplemented by comparable work on cores with water present.1'2 Other investigators have done a considerable amount of laboratory work using gas and water drives.3 Krutter and Day4 have reported results of investigations using cores saturated IOO pct with oil and have concluded that " the ultimate recovery obtained, using air drive, from a completely oil-saturated core depends on the pressure gradients used. The higher the pressure gradient, the greater will be the recovery until a certain Pressure range is reached above which the reward of increased recovery is much smaller for similar increments in pressure." Yuster and Day6 conclude that less gas and less time are required to produce a given quantity of oil at high pressure gradients than at low pressure gradients; they also conclude that an increase in the viscosity of the oil requires a proportionate increase in the gas needed for recovery. Their results indicate that the gas required to produce a given quantity of oil is greatly reduced by the presence of connate water. R. C. Earlougher2 concluded, based on results of water-flooding a large number of

Jan 1, 1949

By Rossiter W. Raymond

The extent to which the divining-rod is still used in this country for the detection of hidden treasure, mineral veins, or springs, is ' much greater than educated persons would be likely to suppose. For many years wells have frequently been located by its aid in New England, where the belief is widely extended among the farmers that in the hands of peculiarly gifted persons this instrument possesses special virtue. Large numbers of the oil wells of Pennsylvania

Jan 1, 1883

By R. B. Sudderth, C. R. Merigold

Greater, emphasis is being placed on recovering nickel from laterite ores by ammonia leaching techniques. New methods are required for lower cost, non-polluting techniques to separate more efficiently the metals of interest. Liquid ion exchange techniques meet these requirements with the added advantage of producing salable electrowon nickel cathodes at the plantsite. A complete solvent extraction- electrowinning process is described, including preliminary engineering and cost data for a typical plant producing 50 million pounds of nickel per year.

Jan 1, 1973

By E. C. Reed

Drilling operations in Nebraska during 1942 were reduced to approximately 50 per cent of the previous year's record. Forty- No new fields were discovered, but the Barada field was extended and developed. Deeper drilling in the Dawson field was disappointing in view of the high expectstions held for the Viola, but some small Viola production did result, the first from

Jan 1, 1943

By E. C. Reed

Drilling operations in Nebraska during 1942 were reduced to approximately 50 per cent of the previous year's record. Forty- No new fields were discovered, but the Barada field was extended and developed. Deeper drilling in the Dawson field was disappointing in view of the high expectstions held for the Viola, but some small Viola production did result, the first from

Jan 1, 1943

By John N. Hobstetter

IT is widely believed that the nucleation of phase transformations in solid metals is accomplished by some type of local atomic fluctuations in the parent phase which arise from spontaneous diffusion in the metal or alloy system. Under appropriate conditions, these fluctuations are believed to be stable in the sense that the free energy of the entire system is lowered if the fluctuations, or nuclei, grow,' Under other conditions they are thought to be unstable in the sense that the free energy is lowered if they redissolve. The criterion for stability is usually taken as the size of the fluctuation. This view has been rationalized by Becker1 in terms of the free energy released by the volume of the nucleus and the free energy associated with the formation of a new surface surrounding the nucleus. The qualitative result of this reasoning is shown in Fig I where the changes in free energy for the surface and volume effects are plotted together with their sum against the radius of the nucleus. There is evidently always a critical size r. beyond which the release of free energy which is proportional to the volume always dominates the increase of free energy which is proportional to the surface area. Borelius2 has also attempted to rationalize the stability criterion for binary alloys, but in terms of the internal concentration of the fluctuations. He has found that, if surface energies are entirely ignored, the fluctuation must still reach a critical concentration if it is to become stable and avoid subsequent dilution. Although the Borelius theory fails to predict many observed nucleation phenomena such as the vanishing of the nucleation rate at the critical temperature, the major premise must certainly be valid. In this paper a reconciliation of the Becker and Borelius views is made by means of a search for nuclei which are at once stable with respect to both size and internal concentration, The increase in free energy per mole accompanying the formation of a nucleus which is just stable, ?fe, is independent of the path whereby the nucleus is brought into being. It is thus appropriate to seek critical nuclear attributes without reference to the fluctuation mechanism. The rate of nucleation, however, cannot be treated without a detailed understanding of the exact fluctuation process which produces stable nuclei. In this and succeeding papers the purpose will be to find the size, shape and internal concentration of the stable nucleus which is formed with a minimum increase in free energy in a wide variety of systems. THE NATURE OF THE NUCLEUS It is necessary to have rather detailed knowledge of the nature of a nucleus if ?Fe is to be computed. Fortunately, enough facts are known or suspected about the nucleus to make possible a detailed analysis. X ray diffraction studies have shown3

Jan 1, 1948

By E. C. Bitzer

The primary object of the work described in the following pages was to simplify the equipment in the separating circuit of the heavy-media process by substituting a spiral classifier for the separatory cone. Mechanical considerations were the leading attraction and the best that was hoped for on metallurgical performance was that the new vessel would give results equal to those obtained by conventional equipment. Tests have demonstrated in commercial operation on iron ore that the mechanical advantages of the spiral separator are about as predicted; also, the metallurgical performance is superior to the cone on the ores treated. Treatment of iron ore involves the separation of two products: a concentrate that sinks and a float product that contains true float material plus a controlled division of interfering middling. The middling material is heavier than the average specific gravity of the separating medium. Recent work with the spiral separator on Tri-State zinc ore showed that the middling material had to be recovered as concentrate because this fraction contained the bulk of the zinc in the ore. It has been demonstrated that it is possible to make three products with the new separator on an ore such as this: a float tailing, a float middling, and a high- grade heavy sink product. It appears from this last work that the new separator has definite mechanical and metalluigical advantages over any type of separating cone for treating feed that contains large amounts of material of a specific gravity close to that of the separating medium. However, either type of separator should perform equally well, metallurgically, on feed that is free of middlings. Each series of experiments with the spiral separator has required additional work to fully develop the possibilities of the machine. For this reason the paper is divided into chronological parts. History of Development A drag-type classifier was first proposed as a substitute for the cone separator by Butler Brothers technicians during the initial tests with galena medium at Crosby, Minn., in 1937. The desire for finding a substitute for the cone arose from trouble with interfering middlings and certain operating disadvantages of the cone. The possibility of using a spiral classifier was also suggested at this time by Emmett Butler and C. J. Abrams. However, inability to satisfactorily recover fine galena, which was used as a medium, terminated all development work at Crosby. During the winter of 1937--1938 investigation started on magnetic medium with concurrent development of the inverted or closed-top cone, which was found necessary to eliminate iron-ore middlings with the float product. About

Jan 1, 1949

By Frank Foote, E. R. Jette

In recent years the constitution of the high-silver aluminum-silver alloys has been extensively investigated. Hansenl has reviewed the literature to 1935. More recently, Obinata and Hagiya,2 Hofmann and Volk,3 Taziri4 and Tishchenko5 have confirmed the general features of the phase diagram in the region around 25 atomic per cent aluminum. In this paper we present the results of high-precision measurements of lattice constants of the silver-rich alpha solid solution in the homogeneous range and the neighboring two-phase regions. These results are used to establish the nature of the solid solution, the identity of directly measured densities with those calculated from lattice constants and the homogeneity limits of the alpha solid solution with respect to three different neighboring phases. A study of the earlier investigations indicated that the last two subjects in particular required new and accurate data. Experimental Procedure Preparation of the Alloys.—The alloys were made from high-purity silver and aluminum. The silver was "Proof Silver," 99.999 per cent pure, supplied by the U. S. Metals Refining Co. The aluminum was 99.97 per cent pure (contained Si, 0.009 per cent; Fe, 0.0016 per cent; Cu, 0.004 per cent) and was supplied by the Aluminum Company of America. The lattice constants of these two materials have been reported by Jette and Foote.6 Weighed amounts of the two metals were placed in alundum crucibles and melted in vacuo in a high-frequency induction furnace. The melts were allowed to cool in the crucible, the ingots thus obtained weighed about 10 grams. These ingots were then filed clean, hamered, again cleaned and given a homogenizing anneal in vacuo of from 6 to 15 days at temperatures ranging from 500" to 695°C. The ingots were air-cooled from the annealing temperature. Lattice-constant Measurements.—Carefully prepared filings for X-ray analysis were sealed into evacuated quartz or Pyrex tubes and annealed for various periods of time at suitable temperatures. The furnaces used were vertical, rapid-quenching furnaces, the samples being quenched by crushing the sample tube under water by means of a heavy plunger. The general X-ray technique has been previously described6 The cameras were of the symmetrical, back-reflection, focussing type. Ka, radiation from a cobait-nickel alloy target was used. The wave-length values were taken from the second edition of Siegbaum's book.7 A correction for the index of refraction was applied and the lattice constants were calculated by the method of Cohen.8, 6 The lattice constants were calculated to a common temperature of 25°C., using the value of the linear expansion coefficient of pure silver as 18.9 X 10-6. Presumably the expansion coefficient for

Jan 1, 1941

By Frank Foote, E. R. Jette

In recent years the constitution of the high-silver aluminum-silver alloys has been extensively investigated. Hansenl has reviewed the literature to 1935. More recently, Obinata and Hagiya,2 Hofmann and Volk,3 Taziri4 and Tishchenko5 have confirmed the general features of the phase diagram in the region around 25 atomic per cent aluminum. In this paper we present the results of high-precision measurements of lattice constants of the silver-rich alpha solid solution in the homogeneous range and the neighboring two-phase regions. These results are used to establish the nature of the solid solution, the identity of directly measured densities with those calculated from lattice constants and the homogeneity limits of the alpha solid solution with respect to three different neighboring phases. A study of the earlier investigations indicated that the last two subjects in particular required new and accurate data. Experimental Procedure Preparation of the Alloys.—The alloys were made from high-purity silver and aluminum. The silver was "Proof Silver," 99.999 per cent pure, supplied by the U. S. Metals Refining Co. The aluminum was 99.97 per cent pure (contained Si, 0.009 per cent; Fe, 0.0016 per cent; Cu, 0.004 per cent) and was supplied by the Aluminum Company of America. The lattice constants of these two materials have been reported by Jette and Foote.6 Weighed amounts of the two metals were placed in alundum crucibles and melted in vacuo in a high-frequency induction furnace. The melts were allowed to cool in the crucible, the ingots thus obtained weighed about 10 grams. These ingots were then filed clean, hamered, again cleaned and given a homogenizing anneal in vacuo of from 6 to 15 days at temperatures ranging from 500" to 695°C. The ingots were air-cooled from the annealing temperature. Lattice-constant Measurements.—Carefully prepared filings for X-ray analysis were sealed into evacuated quartz or Pyrex tubes and annealed for various periods of time at suitable temperatures. The furnaces used were vertical, rapid-quenching furnaces, the samples being quenched by crushing the sample tube under water by means of a heavy plunger. The general X-ray technique has been previously described6 The cameras were of the symmetrical, back-reflection, focussing type. Ka, radiation from a cobait-nickel alloy target was used. The wave-length values were taken from the second edition of Siegbaum's book.7 A correction for the index of refraction was applied and the lattice constants were calculated by the method of Cohen.8, 6 The lattice constants were calculated to a common temperature of 25°C., using the value of the linear expansion coefficient of pure silver as 18.9 X 10-6. Presumably the expansion coefficient for

Jan 1, 1941