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By R. K. Datta

Eluropium -activated yttrium vanadate, excited by short- and long-wavelength ultraviolet radiations, shows enzission lines near 6100A, the principal ones correspondirzg to transitions of EU+3 ions from 5Do to the F2 energy level. The ~neclmlallistns of absorption and etnissiorz of this phosphor have been empirically studied. The absorption is caused by two separate processes in the matrix. The phosphor YVO4:Eu and tlie matrix YVO, haue essentially the same resectance spectra in the region 2500 to 4000if. There are two broat ah~o?~ption bands: natnely, around 2600 and 3600A regions. Whet? compared with the reflectance spectra of the constituent oxides, namely, Y2O3, V205, Eu2 03, the absorption bands of the tnatvix and the phosphor in the short- and long-wavelength ultraviolet regions can be interpreted as due to charge-transfer processes involving i) Y-O and ii) 17-0, respecti~~ely. The excitation spectrum' of the phosphor has two broad bands with peaks at about 2600 and 3600A regions. U can be postulated that enevgy absorbed under short- crud long-wavelength ultraziolet excitatzon, respectzcely, by Y-0 and V-O parts of the niatrix is transferred by radcatio~zless process to EU+3 ions. Thzs postulate can empirically be proved on the basis of the spectra of the systems (YVO4,-YPO4,):Eu. PO? ~ons do not have' any appreciable absorption in the short or long uv regions. When P0't3 ions are substitlited for v0i3 ions in YVO,:Eu phosphors, the absorption and excitation in the lo~zg uv region are gradually reduced. Ailoreover, the £«+3 emission under 3650A excitation is decreased zuitlz increase in PO^ content, lt~lzereas the emission under 253711 excitation remains esserztially constant with as IILUCIL as 60 mole pct of YPO, in YVO,:En. EUROPIUM-activated yttrium vanadate (YV04:Eu) is a well-known phosptor.'-3 When excited by cathode rays, 2537, or 3650A radiations, YV04:Eu emits typical narrow-band spectrum of EU'3 fluorescence in the region of 5900 to 7100A, a very strong maximum occurring at about 6190A. This emission is considered to be due to 5Do — 7F2 transition of excite: EU*3 in 4f state. Moreover, the emission under 3650A excitation increases with temperature markedly. Because of these properties, YV04:Eu phosphor finds wide application in industries, namely, in color television tube, laser, and high-pressure mercury-vapor lamps. It is the purpose of this paper 1) to present the empirical study of the mechanism of absorption and excitation of YV04:Eu phosphor by ultraviolet radiation, and 2) to offer an explanation for the process of emission. It should be mentioned that a theoretical discussion on the mechanism of absorption in terms of the crystal or ligand field theory is beyond the scope of this paper. Empirical studies presented here are based primarily on spectroscopic and crystal-chemical investigations. EXPERIMENTAL i) Preparation of Materials. The synthesis of vanadate phosphorinvolves preparation of (Yi-.tEuj^Oj, blending the mixed oxide with an oxidic compound of vanadium, such as V205 or NH4V03, and firing the mixture at about 1000°C for several hours when YVO4:Eu forms as a primary phase. (Y1-xEux)203 compositions are prepared by coprecipitation of oxalates, and igniting them at about 1000°C. The vanadium compound is added in excess of the stoichiometric proportion for fluxing purposes. The charge is cooled, ground, and the excess of vanadium is removed by a hot wash (-80°C) of alkali or ammonia. Y(VP)04:Eu samples are prepared by mixing (Yi-xEux)203 with stoichio-metric proportions of (NH4)2HP04 and the vanadium compound. The mixtures are prefired at 700" to 800°C for 1 or 2 hr, then ground and refired at 1150°C. The firings of the phosphors are done in silica crucibles, and the homogeneity of the final products checked by X-ray diffraction analysis. ii) Spectroscopic Measurements. Diffuse reflectance sqectra of the samples within the range 2500 to 7000A are obtained by using CaF2 as standard in Cary Recording Spectrophotometer, Model No. 14. The emission spectra from phosphor plaques, excited under different ultraviolet sources, are obtained by a direct-recording spectroradiometer4 adapted with a grating monochromator with nearly constant dispersion. Maximym sensitivity in the spectral region from 2500 to 7000A is obtained with a quartz-windowed, S-20 response p$otomultiplier. The total' band pass is kept about 30A. The spectra are calibrated against the light from a standard tungsten filament lamp reflected from a magnesium-oxide plaque. Brightness data given throughout this report $re measured from the height of the main peak (6190A) of the emission spectra. The excitation spectra are measured using sodium salicy-late as standard. RESULTS AND DISCUSSION The diffuse reflectance spectra of both pure and activated YV04, along with their constituent components, are shown in Fig. 1. YVO4 shows two broad absorption bands, namely, around 2500 and 3600A, respectively. Since there is little difference between the reflectance spectraoof YVO4 and YVO,:Eu in the uv region (2500 to 4000A), it can be postulated that excitation of the phosphor is mainly due to absorption by the matrix, i.e., YVO4. The question, now, is whether the matrix (Yv04) is excited as a whole, or different components are responsible for the two absorption bands. The characteristic absorption spectra of molecular ions involving transition metal ions, both in aqueous solutions and in crystals, are due to electronic transi-

Jan 1, 1968

By V. G. Mooradian

THE diffusion of metal atoms into the crystal lattice of another metal and the assumption of regular positions to form a homogeneous alloy are some of the most fundamental phenomena of structural metallurgy. The mechanism of this process has been the subject of a great deal of study from many viewpoints, but the picture is still far from complete. It is generally believed that if one metal is to diffuse into another, the first must have some solubility in the second1. This means that the solvent must be able to accommodate the stranger atoms, either on points of its own lattice or in the interstices between, without losing its own crystal-lographic identity. It is also a general observation that cold-working is a distinct aid in the diffusion process, causing it to take place with greater rapidity at the same temperature or with the same speed at a lower temperature. There is considerable doubt, however, as to the real significance of the deformation in its effect on the diffusion mechanism. Several factors associated with the cold-working may be responsible for the increased diffusion rate. The plastic deformation causes a distor-tion of the solvent lattice, which may be an aid in the assimulation of atoms of another kind. There are many references2 in the literature that suggest that some distortion or "loosening" of the lattice is necessary for atomic migration and that diffusion cannot take place in the undis-

Jan 1, 1935

By Earl W. Palmer, Cyril Stanley Smith

A study of the precipitation-hardening of copper steels1 led the authors to investigate malleable iron containing copper, for the low-carbon ferritic matrix in malleable iron should lend itself admirably to precipitation-hardening. It was soon found that in addition to rendering malleable iron susceptible to improvement by precipitation-hardening treatments, copper has another potentially useful effect as an accelerator of graphitization. Brief mention of these effects was given in a general paper by Lorig and one of the present authors2; the present paper gives further details on the graphitization and precipitation-hardening effects only. After the completion of this work a paper by L. Lykkin3 appeared, confirming the authors' conclusions regarding graphitization. Material Used After some preliminary heats had been made in the laboratory to determine the effect of copper, several castings from commercial air-furnace heats were obtained, and data from these alone are given here. Part of the metal was poured directly and part was treated in the ladle with the desired amount of copper before pouring. Green-sand molds were used, each holding two tensile test pieces of the form adopted by the Malleable Iron Research Institute, or two bars for graphitization studies, 5/8 in, in diameter and 9 in. long, fed through two enlarged sections equidistant from the middle and ends of the bars. Risers of suitable size insured sound castings. Tensile tests were made on the castings after commercial mallealleizing and after special heat treatments to be described. The analyses of the white irons are given in Table 1.

Jan 1, 1935

By Cyril Stanley Smith, Earl W. Palmer

A study of the precipitation-hardening of copper steels1 led the authors to investigate malleable iron containing copper, for the low-carbon ferritic matrix in malleable iron should lend itself admirably to precipitation-hardening. It was soon found that in addition to rendering malleable iron susceptible to improvement by precipitation-hardening treatments, copper has another potentially useful effect as an accelerator of graphitization. Brief mention of these effects was given in a general paper by Lorig and one of the present authors2; the present paper gives further details on the graphitization and precipitation-hardening effects only. After the completion of this work a paper by L. Lykkin3 appeared, confirming the authors' conclusions regarding graphitization. Material Used After some preliminary heats had been made in the laboratory to determine the effect of copper, several castings from commercial air-furnace heats were obtained, and data from these alone are given here. Part of the metal was poured directly and part was treated in the ladle with the desired amount of copper before pouring. Green-sand molds were used, each holding two tensile test pieces of the form adopted by the Malleable Iron Research Institute, or two bars for graphitization studies, 5/8 in, in diameter and 9 in. long, fed through two enlarged sections equidistant from the middle and ends of the bars. Risers of suitable size insured sound castings. Tensile tests were made on the castings after commercial mallealleizing and after special heat treatments to be described. The analyses of the white irons are given in Table 1.

Jan 1, 1935

By W. B. HILLHOUSE

AN excerpt from the Alabama State Mining Law, pertaining to, transporting men' into and out of the mines, reads as follows: "A trip of empty cars may be operated for the purpose of taking employees into and out of the mine, where the distance to and from their work exceeds one mile." The State Mining Department of Alabama includes in its inspection the transportation of men into and out of the mines, also studying and noting improvements, or progress made, that would tend to create a greater assurance of safety in this practice. Everyone is familiar with the original safety methods employed in man-trip transportation, such as passing a rope around the trip of cars, or through the cars, fastened in the conventional manner, and with the usual "clog," commonly called a drag, on the rear end. Also there is a more advanced method of transporting men, such as the double-rope system, which is feasible on slopes used exclusively for this purpose, and is very satisfactory. However, for the past eighteen months; the Republic Steel Corp. and the Tennessee Coal, Iron & Railroad Co. have adopted a practice that shows

Jan 1, 1935

By C. A. Wright

The average lead and zinc content of the ores mined and milled in the Joplin district is low as compared with that of other lead and zinc deposits throughout the United States. Because of this fact and of the high grade of the concentrates, the ratio of concentration is unusually high. Most of the operating companies have aimed to produce as high a grade of concentrate as possible in order to obtain the highest price for their product. They have done this at the sacrifice of the percentage of zinc recovered. The average percentage of zinc recovery is from 60 to 70 per cent. For percentage of recoveries from actual mill tests, see tables. The concentration is commonly effected by crushing the ore to ½-in. (12.7 mm.) size and subjecting it to a roughing and cleaning over two or more large Cooley jigs, of the Harz type, the finer sands being treated on the usual types of sand and slime tables. The treatment of slimes by flotation is being tested at several of the larger mills. Coarse Concentration When the ore has been hoisted from the mine it is dumped onto a chute leading to a grizzly made of iron bars, usually heavy rails, spaced 4 to 5 in. (101 to 127 mm.) apart. The oversize is caught on the grizzly, the mineralized pieces are broken with sledge hammers so as to pass through, and the boulders that are practically barren are sorted out by hand and trammed to the waste-rock pile. The proportion of waste rock thus sorted out varies from a fraction of 1 per cent. to 15 per cent., depending on the nature of the rock. Crushing The undersize material, 5 in. (127 mm.) or less in diameter, passes through the openings of the grizzly into the mill hopper below. From

Jan 1, 1918

By Cyril Stanley Smith

For many years sulphur and its congeners selenium and tellurium have been regarded as very harmful elements in copper and copper-rich alloys. Like many similar prejudices, this has been found to be partly wrong. All three of these elements actually have no great effect on the working properties of copper and its alloys, and are desirable additions in that they considerably enhance the machinability of alloys in which they are present. Because of their possible commercial importance, a study of the machinability and other properties of the pure binary alloys was made, as described in this paper, and the effect of selenium on a large number of copper alloys was determined. The current opinion regarding the deleterious effects of elements in this group undoubtedly arose because of occasional failures of tough-pitch copper containing unusually high tellurium, and because of the well-known fact that sulphur causes spewing and unsoundness in tough-pitch copper. Siebe,1 also Deretchey and Margolina,2 studied the effect of sulphur on copper and showed that in the absence of oxygen it was present in the form of copper sulphide, which was less harmful to the properties than an equivalent amount of copper oxide. No data have been published on selenium and tellurium, although the statement is often made, following Eggleston,3 that tellurium makes copper hot-short. Copper specifications call for only traces of these elements. Skowronski and Mosher4 give data on the effect of selenium and tellurium on the conductivity of tough-pitch copper. In private communication Mr. Skowronski says that the samples were hot-forged from small castings and drawn to 0.081 in. diameter, but it should not be inferred from this that these elements are harmless to the working properties of wirebars and commercial shapes. Constitution and Microstructure Constitution.—Sulphur, selenium and tellurium exist in their alloys with copper in the form of copper sulphide, selenide or telluride. These compounds are practically insoluble in the solid state and possess limited

Jan 1, 1938

By Leslie F. Tedsen, John E. Dorn, Alan E. Flanigan

It is necessary occasionally to use aluminum-alloy sheet where moderately elevated temperatures are encountered. Considerable attention has been directed toward determining the influence of "artificial aging" on the room-temperature properties of the precipitation-hardenable alloys, as testified by numerous company reports and by references I to 4. Investigations on the properties at elevated temperatures are few, however, and have not always covered the range of times and temperatures of greatest interest. The present investigation was instituted to overcome this deficiency. The work was done for the Office of Production Research and Development of the War Production Board, under the supervision of the War Metallurgy Committee, as a part of the "restricted" Project NRC-548. It has been released for publication by the Office of Production Research and Development. AS is well known, the high-strength aluminum alloys achieve their remarkable properties as a result of precipitation-hardening. In production they are subjected to a solution heat-treatment followed by quenching, to retain the supersaturated solid solution. The solution treatment is followed by "aging" (precipitation-hard- ening) either at room temperature or at a suitable elevated temperature. A considerable increase in tensile and compressive yield stresses results from precipitation at room temperature ("natural aging"). Through the elevated-temperature process ("artificial aging") it is possible to obtain values of yield stress considerably higher than those attainable by natural aging. The increase in yield stress is accompanied by a smaller gain in ultimate tensile stress and by a decrease in elongation. During the first stages of artificial aging the yield stress increases steadily until it reaches a maximum value. In this condition the material is said to be "fully aged." Further exposure results in "averaging," attended by a steady decrease in yield stress. In the production of the artificially aged materials, temperatures and times are selected to achieve full aging. The following important characteristics are associated with the process: 1. The higher the temperature, the more rapidly is the fully aged condition attained. :7

Jan 1, 1946

By Cyril Stanley Smith

For many years sulphur and its congeners selenium and tellurium have been regarded as very harmful elements in copper and copper-rich alloys. Like many similar prejudices, this has been found to be partly wrong. All three of these elements actually have no great effect on the working properties of copper and its alloys, and are desirable additions in that they considerably enhance the machinability of alloys in which they are present. Because of their possible commercial importance, a study of the machinability and other properties of the pure binary alloys was made, as described in this paper, and the effect of selenium on a large number of copper alloys was determined. The current opinion regarding the deleterious effects of elements in this group undoubtedly arose because of occasional failures of tough-pitch copper containing unusually high tellurium, and because of the well-known fact that sulphur causes spewing and unsoundness in tough-pitch copper. Siebe,1 also Deretchey and Margolina,2 studied the effect of sulphur on copper and showed that in the absence of oxygen it was present in the form of copper sulphide, which was less harmful to the properties than an equivalent amount of copper oxide. No data have been published on selenium and tellurium, although the statement is often made, following Eggleston,3 that tellurium makes copper hot-short. Copper specifications call for only traces of these elements. Skowronski and Mosher4 give data on the effect of selenium and tellurium on the conductivity of tough-pitch copper. In private communication Mr. Skowronski says that the samples were hot-forged from small castings and drawn to 0.081 in. diameter, but it should not be inferred from this that these elements are harmless to the working properties of wirebars and commercial shapes. Constitution and Microstructure Constitution.—Sulphur, selenium and tellurium exist in their alloys with copper in the form of copper sulphide, selenide or telluride. These compounds are practically insoluble in the solid state and possess limited

Jan 1, 1938

By E. P. Jennings

Large deposits of titaniferous iron-ore occur at Caribou, an old silver-mining camp in Boulder county, Colo., 17 miles west by south of Boulder, and a few miles northwest of the tungsten-mines. Professor Regis Chauvenet1 published a part analysis of the ore many years ago, but gave no description of the wall-rock. Caribou hill, which contains both the silver-bearing veins and the iron-ore deposits, is a low dome of gabbro surrounded by the Archæan schists and gneisses of the Front range of the Rocky mountains, the peaks of which, a few miles west of Caribou, attain an elevation exceeding 12,000 ft. The gabbro stock is roughly elliptical in outline, with approximate diameters of 1 and 3 miles. The crest of the dome is 10,500 ft. above sea-level, and the town and ore-cleposits are 500 ft. lower. Outcrops of the iron-ore occur in the town and extend NW. for 2,000 ft., where they disappear under the swampy meadows of Caribou park. Portions of the deposit are covered by drift, but one continuous outcrop is 900 ft. long and from 200 to 250 ft. wide. A second deposit is 0.25 mile south of the town along the eastern slope of the hill. It is not as well defined as the north bed, but is approximately 1,000 ft. long and from 100 to 200 ft. wide. The easily disintegrated ore does not form prominent outcrops, but the outlines of the deposits are readily traced by the large amount of ore fragments that cover the ground. Trenches and pits sunk on the outcrop expose a roughly banded magnetic iron-ore, with pyroxene as the principal gangue-mineral. The Gabbro. This rock was classified in the field as a gabbro from the presence of pyroxene and striated feldspars, and for convenience the field-name will be retained.

Jan 1, 1913

By Leslie F. Tedsen, Alan E. Flanigan, John E. Dorn

It is necessary occasionally to use aluminum-alloy sheet where moderately elevated temperatures are encountered. Considerable attention has been directed toward determining the influence of "artificial aging" on the room-temperature properties of the precipitation-hardenable alloys, as testified by numerous company reports and by references I to 4. Investigations on the properties at elevated temperatures are few, however, and have not always covered the range of times and temperatures of greatest interest. The present investigation was instituted to overcome this deficiency. The work was done for the Office of Production Research and Development of the War Production Board, under the supervision of the War Metallurgy Committee, as a part of the "restricted" Project NRC-548. It has been released for publication by the Office of Production Research and Development. AS is well known, the high-strength aluminum alloys achieve their remarkable properties as a result of precipitation-hardening. In production they are subjected to a solution heat-treatment followed by quenching, to retain the supersaturated solid solution. The solution treatment is followed by "aging" (precipitation-hard- ening) either at room temperature or at a suitable elevated temperature. A considerable increase in tensile and compressive yield stresses results from precipitation at room temperature ("natural aging"). Through the elevated-temperature process ("artificial aging") it is possible to obtain values of yield stress considerably higher than those attainable by natural aging. The increase in yield stress is accompanied by a smaller gain in ultimate tensile stress and by a decrease in elongation. During the first stages of artificial aging the yield stress increases steadily until it reaches a maximum value. In this condition the material is said to be "fully aged." Further exposure results in "averaging," attended by a steady decrease in yield stress. In the production of the artificially aged materials, temperatures and times are selected to achieve full aging. The following important characteristics are associated with the process: 1. The higher the temperature, the more rapidly is the fully aged condition attained. :7

Jan 1, 1946

By C. C. Wright, T. S. Spicer, R. G. Bowman

In recent years considerable publicity has been given to the problem of atmospheric pollution by fuel-burning equipment. Legislation has been stimulated and smoke ordinances have been enacted, the provisions of which show a definite trend toward stricter control of the emissions not only from the stacks of industrial fuel users but also from the chimneys of domestic consumers. As a result of war conditions, some slackening in the enforcement of these ordinances may be noted, but this is only a temporary expediency caused by the changes necessary in the distribution of the nation's fuel supplies and difficulties in securing the necessary equipment. Previous trends may be expected to continue in the postwar period. Largely because of the consumer demand for automatic heat, but partly because of the legislation against smoke emission, there has been a marked increase in the use of domestic underfeed stokers with the past decade. When correctly adjusted and operated, these units reduce the smoke emission materially, so that even the high-volatile bituminous coals may be burned with little or no emission of objectionable smoke. Unfortunately, however, the use of the domestic underfeed stoker introduces another problem; namely, fly-ash. Production of Fly-ash The term "fly-ash" is a misnomer, since the fly material is generally a mixture of small carbonaceous particles varying from green coal to coke, and inorganic particles ranging from fluffy ash to small particles of fused clinker. For want of a more comprehensive name, however, the term fly-ash is used throughout this paper to include all the fly material. Even with hand-fired furnaces a certain amount of fly-ash is produced, which necessitates periodic cleaning of the boiler flues or furnace radiator, the smoke pipe, and occasionally the chimney itself. With stoker operations the amount of fly-ash is increased many fold, because of the higher velocity of air travel through the fuel bed. Frequently the amount of this fly-ash attains such proportions as to constitute a definite nuisance to the householder and his neighbors and distracts very materially from the otherwise automatic or semi-automatic performance of the stoker. Virtually all the boilers and hot-air

Jan 1, 1944

By T. S. Spicer, C. C. Wright, R. G. Bowman

In recent years considerable publicity has been given to the problem of atmospheric pollution by fuel-burning equipment. Legislation has been stimulated and smoke ordinances have been enacted, the provisions of which show a definite trend toward stricter control of the emissions not only from the stacks of industrial fuel users but also from the chimneys of domestic consumers. As a result of war conditions, some slackening in the enforcement of these ordinances may be noted, but this is only a temporary expediency caused by the changes necessary in the distribution of the nation's fuel supplies and difficulties in securing the necessary equipment. Previous trends may be expected to continue in the postwar period. Largely because of the consumer demand for automatic heat, but partly because of the legislation against smoke emission, there has been a marked increase in the use of domestic underfeed stokers with the past decade. When correctly adjusted and operated, these units reduce the smoke emission materially, so that even the high-volatile bituminous coals may be burned with little or no emission of objectionable smoke. Unfortunately, however, the use of the domestic underfeed stoker introduces another problem; namely, fly-ash. Production of Fly-ash The term "fly-ash" is a misnomer, since the fly material is generally a mixture of small carbonaceous particles varying from green coal to coke, and inorganic particles ranging from fluffy ash to small particles of fused clinker. For want of a more comprehensive name, however, the term fly-ash is used throughout this paper to include all the fly material. Even with hand-fired furnaces a certain amount of fly-ash is produced, which necessitates periodic cleaning of the boiler flues or furnace radiator, the smoke pipe, and occasionally the chimney itself. With stoker operations the amount of fly-ash is increased many fold, because of the higher velocity of air travel through the fuel bed. Frequently the amount of this fly-ash attains such proportions as to constitute a definite nuisance to the householder and his neighbors and distracts very materially from the otherwise automatic or semi-automatic performance of the stoker. Virtually all the boilers and hot-air

Jan 1, 1944

By R. M. (Mike) Robb

Introduction The requirements to investigate a wide range of alternatives and analyze a variety of ‘what if’ questions make the automation of pit design a requirement in today’s rapidly changing mining industry. The wide-spread application of computers has relieved the engineer of much of the tedious and error-prone work related to mine design. He is thus free to do the creative and innovative thinking for which he is trained. It is now possible to investigate a large number of alternative pit designs in a reasonably short time period. In the past it was very easy for a team of engineers to consume 12 to 14 man-months in the detailed hand design of a large open pit. The pressure of today's mining industry, the desire to investigate a variety of alternative designs, and the shortage of qualified engineers make the slowness of hand design less preferred.

Jan 1, 1979

By F. H. Kihlstedt

The Larap iron deposits, 125 miles east of Manila, are the biggest high-grade iron deposits in the Philippines, and have in seven years produced nearly 4 million tons of 60 per cent ore. Magnetic surveying followed by churn and diamond drilling cheaply developed a score of million tons. The ore zone is a wedge of metamorphic rocks in fresh, Miocene sediments overlain by agglomerates, which seem to have filled a river valley eroded in the sediments. A mild overthrust of the competent agglomerates crumbled the shale in front. Solutions gradually turned it into more competent hornfels and deposited pyrite, then magnetite and pyrite in the pores. As the temperature rose large bodies of magnetite with some pyrite were deposited by replacement and in open cavities in tensional areas of overthrust shears. At still higher temperature magnetite and calcium-magnesium silicates formed other bodies in similar cavities, and finally the thrust zone was invaded by syenite porphyry, causing high-temperature alteration products. Possibly, as temperature abated, more high-grade ore was deposited. The complicated faulting indicates dynamic, chronological and spatial changes of mineralization rather than zoning in a static system. Noncommercial copper, molybdenum and some gold accompanied the iron mineralization. In the thirties the Philippines gained a justified reputation as a country of considerable mineral wealth. Traces of Chinese workings show that these earliest travelers and traders had in a small way exploited the latent gold resources in the Islands. The Spaniards continued this for centuries, but did not succeed in establishing any steady mining industry. Modern technology was required to get it started. The rapid development in the last decade before the war got its impetus from several financial factors, the return to sugar growers of previously collected taxes, the influx of Spanish capital during the civil war in Spain, the influx of Chinese capital when the Japanese started their "China incident," and others. Directly or indirectly much of this capital reached the mining industry; in particular, gold mining. Out of the turmoil of an exceptional mining boom emerged a sufficient number of good and well managed gold properties to send the production to a level above that of any single state in the United States at the time. Other ore deposits besides those of gold also received their share, and for a country without any heavy industries at

Jan 1, 1949

By F. H. Kihlstedt

The Larap iron deposits, 125 miles east of Manila, are the biggest high-grade iron deposits in the Philippines, and have in seven years produced nearly 4 million tons of 60 per cent ore. Magnetic surveying followed by churn and diamond drilling cheaply developed a score of million tons. The ore zone is a wedge of metamorphic rocks in fresh, Miocene sediments overlain by agglomerates, which seem to have filled a river valley eroded in the sediments. A mild overthrust of the competent agglomerates crumbled the shale in front. Solutions gradually turned it into more competent hornfels and deposited pyrite, then magnetite and pyrite in the pores. As the temperature rose large bodies of magnetite with some pyrite were deposited by replacement and in open cavities in tensional areas of overthrust shears. At still higher temperature magnetite and calcium-magnesium silicates formed other bodies in similar cavities, and finally the thrust zone was invaded by syenite porphyry, causing high-temperature alteration products. Possibly, as temperature abated, more high-grade ore was deposited. The complicated faulting indicates dynamic, chronological and spatial changes of mineralization rather than zoning in a static system. Noncommercial copper, molybdenum and some gold accompanied the iron mineralization. In the thirties the Philippines gained a justified reputation as a country of considerable mineral wealth. Traces of Chinese workings show that these earliest travelers and traders had in a small way exploited the latent gold resources in the Islands. The Spaniards continued this for centuries, but did not succeed in establishing any steady mining industry. Modern technology was required to get it started. The rapid development in the last decade before the war got its impetus from several financial factors, the return to sugar growers of previously collected taxes, the influx of Spanish capital during the civil war in Spain, the influx of Chinese capital when the Japanese started their "China incident," and others. Directly or indirectly much of this capital reached the mining industry; in particular, gold mining. Out of the turmoil of an exceptional mining boom emerged a sufficient number of good and well managed gold properties to send the production to a level above that of any single state in the United States at the time. Other ore deposits besides those of gold also received their share, and for a country without any heavy industries at

Jan 1, 1949

By Cyril Stanley Smith, Earl W. Palmer

STRIP of any of the metals used for deep drawing operations occasionally yields cups that are defective because of a rim that varies in height around the cup in a wave-like manner Some such defects are traceable to tools or other press factors, but when the protuberances formed (usually four in number on brass and other copper alloys) are symmetrically disposed with respect to the rolling direction of the strip, they are invariably attributable to the metal The effect is known as "caring" and the protuberances are called "ears" Other terms frequently heard are "tips," "scallops," and "corners " It is recognized that the effect is most commonly a result of a directional crystal structure produced by rolling and annealing operations in the manufacture of the metal strip Numerous papers dealing with various aspects of the caring effect have appeared in the literature, those listed in the references' being especially interesting and valuable An investigation of the factors influencing caring of brass cups has been in progress in the laboratories of the American Brass Co for several years, and it was thought desirable to make some of the results generally available in summarized form The present paper discusses many factors that do and do not contribute to ear formation In addition, a section is devoted to methods of minimizing the caring tendency of brass sheet by proper selection of the cold-rolling and annealing schedule by which it is produced In the space available, it is impossible to quote detailed experimental procedures and numerical results However, the authors make no statement that they do not believe to be properly substantiated, either by experimental evidence obtained under laboratory conditions or by experience in the actual production of deep-drawing brass in the brass mill MECHANISM OF EAR FORMATION It must be clearly understood that the formation on cups of symmetrical ears, four or more in number, is attributable solely to the strip metal, and results from the strip having different deformation characteristics in different directions The tools used in the drawing process, or the type and completeness of lubrication of the strip, have nothing to do with the problem of ears, although they do, of course, greatly affect the "drawing quality" of the strip and the general appearance of the cup A single tip may be drawn up on the rim of a cup because of misalignment of the tools, or because the gauge of metal varies from side to side of the strip The two-ear form that sometimes appears is also traceable to gauge variations However, the four-ear and six-ear symmetrical forms that we are concerned with here are caused by factors inherent in the structure of the metal itself

Jan 1, 1942

By J. R. Mihalisin

Phase changes in as-cast alloys in the Ni2 CoCr-Ni, Ti-NSAl system containing 0.1 wt pct C were studied after heat treatment at 1650°F. It was found that a vegion of CrCo-type s was developed in this system after I1000 hr. The tendency for s formation was dePendent upon the aluminum and litanium content, the s -forming tendency generally becoming more pro-nounced as the latter two elements are increased. s lended to form in interdendritic regioues and was associated with solutioning- of- carbide phases. Electron- vacancy computations for prediction of s formation on these alloys mere in sufficient agreement with what was observed experimentally to indicate that the method should be of value in assessing a-forming potential in cast alloys. However, the correlation of electrotz- vacancy numbers may not be as favorable in cast as cormpared to wrought alloys. THE increasing use of high-temperature alloys for longer times at higher temperatures has resulted in a real need for obtaining information on the phase changes taking place in these alloys since these changes often have a direct effect on properties. This paper reports on a study of the phase changes in Ni-Cr-Co-Al-Ti alloys after prolonged heating at 1650°F. The alloys were selected from the pseudo-ternary system Ni2CoCr-Ni3Ti-Ni3Al and this system was chosen because it is the basis of many of the newer cast commercial superalloys. The attempt here was not to define accurately the boundaries of s formation in the NizCoCr-Ni3Ti-Ni3Al system but to delineate the phase transformations taking place upon heating alloys covering a wide range of chemistries in this system. An addition of carbon was made to all alloys to further simulate commercial alloys. It was hoped that the information generated in this manner would be of more direct use to superalloy designers than an equilibrium diagram approach since commercial alloys generally have outlived their usefulness when equilibrium is attained. EXPERIMENTAL PROCEDURE The alloys were vacuum-melted from carbonyl-nickel pellet, vacuum-grade chromium, electrolytic cobalt, high-purity aluminum and titanium, and spec-trographic-grade carbon.

Jan 1, 1968

By R. W. Powers, M. V. Doyle

ThE solution of a diatomic gas such as 0, or N2 in a metal usually follows Sieverts' law; i. e., Here C is the solute concentration at equilibrium and P, the gas pressure. The proportionality constant Ks is also the equilibrium constant for the reaction 1/2 02 (at pressure, P) - 0 (in solution at [21 concentration., C). to use oxygen as an illustrative gas. Sieverts' law is therefore interpreted to indicate that diatomic gases go into metallic solution atomically and that the solute "gas" atoms interact negligibly with each other. Of course, this interpretation is strictly valid only over the temperature interval in which the reaction indicated in [Z] can be investigated. At temperatures several hundreds of degrees below this interval, the possibility of interactions between solute atoms is conceivable. Indeed, from internal-friction measurements some evidence for the existence of groupings of oxygen atoms in tantalum solid solutions was presented a few years ago.1,2 Over a range of solute concentration, the experimental oxygen internal-friction peak in tantalum, measured as a function of temperature at constant frequency of vibration, can be described as the sum of two elemental peaks, each corresponding to a separate relaxation process. At 0.7 cps, the height of the elemental peak found at 137°C is proportional to the oxygen content, whereas the height of the one at 162°C varies as the square of the oxygen concentration. The 137°C peak was presumed to arise from the stress-induced ordering of oxygen atoms among various classes of octahedral sites in the manner proposed by Snoek.3 The 162°C peak was attributed to a somewhat similar stress-induced ordering process, in which each oxygen atom was interacting with a neighboring oxygen atom. Similarly, the experimental peak due to nitrogen in tantalum can also be described as the sum of two peaks. The height of one varies as the nitrogen concentration and the other as the square of this quantity. In fact, some evidence of solute interactions exist for all oxygen and nitrogen solid solutions of Group V transition metals. However, the interaction energy was not obtained previously for any alloy. The determination of this quantity, as a part of a more intensive study of the interaction between oxygen atoms in solid solution in tantalum, is reported in this paper. PRINCIPLE OF THE EXPERIMENT Consider an equilibrium in a solid solution of tantalum between oxygen atoms which are bound together pairwise and those solute oxygen atoms which are not so associated. 20 (Ta) - O2 (Ta) [3]

Jan 1, 1960

By F. J. Plecity, J. T. Michalak, W. C. Leslie

Isothermal recrystallization and grain growth in zone- and vacuum-melted irons and Fe-Mn alloys, up to 0.60 pct Mn, were studied in the range 480° to 650° C, after 60 pct cold reduction. In initial stages, rate of grain growth and rate of recrystallization of iron decrease with time. The recrystallization is typical of a growth-controlled process, and rate of growth is determined by the extent of recovery. Mn decreases rates of growth and of recrystallizatzon. The recrystallization process changes at about 0.30 pct Mn and nucleation may become time-depetzdet~t. In recent years, considerable effort has been expended in determining the effects of solute elements on recrystallization and boundary migration in fcc metals. The results have indicated that the effects produced by single solute additions are dependent upon both the element added and its concentration.'-' In contrast, there have been very few attempts to determine the characteristics of recrystallization and boundary migration in high-purity bcc metals, especially after heavy deformation, and the effects thereon of single solute elements.9-11 This study was undertaken to determine the recrystallization characteristics of various "high-purity" irons and the effects of manganese additions at two levels of base purity. It was hoped that the information obtained would improve our understanding of the recrystallization of pure metals and aid in formulating a theory for the effect of solute elements. The interest was not entirely academic, for the annealing of low-carbon steels, which is of very great commercial importance, is but poorly understood. MATERIALS The compositions of the irons and iron-manganese alloys used are listed in Table I. The zone-melted iron and Fe-Mn alloys were made by Battelle Memorial Institute. Iron S-1 was arc-melted in a water-cooled steel mold in an argon atmosphere. The ingot was forged into a bar, then given two horizontal zone-refining passes in an alumina boat. Iron V-4 was treated in a similar manner, but was not zone-refined. The iron for the zone-melted Fe-Mn alloys was induction melted in vacuum in MgO crucibles and cast into alumina molds. The ingots were forged into bars, machined to shape, and a groove milled down one side of each. The best available electrolytic Mn was placed in the grooves, and the bars were zone melted. The vacuum-melted Fe-Mn alloys were induction melted in this Laboratory in MgO crucibles and poured into cast-iron molds. Iron V-5 was purchased from National Research Corp. in the form of a small vacuum-cast ingot. The low-carbon steel was made by induction melting in air at the U.S. Steel Corp. Applied Research Laboratory. The history of the materials prior to the final cold reduction differed; these details are given in the Appendix. The penultimate grain size of the principal materials was kept in the range ASTM 2 to 4, except for the low-carbon steel. PROCEDURES The cold work prior to the final recrystallization anneal was kept constant at 60 pct. It is known that rolling procedure can influence the kinetics of recrystallization of ironI2; therefore, all specimens were rolled in one direction only, between clean,

Jan 1, 1962