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By W. A. Backofen, D. Lee, F. S. Jabara

THE empirical character of plasticity analysis insures a continuing need for measurements of the yield surfaces of anisotropic materials. Recently, Wheeler and Ireland (W-I) proposed that an octahedral yield locus could be constructed on the basis of six Knoop hardness indentations. Such simplicity would have obvious appeal, if it led to consistently dependable results. In other recent work, a much more straightforward (and more tedious) method of measurement was used to establish all quadrants of the plane-stress yield loci for two substantially anisotropic titanium alloys.2,3 The same materials have since been reex-amined by the W-I method with results being reported here. A full description of the stress state under a Knoop indentor would be complex. In principle, however, this can be avoided in relating the hardness number to a plane-stress yield locus, by the expedient of superimposing the appropriate hydrostatic component on that state of stress. Six possible orientations of in-dentor on orthogonal (symmetry) planes, along (principal) coordinate directions, are illustrated in Fig. 1(0). Pictured in Fig. l(b) are normal-stress components nominally associated with indentation n: o2(H), directly proportional to the Khn in this case, together with By overlaying a hydrostatic tension, ah, that in general is equal to the stress state around the indentation is reduced to one of plane stress in the x-y plane for which the stress ratio is a The key step in the W-I yield-locus construction is to represent the Khn for any indentor orientation as a vector quantity on the octahedral plane. In the plotting, the vector is given as deviatoric stress components along the principal axes in the ratio , where represents the direction of the minor (width) diagonal and 1 that of the major (length) diagonal. There is no attempt by W-I to justify the 7/1, although it might be supposed that the value originates in the usual ratio of major to minor diagonals in a Knoop indentation of about 7/1. If that were its origin, the link to the deviatoric stress ratio would presumably be made by first taking 7/1 and then turning to the Levy-Mises equation for isotropic material: Interpreted in this way, the W-1 approach seems arbitrary and even contradictory. Yet it would still be favored by two circumstances: the deformation under a Knoop indentor approaches plane strain: when dcw/del =a; and the shape of the locus where plane strain is represented is not overly sensitive either to the exact value of dc,/dcl or to the degree of anisotropy, within a rather wide range of both variables. The second point is illustrated below, after a few additional comments on applying hardness

Jan 1, 1968

By Donald L. Colwell

THIS is a metallurgical war. More than ever before, the mechanized forces and the air-borne warfare are deciding campaigns. Both of these are primarily dependent upon metals. There are two ways of increasing the effective supply of these metals when the demand is greater than the total over-all supply. The American custom, when a shortage of anything develops, is to get more. In the case of some nonferrous metals this has been done. For example, our potential peak output of magnesium will be almost one hundred times the prewar production. Output of aluminun has also been tremendously increased, and production of other metals is being stimulated by every possible means. Our enemies, however, have another successful method of increasing the effective supply of a material, and that is, to eliminate entirely all nonessential uses, and also to use, in essential applications, alternate materials wherever possible. Sometimes, ersatz material is inferior to the original, and consequently does not do the job as well. Often, however, it has been found superior, and many substitute items are now being used both by industry and by the military which will continue even when the original material again becomes available.

Jan 1, 1943

By R. S. Dean

REQUIREMENTS for war materials have led to large scale experimentation upon metallurgical innovations. It is of interest to inquire what this may contribute of permanent value to our existing technology, as innovations adopted during war are apt to be discarded promptly at its end. This is because utilization of substandard ores usually requires a new technology for ore treatment, and a new use-pattern for employment of the products. Thus two very different problems are involved: first, devising a process; then, adopting its products by industry, with readjustments of the use-pattern if necessary. A new process may be as good or better than an old one, but the readjustments required for use of its products may prevent its general adoption if this implies scrapping existing plants and investing much additional capital. Metallurgical innovations are of three kinds: I. The use of substandard material in processes already established; 2. The grading-up of substandard material to render it more suitable for established processes; 3. The adjustment of technology and use-pattern to the raw materials that we have.

Jan 1, 1945

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Nov. 10 to Dec. 10, 1915: F. Lynwood Garrison, Philadelphia, Pa. E. Fleming l'engle, Costa Rico, C. A. William J. Lakeland, Burma, India. Fred Maccoy, El Oro, Mexico. Dwight E. Woodbridge, Duluth, Minn. 0. N. Scott, Toronto, Ont., Canada. Chester A. Fulton, Yonkers, N. Y. K. P. Swenson, Tokyo, Japan. Willet G. Miller, Toronto, Canada. - H. L. Mead, New York, N. Y. L. G. Huntley, Pittsburgh, Pa. E. DeGolyer, Norman, Okla. L. E. Howard, Lockport, N. Y. J. S. Lane, New York, N. Y. H. W. DuBois, Philadelphia, Pa. T. V. Nonactre, Argentina. Howard R. Stewart, London, England. N. H. Darton, of the U. S. Geological Survey, has returned to Washington after a long season of field work in New Mexico investigating the prospects of finding potash deposits in the Red beds.

Jan 1, 1916

By A. Tonejc, A. Bonefacic

As can be seen from the phase diagram A1-W1 the equilibrium solubility of tungsten in aluminum is practically nil at room temperature. By quenching from the liquid state (50,000°C per sec), Varic, Burov, and Kolesnicenko2 obtained A1-W solid solutions up to 0.15 at. pct W. The quenched alloys were in the form of foils, 0.2 to 0.3 mm thick. Considering the results of Duwez and Willens,3 it is obvious that this thickness, which makes impossible a sufficiently rapid quenching, was the main reason for the relatively low content of tungsten dissolved in aluminum found by varic.2 he present note shows that the metastable solubility of tungsten in aluminum can be appreciably extended in aluminum-rich A1-W alloys. The quenching technique and the procedure employed for the preparation of the alloys have been described previously.475 The resulting quenched flakes varied in thickness from 1 to 20 µm from experiment to experiment. However, the measurements of the lattice parameters were carried out only with flakes thinner than 5 µm. The areas of quenched flakes were between 0.1 and 15 mm2. The quenched flakes were placed into a 0.3-mm glass capillary tube which was then mounted in a 114.6-mm-diam Debye-Scherrer camera. Straumanis asymmetric film position and nickel-filtered CuKa radiation were used. The lattice spacings were computed taking X(CuKa1) = 1.54050A for resolved and ?(CuKa) = 1.54178A for unresolved doublets. All specimens were rotated at room temperature, 26o +2°C. The lattice parameters were estimated from extrapolation against the Nelson-Riley function. It was estimated that the error in the lattice parameter of the measurements on a single film lies within +0.0004A for lower and about +0.001A for higher concentrations of tungsten. The lattice parameters of the metastable solid solutions A1-W are plotted vs the concentration of tungsten in Fig. 1 together with the parameters measured by previous investigators.' Each point of the present measurements represents a determination of the lattice spacing on different quenched flakes, for a given concentration of tungsten. With experimental accuracy, the lattice parameters of the metastable solid solutions fall on the straight line passing through the already known data.' As estimated from the uncertainties in the lattice spacings of the solid solutions, the alloys were homogeneous within 0.1 at. pct W. The solubility of tungsten in aluminum-rich A1-W solid solutions obtained by a very rapid quenching technique is increased to about 0.95 at. pct W. This value is 6 times greater than the amount known up to now. -he lattice parameters of the resultant aluminum solid solutions with higher concentrations of tungsten than 0.95 at. pct W did not remain constant AUGER electron spectroscopy has been used to clarify the role of impurities in the embrittlement of AISI 3340 steel. Analysis of fracture surfaces has shown that the embrittled condition is correlated with appreciable antimony segregation at grain boundaries. The low temperature (400" to 600°C) temper embrittlement of low alloy steels containing various combinations of Cr , Ni , Sb , Mn , P , Sn , and As has been examined extensively for many years. General reviews of the area have been made by McMahon1 in 1968, LOW' in 1959, woodfine3 in 1953, and Holloman4 in 1946. Recent work by Low, Stein, Turkalo, and LaForce5 has done much in separating the alloy and

Jan 1, 1970

By H. L. Marcus, P. W. Palmberg

As can be seen from the phase diagram A1-W1 the equilibrium solubility of tungsten in aluminum is practically nil at room temperature. By quenching from the liquid state (50,000°C per sec), Varic, Burov, and Kolesnicenko2 obtained A1-W solid solutions up to 0.15 at. pct W. The quenched alloys were in the form of foils, 0.2 to 0.3 mm thick. Considering the results of Duwez and Willens,3 it is obvious that this thickness, which makes impossible a sufficiently rapid quenching, was the main reason for the relatively low content of tungsten dissolved in aluminum found by Varic.2 he present note shows that the metastable solubility of tungsten in aluminum can be appreciably extended in aluminum-rich A1-W alloys. The quenching technique and the procedure employed for the preparation of the alloys have been described previously.475 The resulting quenched flakes varied in thickness from 1 to 20 µm from experiment to experiment. However, the measurements of the lattice parameters were carried out only with flakes thinner than 5 µm. The areas of quenched flakes were between 0.1 and 15 mm2. The quenched flakes were placed into a 0.3-mm glass capillary tube which was then mounted in a 114.6-mm-diam Debye-Scherrer camera. Straumanis asymmetric film position and nickel-filtered CuKa radiation were used. The lattice spacings were computed taking X(CuKa1) = 1.54050A for resolved and ?(CuKa) = 1.54178A for unresolved doublets. All specimens were rotated at room temperature, 26" +2°C. The lattice parameters were estimated from extrapolation against the Nelson-Riley function. It was estimated that the error in the lattice parameter of the measurements on a single film lies within +0.0004A for lower and about +0.001A for higher concentrations of tungsten. The lattice parameters of the metastable solid solutions A1-W are plotted vs the concentration of tungsten in Fig. 1 together with the parameters measured by previous investigators.' Each point of the present measurements represents a determination of the lattice spacing on different quenched flakes, for a given concentration of tungsten. With experimental accuracy, the lattice parameters of the metastable solid solutions fall on the straight line passing through the already known data.' As estimated from the uncertainties in the lattice spacings of the solid solutions, the alloys were homogeneous within 0.1 at. pct W. The solubility of tungsten in aluminum-rich A1-W solid solutions obtained by a very rapid quenching technique is increased to about 0.95 at. pct W. This value is 6 times greater than the amount known up to now. -he lattice parameters of the resultant aluminum solid solutions with higher concentrations of tungsten than 0.95 at. pct W did not remain constant AUGER electron spectroscopy has been used to clarify the role of impurities in the embrittlement of AISI 3340 steel. Analysis of fracture surfaces has shown that the embrittled condition is correlated with appreciable antimony segregation at grain boundaries. The low temperature (400" to 600°C) temper embrittlement of low alloy steels containing various combinations of Cr, Ni, Sb, Mn, P, Sn, and As has been examined extensively for many years. General reviews of the area have been made by McMahon1 in 1968, LOW' in 1959, woodfine3 in 1953, and Holloman4 in 1946. Recent work by Low, Stein, Turkalo, and LaForce5 has done much in separating the alloy and

Jan 1, 1970

By M. van Swaay, C. E. Birchenall

Palladium has a large capacity for the dissolution or occlusion of hydrogen; the gas also diffuses very rapidly through the metal. Palladium thimbles are widely used in the laboratory for purification of hydrogen by diffusion. The use of palladium filters could be extended to several large-scale applications if greater stability of the permeation process could be attained. In this paper a number of aspects contributing toward this goal are discussed, and new data on solubility and diffusivity are given. Palladium sheets of 0.005, 0.010, or 0.020 in. thickness were prepared by three procedures: casting and rolling, sintering palladium powder, and sintering palladium powder to which 0.1 pct thorium oxide had been added. Half-inch diam circular specimens were cut and clamped in a stainless steel holder provided with knife edges to seal the palladium sheet with soft copper gaskets. The seals were tested for leaks at l0-5 mm Hg. No difficulties from this source were encountered even after many temperature cycles in the system. The holder was silver-soldered to Kovar-glass seals and attached to the system through glass ball joints. Each joint was sealed with Apiezon wax and was adjacent to a cold trap. In several experiments the holders were fused directly into the system, eliminating the ball joints, to show that the wax did not affect the filter. Three filter holders were supported in holes in a stainless steel cylinder, which also acted as a temperature equalizing block inside the resistance wound furnace. The measuring thermocouple was inserted in one of the holders. A potentiometric controller with control thermocouple on the furnace heater winding maintained ± 0.2oC. Electrolytic hydrogen was purified and stored as shown in the flow diagram, Fig. 1. It could be admitted to either or both sides of the palladium specimens. Only a mechanical pump was used, for even high pumping speeds would not bring the pressure on the off-gas side of the filter below 10 to 50p Hg owing to the rapid hydrogen flow through the filters. A series of steady-state permeability studies allowed identification of several conditions of permeability loss. A constant fore pressure was maintained while the low-pressure face was pumped. After enough time had elapsed for a steady flow to be established the pump was cut off, and the rate of pressure increase in a thermostated bulb was measured to determine the flow rate. The time delay method of Daynes1,9 was adopted since it offered the possibility of determining solubilities and diffusivities. For each measurement both sides of the filter were evacuated for 15 min, which gave about 10-4mm Hg residual pressure. Hydrogen was admitted to one side or the other of the filter at a fixed pressure. The pressure on the off-gas side was observed as a function of time. A

Jan 1, 1961

By A. W. Gauger

IT is with some trepidation that I approach my subject, for I know that I shall at once incur the suspicion of the mechanical engineer, with his concern for boiler tests and efficiencies; of the mining engineer, with his mechanization problems; and of the chemical engineer with his unit processes. Nevertheless, it must be recognized that the technology of fuels, the systematic body of knowledge relating to the production, processing and utilization of mineral fuels, has grown to such proportions and involves so many widely diverse applications of fundamental science and engineering that it behooves us to stop and consider just what its status is in relation to other technologies, as well as in relation to the present and future needs of the social order. The time has come when technologists, applied scientists and engineers must consider the possible effects that their achievements may have 0n Society. The development of a machine to replace several hundred men is a fine achievement when considered solely from the point of view of creative endeavor. But what of the men who are displaced by the machine! Does not the responsibility for the development of this machine embrace as well the consequences of obsolescence and technological unemployment resulting from such development? I believe that it does and that we must recognize this fact in our practice of engineering and technology as well as in the training of future engineers and technologists. MAGNITUDE OF THE FUELS INDUSTRY Fuel technology is the body of knowledge that relates to the mineral fuels. The fuels industry is by far the most important of all our mineral industries. The chart in Fig. I, reprinted from U. S. Bureau of Mines Information Circular No. 6643, indicates the comparative values of metals, fuels and other nonmetallic minerals for the year 1929. Of the grand total of 13 1/4 billions of dollars in value of minerals at the mines, the mineral fuels contributed 48 per cent. Coal, with 34.4 per cent, exceeded the value of any other single mineral. In fact, the value of the production of the Pennsylvania anthracite mines alone annually exceeds the value of the gold production of the entire world. Petroleum and natural gas in 1020 contributed 14.3 per cent and 3.3 per cent, respectively, of the total value of world mineral production. So much for the world picture; let us now look at the situation in the United States. Over the 60-year period 1880 to 1939, $46,409,727,000 of metallic products, S80,788,852,000 of fuels (coal, petroleum, natural gas, natural gasoline) and $27,871,000,000 of nonmetallic minerals other than fuels were produced. The mineral fuels have contributed 52.7 per cent of the entire mineral wealth produced over this period that has seen such tremendous industrial development in our country. As a matter of fact, our present industrial civilization has been made possible through the use of the

Jan 1, 1942

President-Mrs Robert D Coombs, 375 Paramus Road, Paramus, N J First Vice-President-Mrs Howard R Norsworthy, 333 East 53 Street, New York 22, N Y Second Vice-President-Mrs Arthur Notman, Circle Road, Dongan Hills, Staten Island 4, New York Third Viee-President-Mrs David Eugene Park, 30 Sutton Place, New York 22, N Y Fourth Vice-President-Mrs Cony T Brown, 211 East Abeyta Avenue, Socorro, New Mexico Fifth Viee-President-Mrs J A Carpenter, 245 University Terrace, Reno, Nevada Recording Secretary-Mrs W McG Peirce, 7 Lexington Avenue, New York 10, N Y Asst Recording Secretary-Mrs Arnold H Miller, 601 West 115 Street, New York 25, New York Corresponding Secretary-Mrs Theodore Nagel, 76 Remsen Street, Brooklyn 1, New York Treasurer-Mrs Robert W Rowen, 116 East 68 Street, New York 21, N Y Assistant Treasurer-Mrs Samuel H Dolbear, 11 Broadway, New York 4, N Y Assistant Treasurer-Mrs H A Kursell, 12 Murray Hill Road, Scarsdale, New York

Jan 1, 1955

President MRS THORNS E LLOYD 14 Green Hill Road Morristown, N J First Vice-President MRS A B PARSONS 52 Edgewood Road Scarsdale, N Y Second Vice-President MRS H A PROSSER 1001 Park Avenue New York, N Y Third Vice-President MRS HARRY J WOLF 3 Glenwood Avenue Littleneck, N Y Fourth Vice-President MRS MARK LAWRENCE REQUA 140 North Plymouth Blvd Los Angeles, Calif Fifth Vice-President MRS NEWELL G ALFORD 314 South Homewood Avenue Pittsburgh, Pa

Jan 1, 1952

By Arnold Hoffman

A RESPONSIBLE steel executive recently declared that scrap shortages, despite fantastic prices reaching up to $50 per ton, are responsible for the loss of 140,000 tons of steel a month and that in March 1947 alone 25 more steel furnaces could have been operating were it not for scrap scarcities. His answer to this serious situation was to ask for a speedier flow of scrap and also abolition of Government control over pig iron distribution. It would be more logical, perhaps, if an answer to this growing problem of scrap deficiency were sought within the steel industry itself. As long ago as 1933, L. B. Lindemuth, a consulting steel metallurgist, warned the steel industry that a shortage of scrap was inevitable and that beyond 1938, adequate supplies for open-hearth furnaces could not be expected. The outbreak of war, with consequent phenomenal demands on the industry, accelerated production of steel and further worsened the scrap situation. Today we are suffering from a condition which could have been prevented had the industry been more far-seeing and provided for an inevitable contingency. However, better late than never, and measures can now be taken to alleviate permanently scrap shortages in the future. This can be done by greater utilization of heavy sinter which experience proved is an excellent substitute for scrao and lump ore.

Jan 1, 1947

By Walter R. Hibbard, Cyril Stanley Smith

IN 1929 one of the authors1 determined the constitution of copper-silicon-manganese alloys contailling over go per cent copper. Through a combination of circumstances the presence of the copper-silicon kappa phase was overlooked in both binary and ternary systems. In the binary system the omission has already been rectified.2,3 To establish the limits of this phase in the ternary system, the samples that had been heat-treated at the time of the original research have now been re-examined, using more careful technique. Full details of the compositions used and the temperatures and times of heat-treatment are to be found in the earlier paper.2 The etching reagent now used to distinguish the kappa phase had the following composition: hydrogen peroxide (30 vol.), 2o c.c.; water, 25 c.c.; 20 per cent potassium hydroxide solution, 5 c.c.; ammonium hydroxide (0.90 sp. gr.), 50 c.c. 'I'able I lists the newly observed structures. In virtually every case the constituents are the same as those previously recorded, except where kappa is now shown to be present as a result of the improved etching technique. X few other changes will be noted (No. 138 at 450°C., No. 147 at 550°C., Nos. 153 and 149 at 75o°C.). The change from liquid to beta in equilibrium with kappa in No. 137 at 800°C. is based upon newly heat-treated samples. The alloy is very near the solidus at 800°C. and probably there was a slight error in the old heat-treatment temperature. The isothermal phase diagrams shown in Figs. I to 6 were reconstructed on the basis of the new studies. The presence of manganese does not greatly change the composition limits of the kappa phase or cause the K-a + Y change to occur at a markedly different temperature. There is some uncertainty regarding the range of existence of beta, for alloys were not spaced very closely in composition. The proposed diagrams, however, are in accordance with the available experimental data and with the dictates of the phase rule. Theoretically necessary fields with no experimental points are delineated by dotted lines. The alpha boundaries at all temperatures are shown together in Fig. 7. This includes also some additional points on the alpha boundary at 300' and 350°C., which were obtained as a result of electrical-conductivity measurements. Two series of seven alloys with increasing manganese content but with silicon constant at 1.90 + 0.03 per cent or 2.42 ±. 0.05 per cent were cast in ingots of 3-in: diameter. These were hot-rolled, homogenized and drawn to wire, finished at 0.08-in. diameter with a 61 per cent reduction of area following annealing at 700°C. Conductivity determinations were made before and after annealing for 30 days at 300°C. or 21 days at 350°C. Figs. 8 and 9 show the change of conductivity produced by this annealing, plotted against manganese

Jan 1, 1942

By Walter R. Hibbard, Cyril Stanley Smith

IN 1929 one of the authors1 determined the constitution of copper-silicon-manganese alloys contailling over go per cent copper. Through a combination of circumstances the presence of the copper-silicon kappa phase was overlooked in both binary and ternary systems. In the binary system the omission has already been rectified.2,3 To establish the limits of this phase in the ternary system, the samples that had been heat-treated at the time of the original research have now been re-examined, using more careful technique. Full details of the compositions used and the temperatures and times of heat-treatment are to be found in the earlier paper.2 The etching reagent now used to distinguish the kappa phase had the following composition: hydrogen peroxide (30 vol.), 2o c.c.; water, 25 c.c.; 20 per cent potassium hydroxide solution, 5 c.c.; ammonium hydroxide (0.90 sp. gr.), 50 c.c. 'I'able I lists the newly observed structures. In virtually every case the constituents are the same as those previously recorded, except where kappa is now shown to be present as a result of the improved etching technique. X few other changes will be noted (No. 138 at 450°C., No. 147 at 550°C., Nos. 153 and 149 at 75o°C.). The change from liquid to beta in equilibrium with kappa in No. 137 at 800°C. is based upon newly heat-treated samples. The alloy is very near the solidus at 800°C. and probably there was a slight error in the old heat-treatment temperature. The isothermal phase diagrams shown in Figs. I to 6 were reconstructed on the basis of the new studies. The presence of manganese does not greatly change the composition limits of the kappa phase or cause the K-a + Y change to occur at a markedly different temperature. There is some uncertainty regarding the range of existence of beta, for alloys were not spaced very closely in composition. The proposed diagrams, however, are in accordance with the available experimental data and with the dictates of the phase rule. Theoretically necessary fields with no experimental points are delineated by dotted lines. The alpha boundaries at all temperatures are shown together in Fig. 7. This includes also some additional points on the alpha boundary at 300' and 350°C., which were obtained as a result of electrical-conductivity measurements. Two series of seven alloys with increasing manganese content but with silicon constant at 1.90 + 0.03 per cent or 2.42 ±. 0.05 per cent were cast in ingots of 3-in: diameter. These were hot-rolled, homogenized and drawn to wire, finished at 0.08-in. diameter with a 61 per cent reduction of area following annealing at 700°C. Conductivity determinations were made before and after annealing for 30 days at 300°C. or 21 days at 350°C. Figs. 8 and 9 show the change of conductivity produced by this annealing, plotted against manganese

Jan 1, 1942

PRESIDENT HERBERT HOOVER, STANFORD UNIVERSITY; CAL. PAST PRESIDENTS SIDNEY J. JENNINGS NEW YORK, N. Y. HORACE V. WINCHELL MINNEAPOLIS, MINN. FIRST VICE-PRESIDENT EDWIN LUDLOW, NEW YORK, N. Y. TREASURER GEORGE D. BARRON NEW YORK, N. Y.

Jan 1, 1923

By Billy L. Crowder, John M. Fairfield

The implantation of B+ , P+, and As&apos; into silicon has been studied with the purpose of making shallow p-n junctions. The influence of such parameters as 1) ion energy, 2) target orientation and temperature, 3) total dose, and 4) annealing schedule was investigated. An energy range of 70 to 300 kev was used for boron and phosphorus implants and up to 500 kev for arsenic. It is found that the experimental projected range agrees well with theory and that shallow junction depths can be made reproducibly. ION implantation has received much attention recently as a technique for doping semiconductors. Specifically, it has the potential of supplementing or replacing the diffusion process as a method for making p-n junctions. In a few specific cases it has been used successfully to make semiconductor junction devices. Potential advantages of ion implantation doping over diffusion techniques are: 1) It affords greater control of shallow junction depths (< 0.2 µ) while maintaining high peak concentrations. This is particularly important for high-speed switching devices, since lower junction capacitances and resistances can be achieved. 2) More precise registration of small planar structures can be realized if proper masking procedures are employed. This advantage is especially useful in the design of high-density integrated circuits. It has been used to advantage in FET fabrication since the edge of the source or drain can be aligned precisely at the edge of the gate electrode.&apos; 3) Ion implanatation permits lower temperatures than diffusion techniques. This factor alleviates the problem of compatibility of diffusivities often encountered when designing multiple-junction structures. Also, the lower temperatures create fewer thermal defects and dislocations, which may account for the high efficiency of some ion-implanted solar cells.2 4) Impurity profiles can be more easily tailored to resemble ideal distributions. Successful exploitation of the potential advantages of ion implantation techniques will depend on increased knowledge and understanding of the subject. The factors likely to be influential in determining impurity distribution profiles in ion-implanted single-crystal targets have been reviewed by J. F. Gibbons.3 In addition to the mass and energy of the implanted ion, the total dose, target orientation, and target temperature are important parameters. The annealing temperature required for removing lattice damage and incorporating the implanted species on an electrically active site is very important. This paper describes an investigation of some of these factors. Implants of boron, phosphorus, and arsenic into silicon have been studied. Energy ranges of 50 to 300 kev were used for boron and phosphorus and up to 500 kev for arsenic. In addition to the implantation energy, the effects of total dose, target temperature, and post implant anneal have been investigated. EXPERIMENTAL PROCEDURE The implantation targets were silicon wafers cut from Czochralski-grown crystals, lapped, and chemically polished. The orientations were (111), (110). and (100) with misorientations of up to 7 deg from the principal axis. For this study, accurate target alignment (i.e., within 0.1 deg) was not available and quoted misorientation values should be regarded as approximate . The implantation equipment consisted of an ion source, a 300-kev linear accelerator tube, an electromagnetic separator, and the associated target supporting and beam focusing assemblies. The ion source was a simple oscillating electron type source,4 which has been described elsewhere.5 The gaseous compounds BF3, PF5, and AsH3 were used as ion sources for B+, P+, As+, and AS+&apos;. Analyzed current levels of up to 20 pamp could be obtained; however, for this investigation target current levels of 1-3 µ amp were usually employed. The analyzed ion beam was collimated through a double slit (1.4 x 0.4 cm) and swept perpendicularly to the long axis of the slit such that an area of about 2 sq cm on each target was covered. Dosages of around 1015 cm-2 were normally employed, but smaller amounts were also used for comparison. A uniform flux density over the bombarded area was assured by the continuous use of profile monitors similar to those described by Wegner and Feigenbaum.6 Post-implant annealing was accomplished in an argon atmosphere in a temperature range of 600" to 950°C. It was not part of the purpose of this investigation to study the annealing kinetics; however, some isochronal and isothermal anneal experiments were conducted to determine the time and temperature necessary to render a reasonably high portion of the implanted ions electrically active (i.e., higher than 50 pct). Post-implant anneal temperatures of around 900° and 600°C were required for boron, and arsenic and phosphorus implants, respectively. Arsenic and phosphorus implants increased in conductivity rather abruptly at the proper anneal temperature of the isochronal curve, but boron increased more gradually over a wider range. Isothermal anneal curves were reasonably flat after 10 min, so an anneal time of 1/2 hr was used for the experimental results described below. The profiling techniques were: 1) neutron activation analysis, 2) differential sheet resistance,7 and 3) junction staining.8 The differential sheet resistance technique is commonly employed in this type of study. Its principal disadvantage is the uncertainty of the ef-

Jan 1, 1970

"World Mining and Metals Technology" is the title of this year&apos;s SME-AIME Fall Meeting and Exhibit in Denver, Sept. 1-3, where a record number of exhibits are scheduled for display. The international theme is particularly appropriate, for in addition to the annual SME session, the Third MMIJ-AIME Joint Meeting will be held.

Jan 8, 1976

By Saluja, Sunder S.

Man had to learn to break rocks as early as the Stone Age, when they formed his main source of raw material. He started with chipping and over the years has reached a stage where he can employ atomic blasts and break, with one blast, millions of tons of rock. In between these two extremes there have been several stages of development including fire setting, use of the expansion of water on freezing in chipped cracks in cold climates, the use of low or deflagrating explosive black powder in about the 17th century, the use of high explosives with the discovery of nitroglycerine in 1846 by Sobrero, followed by the monumental discoveries of the great Swedish scientist Alfred Nobel in the latter half of the nineteenth century.

Jan 1, 1968

Organization Place Date 1919 Automotive Engineers New York, N. Y. Feb. 4-6 American Institute of Mining Engineers New York, N. Y. Feb. 17-20 New England Association of Gas Engineers Boston, Mass. Feb. 19 American Institute of Electrical Engineers New York, N. Y. Feb. 19-21 National Society for the Study of Education Chicago, Ill. Feb. 25-28 American Railway Engineering Association Chicago, Ill. Mch. 18-20 American Electrochemical Society New York, N. Y. Apr. 3-5.

Jan 2, 1919

By Francis A. Thomson

T HE engineer of today is by his training, by his traditions, and by the service which he must render, irrevocably committed to taking his part in public life along with the members of the older professions of ministry, medicine and law. Nevertheless, in comparison with these: three, so long recognized as the "learned professions-all three of which grew out of the functions of the priesthood-engineering in any modern sense of the word is a youthful profession indeed. So youthful is engineering in its present significance, that it may be said to date from the labors of John Smeaton, the lighthouse builder; of Simon Newcomen and James Watt, the inventors of the steam engine; and of George Stephenson, the inventor of the locomotive; at the dawn of the 19th century. Great works of an engineering character had, it is true, been executed long before this, but practically all of them had been rule-of-thumb enterprises, dependent upon a plethora of slave labor for their accomplishment. For illustration it is said that at Rio Tinto in the days of Hiram, king of Tyre, 40,000 men worked for a year to produce three tons of silver from the rich outcrop ore. Such an operation can scarcely be called an engineering enterprise, however, when we remember that a fourth of this number of men in these same mines, from which the richest ore was long ago extracted, produce at present over 100 tons of copper per day.

Jan 1, 1925

By T. A. Rickard

The dictionary defines &apos;jargon&apos; as "barbarous or debased language". This description does not suffice. Quiller-Couch has said, it is "a kind of writing which, from a superficial likeness, commonly passes for prose in these days, and by lazy folk is commonly written for prose, yet actually is not prose at all ". The two main vices of jargon, he says, are "that it uses circumlocution rather than short straight speech", like the Babu who reported his mother&apos;s death by saying: "Regret to inform you, the hand that rocked the cradle has kicked the bucket ". Its other chief&apos; vice is that "it habitually chooses vague woolly abstract nouns rather than concrete ones", like the newspaper statement; "He was conveyed to his place of residence in an intoxicated condition", instead of saying, "He was carried home drunk ". Jargon is "an infirmity of speech", it is not journalese, but akin to it. "Like respect- ability in Chicago, jargo4 stalks unchecked in our midst" and renders much technical writing ridiculous. It deals in periphrasis instead of going straight to the point, it loves the abstract rather than the concrete, it dabbles in words of sound rather than of meaning. Avoid it, despise it., if you purpose earnestly to write well. "III literature as in life he makes himself felt who not only calls 4 spade a spade but has the pluck to double spades and re-double." * Jargon is rampant in technical publications. Catalogues and other advertisements are conspicuous offenders, but with these the critic is not concerned, except in so far as such &apos;write-

Jan 1, 1931