Open Access. Powered by Scholars. Published by Universities.®

Metallurgy Commons™

Open Access. Powered by Scholars. Published by Universities.®

Materials Science and Engineering Faculty Research & Creative Works

Articles 211 - 240 of 249

Full-Text Articles in Metallurgy

Evaluation Of Zinc Sulfate Electrolytes By Cyclic Voltammetry And Electron Microscopy, Bruce A. Lamping, Thomas J. O'Keefe Dec 1976

Evaluation Of Zinc Sulfate Electrolytes By Cyclic Voltammetry And Electron Microscopy, Bruce A. Lamping, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

A cyclic voltammetric technique has been developed for approximating the quantities of active chemical species present in zinc sulfate electrolytes. The experimental apparatus consisted of a Pyrex "H" cell, an aluminum cathode encased in a Teflon holder, a carbon anode and a mercurous sulfate reference electrode. Voltammograms were obtained using industrial, purified neutral leach solution (Cominco Ltd., Trail, BC) acidified to give a final concentration of 0.77 M Zn++ and 1 M H2SO4. The polarization curves were then evaluated and used as reference standards to compare with results obtained when various organic and inorganic additions were made. The deposit morphologies …


Void-Strengthening In Aluminum And Its Nature, P. G. Manusmare, Hollis P. Leighly Jan 1976

Void-Strengthening In Aluminum And Its Nature, P. G. Manusmare, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

Temperature and strain rate dependence of yield strength were used to analyze the nature of aluminum strengthened by the formation of voids. Aluminum rods 99.999% pure were quenched and heat treated to form voids with an approximate density of 1013-1014 voids/cm3. Voids in selected samples were observed by electron microscopy. The yield strength of the void strengthened samples was measured at various temperatures from 77 to 593 K and at two strain rates, 3.33 x 10-2/s and 1.67 x 10-3/s. Tests at room temperature and at 77 K were made at various strain rates. The similarity of Coulomb's approach to …


The Martensite Transformation, Manfred Wuttig, Tetsuro Suzuki Jan 1976

The Martensite Transformation, Manfred Wuttig, Tetsuro Suzuki

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


The Effect Of Receiver Pressure On The Observed Flow Pattern In The Hydrostatic Extrusion Of Bimetal Rods, Ronald A. Kohser Jan 1976

The Effect Of Receiver Pressure On The Observed Flow Pattern In The Hydrostatic Extrusion Of Bimetal Rods, Ronald A. Kohser

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


On The Effects Of Antimony And Glue On Zinc Electrocrystallization Behaviour, D. J. Robinson, Thomas J. O'Keefe Jan 1976

On The Effects Of Antimony And Glue On Zinc Electrocrystallization Behaviour, D. J. Robinson, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

An investigation has been made to determine the effects that additions of glue and antimony have on the electrowinning of zinc from acid sulphate solutions. In particular, the zinc crystal growth and cathode current efficiencies were studied in an attempt to establish a correlation between morphology and the nature of the additives. Operating conditions of 55 A ft-2* and 35°C were used for most of the experiments with electrolyte concentrations of approximately 55 gl-1 zinc and 150 gl-1 H2SO4. Additional runs were made at 40,75 and 100 Aft-2 at 30,40 and 50°C in order to verify certain trends. Primarily by …


Anion Grain-Boundary Diffusion In Soidum Chloride, K. S. Sabharwal, J. Mimkes, Manfred Wuttig Dec 1975

Anion Grain-Boundary Diffusion In Soidum Chloride, K. S. Sabharwal, J. Mimkes, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

The grain-boundary diffusion of 131I in Harshaw pure and Ca-doped NaCl was investigated in the temperature range between 430 and 560°C. The Arrhenius plot of the grain-boundary diffusivity parameter Dδ displays a marked dip at around 510°C. It is proposed that this dip is due to a phase transformation occurring at the grain boundary, possibly calcium segregation.


Mechanism Of Uai3 To Uai4 Transformation, Ling Ping Lee, Hollis P. Leighly Jan 1975

Mechanism Of Uai3 To Uai4 Transformation, Ling Ping Lee, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

The compound, UA14, which forms during the peritectic reaction (Liquid + UA13 → UAI4), has a long needlelike shape and reveals the characteristic morphology of a fishtail when cut along the long axis. When cut perpendicular to the long axis, it shows an internal core of another phase, which has been identified as a primary aluminum solid solution. Because of the interesting relationship between the crystallographic structures of UA13 and UA14, the peculiar UA14 morphology can be explained on the basis of a proposed mechanism. The mechanism of UA13 to UA14 transformation has been identified as shear and diffusion controlled …


A Microscopy Study Of Lead Sinter, Thomas J. O'Keefe, C. Bennett, E. R. Cole Feb 1974

A Microscopy Study Of Lead Sinter, Thomas J. O'Keefe, C. Bennett, E. R. Cole

Materials Science and Engineering Faculty Research & Creative Works

Samples of up-draft sinters produced at three different Missouri lead smelters were studied, to determine the chemical phases present, as a first step toward a more complete understanding of the lead blast furnace operation. The sinters seemed to be basically similar, and all the results reported are from samples from one smelter (Herculaneum smelter, St. Joe Minerals). Analytical tools used included the electron microprobe and scanning electron microscope with a non-dispersive X-ray spectrometer attachment Major phase that were positively identified are metallic lead, lead sulfide and zinc ferrite. The predominant lead phase was tentatively identified as a lead oxide-silicate compound. …


Film Formation On Anodically Polarized Lead, H. Vaidyanathan, Ram A. Narasagoudar, Thomas J. O'Keefe, William Joseph James, James W. Johnson Jan 1974

Film Formation On Anodically Polarized Lead, H. Vaidyanathan, Ram A. Narasagoudar, Thomas J. O'Keefe, William Joseph James, James W. Johnson

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


Electronic Contribution To The Entropy Of Solution, Manfred Wuttig Jan 1974

Electronic Contribution To The Entropy Of Solution, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


Magnetostrictive Aftereffect In A Dilute 50fe-50ni-C Alloy, Raj Master, Manfred Wuttig Jan 1974

Magnetostrictive Aftereffect In A Dilute 50fe-50ni-C Alloy, Raj Master, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


Dissolution Potentials And Activation Energies Of Insb Single Crystals, Martin E. Straumanis, Lih Da Hu Jan 1972

Dissolution Potentials And Activation Energies Of Insb Single Crystals, Martin E. Straumanis, Lih Da Hu

Materials Science and Engineering Faculty Research & Creative Works

The rest (or corrosion) and dissolution potentials of InSb single crystals in HC1 were determined. There is no potential difference (within error limits) between the inverse {111} faces in pure HC1. A difference of up to 44 mV and more develops as soon as the InSb electrode is anodically dissolved. The potential becomes less noble in the sequence In{111}, {100}, {110}, Sb{111}. The Tafel relationship is observed over three decades of current density. With additions of FeCl3, FeCl2, K3Fe(CN)6, K4Fe(CN)6, H2C4H4O6 to 2N HC1, the anodic potentials of both inverse {111} faces are shifted to more active values; the e'H …


Irradiation Enhanced Decomposition Of A Nickel-Carbon Solid Solution, B. L. Shriver, Manfred Wuttig Jan 1972

Irradiation Enhanced Decomposition Of A Nickel-Carbon Solid Solution, B. L. Shriver, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

This investigation was performed to determine the effects of room temperature neutron irradiation on the distribution of carbon in a nickel-0.3 wt.% carbon alloy. The experiment consisted of comparing the amount of carbon in solid solution and the internal stresses of both unirradiated and irradiated (1013 fn-cm-2 < ΦF < 1018 fn-cm-2) samples following isochronal anneals between 100 and 1200°C by using the magnetic Dis accommodation technique. The results indicate that the amount of carbon remaining in solid solution decreases with increasing neutron dose. At temperatures below 200°C this is due to the trapping of carbon by mobile irradiation-produced defects. Between 200 and 600°C the formation of metastable carbides is enhanced by the presence of irradiation-produced defects. No differences are observed in irradiated and unirradiated samples above 600°C. © 1972.


Activation Volumes Of Carbon Diffusion In Fcc Iron-Nickel Alloys, J. Keiser, Manfred Wuttig Jan 1972

Activation Volumes Of Carbon Diffusion In Fcc Iron-Nickel Alloys, J. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

The Dis accommodation technique was used to determine the activation volume of carbon diffusion, ΔV, in six fcc iron-nickel alloys. Measurements were made at temperatures ranging from 68 to 90 °C and pressures up to 6 kbar on samples having a nickel content between 31 and 63 at.%. A maximum activation volume of 3.9 cm3/mole was found at 34 at.% nickel. The compositional dependence of ΔV is satisfactorily reproduced by a magnetic-energy continuum model in which it is assumed that the activation free energy of diffusion is essentially ferromagnetic in origin. © 1972 The American Physical Society.


Low Temperature Lattice Parameters And Expansion Coefficients Of Ai2au And Lif Gruneisen Constants Of Lif, Martin E. Straumanis, Jayant S. Shah Jan 1972

Low Temperature Lattice Parameters And Expansion Coefficients Of Ai2au And Lif Gruneisen Constants Of Lif, Martin E. Straumanis, Jayant S. Shah

Materials Science and Engineering Faculty Research & Creative Works

There is no difference in the thermal expansion behavior of an intermetallic compound (Al2Au) and of an ionic (LiF), except in the magnitude of the expansion coefficients, which for both compounds upon cooling below 40°K approach zero. The lattice parameters of the two compounds mentioned decrease uniformly and without anomalies with lowering the temperature, approaching a constant value below 40°K. The a–T relationship between 40 and 180° is given in form of equations. A pump working on the Joule‐Thomson principle was used for cooling. The GRÜNEISEN parameter, γ, of LiF between 40 and 180°K is a constant, contrary to theoretical …


Thermal Expansion Behavior Of Silicon At Low Temperatures, Jayant S. Shah, Martin E. Straumanis Jan 1972

Thermal Expansion Behavior Of Silicon At Low Temperatures, Jayant S. Shah, Martin E. Straumanis

Materials Science and Engineering Faculty Research & Creative Works

Lattice parameters, thermal expansion coefficients and Grüneisen parameters of silicon are determined by an X-Ray diffraction method in the temperature range of 180-40 K without the use of liquid gases. Thermal expansion of silicon becomes negative below 120 K which is discussed in terms of its lattice vibrations and crystal structure. © 1972.


Comment On The Nature Of The Disaccommodation In Hcp Co-C Alloys, J. Keiser, Manfred Wuttig Jan 1972

Comment On The Nature Of The Disaccommodation In Hcp Co-C Alloys, J. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis Dec 1971

Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis

Materials Science and Engineering Faculty Research & Creative Works

Lattice parameters, thermal expansion coefficients, and Grüneisen parameters of tungsten are determined by an x-ray method in the temperature range of 180-40 K without the use of liquid gases. Lattice parameters are expressed as a function of temperature. Thermal-expansion coefficients decrease with temperature and show no anomaly in contrast to a hypothesis proposed by Featherston and Neighbours. Grüneisen parameters γ are decreasing with temperature in accordance with the theoretical predictions. © 1971 The American Institute of Physics.


The Anodic Dissolution Reaction Of Insb: Etch Patterns, Electron Number, Anodic Disintegration, And Film Formation, Martin E. Straumanis, Lih Da Hu Jan 1971

The Anodic Dissolution Reaction Of Insb: Etch Patterns, Electron Number, Anodic Disintegration, And Film Formation, Martin E. Straumanis, Lih Da Hu

Materials Science and Engineering Faculty Research & Creative Works

The etching behavior of the inverse {111} planes of undoped, semiconducting, n-type, InSb single crystals was explored. Depending upon the etchant, including anodic dissolution, various etch patterns were obtained on the inverse planes. In general, the etch pits on the In{111} plane were round, and the face was shiny, whereas the face of the inverse plane was dark and rough. The rates of dissolution in the electrolytes used were very low, especially in absence of oxidizers. The components dissolve as In3+ and Sb3 +. At current densities above 40 or 60 mA cm-2 (on Sb{111} or In{111}), growth of a …


A Magnetic Aftereffect In Dilute H.C.P. Co-C Alloys, J. R. Keiser, Manfred Wuttig Jan 1971

A Magnetic Aftereffect In Dilute H.C.P. Co-C Alloys, J. R. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

A magnetic Dis accommodation in dilute h.c.p. Co-C alloys has been observed around 90°C. The thermally activated process giving rise to the Dis accommodation is characterized by an activation energy of 26 kcal mole-1 and an attack frequency on the order of 10+13 sec-1. An application of the selection rules shows that the Dis accommodation cannot be caused by the redistribution of tetrahedral or octahedral interstitials or any nearest neighbor interstitial pairs as long as the defects interact linearly with the internal magnetic field. © 1971.


Stored Energy Of Room Temperature Deformed Copper, G. J. Filatovs, Hollis P. Leighly Jan 1971

Stored Energy Of Room Temperature Deformed Copper, G. J. Filatovs, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


Activation Volumes Of Interstitial Diffusion In Ferromagnetic Metals And Alloys, Manfred Wuttig, J. Keiser Jan 1971

Activation Volumes Of Interstitial Diffusion In Ferromagnetic Metals And Alloys, Manfred Wuttig, J. Keiser

Materials Science and Engineering Faculty Research & Creative Works

The Dis accommodation technique was used to determine the activation volumes of carbon diffusion ΔV of a Fe-1.4 wt% Si alloy, of hcp cobalt, and of nickel at the temperatures of -21, 75, and 110°C, respectively. The obtained values of ΔV are +0.3 ± 0.3 and -0.6 ± 0.9 cm3 mole-1 for the two relaxations observed in hcp cobalt, and 1.2 ± 0.1 cm3 mole-1 for nickel. These results are discussed in terms of a continuum model that interprets the activation energy of diffusion as a sum of the strain and exchange energies. It is found that in ferromagnetic solids …


On The Activation Entropy Of Interstitial Diffusion In B.C.C. Iron, Manfred Wuttig Jan 1971

On The Activation Entropy Of Interstitial Diffusion In B.C.C. Iron, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


Diffusion In Wide Grain Boundaries, J. Mimkes, Manfred Wuttig Dec 1970

Diffusion In Wide Grain Boundaries, J. Mimkes, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

The rigorous solution of the grain-boundary diffusion problem has been approximated by a series expansion method. The calculations show that higher-order terms may be neglected in the bulk adjacent to the grain boundary. Thus, in this region Whipple's and Suzuoka's solutions represent a close approximation to the problem. Inside the grain boundary, however, higher-order approximations have to be taken into account. These approximations gain importance in the case of wide grain boundaries. The solutions obtained for an instantaneous source have been fitted to available grain-boundary diffusion data of Ni2+ in MgO at 1200°C. Numerical calculations give for the bulk diffusion …


Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis Dec 1970

Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


The Fe-Ho Binary System, G. J. Roe, Thomas J. O'Keefe Sep 1970

The Fe-Ho Binary System, G. J. Roe, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

The Fe-Ho phase diagram was determined on the basis of data obtained by X-ray diffraction, metallographic and differential thermal analysis techniques. Since emphasis was centered in the region where intermetallic compounds predominate, neither the iron nor holmium terminal regions were included in this study. Eutectic reactions were found to occur at 16.5 wt pct Fe and 875° C, 61 wt pct Fe and 1284° C, and 79 wt pct Fe and 1338° C. The congruent melting points of the compounds Ho6Fe23 and Ho2Fe17 were found to be 1332° and 1343° C, respectively. Two other intermetallic compounds were found, HoFe2 and …


Exact Solution For A Model Of Dislocation Pipe Diffusion, J. Mimkes, Manfred Wuttig Jan 1970

Exact Solution For A Model Of Dislocation Pipe Diffusion, J. Mimkes, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

The dislocations are treated as an ideal array of parallel pipes of radius and diffusivity Dp embedded in the bulk material of the diffusivity Db. The exact solution of this problem of diffusion along semi-infinite edge dislocations is presented for cubic, tetragonal, and hexagonal crystals. The solution makes it possible to evaluate the dislocation pipe radius a and the ratio of diffusivities from one experiment. It is applied to experimental data for self-diffusion in tellurium available in the literature. The results of the calculations are a dislocation pipe radius a=(1.5 0.5)x10-4 cm and an activation energy for the pipe diffusion …


Cation Grain-Boundary Diffusion In Sodium Chloride, K. R. Riggs, Manfred Wuttig Dec 1969

Cation Grain-Boundary Diffusion In Sodium Chloride, K. R. Riggs, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


Isotope Effect Of Carbon Diffusion In An Fe-Si Alloy, Manfred Wuttig, E. T. Yen Jan 1969

Isotope Effect Of Carbon Diffusion In An Fe-Si Alloy, Manfred Wuttig, E. T. Yen

Materials Science and Engineering Faculty Research & Creative Works

The isotope effect of carbon diffusion in dilute iron silicon alloys containing 28Si and 30Si has been measured below room temperature using the Dis accommodation technique. The time dependence of the reluctivity has been analyzed in terms of two relaxation processes which are due to the reorientation of carbon interstitials in Fe-Fe and Fe-Si sites respectively. The ratio of the relaxation times of the two carbon isotopes 13C and 12C τ13/τ12 is 1.037 for the former and 1.007 for the latter process in the Fe+28Si alloy. The ratios of the relaxation times of the same carbon isotope 12C contained in …


Additional Magnetic Disaccommodations In Ternary Iron Base Alloys, R. H. Graham, Manfred Wuttig Jan 1969

Additional Magnetic Disaccommodations In Ternary Iron Base Alloys, R. H. Graham, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.