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Articles 1801 - 1830 of 2628

Full-Text Articles in Metallurgy

Anodic Dissolution Of Beryllium In Anhydrous Media, William Joseph James, Martin E. Straumanis Jan 1971

Anodic Dissolution Of Beryllium In Anhydrous Media, William Joseph James, Martin E. Straumanis

Chemistry Faculty Research & Creative Works

No abstract provided.


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.


An Age Hardening Study Of Magnesium-Thorium-Manganese Alloys, Kuldip Singh Chopra Jan 1971

An Age Hardening Study Of Magnesium-Thorium-Manganese Alloys, Kuldip Singh Chopra

Doctoral Dissertations

"The age hardening processes in Mg-3.5 wt.% Th-1.0 wt.% Mn and Mg-1.0 wt.% Th-1.0 wt.% Mn alloys have been studied by light and electron microscopy, and by electron and X-ray diffraction. At aging temperatures of 300ºC and below, G.P. zone formation rapidly hardens these alloys followed by the precipitation of disc shaped plates during averaging. During aging above 300ºC, no G.P. zones form and the disc shaped precipitate grows to very large sizes. The combined results of X-ray and electron diffraction indicate that the disc shaped precipitate has a Mg₃Cd (DO₁₉) type structure. The basal plane of the Mg₃Th discs …


The Effect Of 15% Mno On The Phase Relations In The System Cao-Feo-Sio₂ At 1450ºc, Aquil Ahmad Jan 1971

The Effect Of 15% Mno On The Phase Relations In The System Cao-Feo-Sio₂ At 1450ºc, Aquil Ahmad

Masters Theses

"A study was made of the phase relations at 1450ºC in the systems CaO-FeO-SiO₂ and CaO-FeO-SiO₂ -15% MnO, in equilibrium with metallic iron. The stability region of different phases was determined by microscopic examination and electron-beam microprobe analysis of the quenched specimens. The effect of 15% MnO on the liquid saturation boundary of the system CaO-(FeO+MnO)-SiO₂ was discussed in terms of the effect of MnO on slag making reactions in the Basic Oxygen Furnace steelmaking process"--Abstract, page ii.


The Effect Of Cathodic Protection On The Stress Corrosion Characteristics Of 300m Low Alloy Steel, John Pechonick Jan 1971

The Effect Of Cathodic Protection On The Stress Corrosion Characteristics Of 300m Low Alloy Steel, John Pechonick

Masters Theses

"The objective of this investigation was to determine if stress corrosion failure of 300M steel is accelerated by the application of cathodic protection. Testing was conducted on notch tensile specimens that were coated with vacuum cadmium, electroplated cadmium, and vacuum aluminum. All specimens were stressed and placed in an aqueous sodium chloride environment. The failure times for the specimens were monitored and graphs were drawn which characterized the stress corrosion resistance of 300M steel and the cathodic protection systems. Fractography techniques were used to study the failure surfaces to determine the type of failure mechanism. The results of this thesis …


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 …


Etch Patterns On Zone-Refined Fe, M. E. Straumonis, Chang-Soo Kim Jan 1970

Etch Patterns On Zone-Refined Fe, M. E. Straumonis, Chang-Soo Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Upon dissolution of zone-refined Fe in strong acids, mainly three kinds of corrosion patterns were observed in the crystallites of the sections. Regardless of the acids, the {110} plane always appeared on the three patterns in the form of smooth and even steps, ledges, or facets. The {112}, {122}, and {123} planes were also developed but to a much lesser degree. The {100} and {111} planes were not observed because grains of the respective orientation were missing on the sections. Attempts were made to explain the formation of the planes by taking into consideration the reticular density of the planes …


Imperfections In The Ag-In System (Alpha-Phase) And Lattice Parameters Of Cadmium Oxide, Prafulla Maganlal Vora Jan 1970

Imperfections In The Ag-In System (Alpha-Phase) And Lattice Parameters Of Cadmium Oxide, Prafulla Maganlal Vora

Masters Theses

"This thesis has been divided into two parts, namely, "Imperfections in the Ag-In System (Alpha-Phase)" and "Lattice Parameters of Cadmium Oxide." Imperfections in the Ag-In System (Alpha-Phase): It can be shown -- as in the case of the Cu-In α solid solutions -- that during quenching from the liquid state, strains are produced by the quenching process and, in addition, vacancies are quenched-in, in the Ag-In α-solid solutions. The number of vacancies present, measured by the decreased density of the alloys, is proportional to the indium content up to the solid-solubility limit. Upon heat treatment of the alloys, the thermal …


Electrode Reactions In Zinc Electrolysis, Ernest R. Cole Jan 1970

Electrode Reactions In Zinc Electrolysis, Ernest R. Cole

Doctoral Dissertations

"The effects of temperatures from 0°C to 50°C and current densities from 10 asf to 200 asf on the current efficiency in the electrolysis of pure zinc sulfate solutions (65 gpl Zn⁺⁺ - 200 gpl H₂SO₄) were determined. Pure platinum and platinum coated titanium anodes were used with an aluminum cathode. Platinum anodes were not inert at certain combinations of temperature and current density, and platinum acted as a low overvoltage impurity causing resolution of the cathode deposit. Orientation of the zinc deposits was found to vary with temperature and to have a distinct relationship to current efficiency. Preconditioning of …


The Oxidation Kinetics Of Liquid Lead And Lead Alloys, Thomas Edward Weyand Jan 1970

The Oxidation Kinetics Of Liquid Lead And Lead Alloys, Thomas Edward Weyand

Doctoral Dissertations

"Liquid lead and lead-silver alloys were investigated to determine the rates and products of oxidation in pure oxygen at temperatures of 350 to 600°C. The kinetic data were determined using a Cahn electro-balance. Liquid lead was found to follow a cubic rate of oxidation between 350 and 400°C. A parabolic rate was found at temperatures above 400°C. 0.496% silver and 2.258% silver alloys followed a cubic rate of oxidation from 350 to 550°C and tended to approach a parabolic rate of oxidation above this temperature. Silver additions were found to increase the rate of oxidation as compared to the pure …


The Smelting Of Lead Drosses, Humberto Adolfo Arzabe Jan 1970

The Smelting Of Lead Drosses, Humberto Adolfo Arzabe

Masters Theses

"The constitution of the matte and bullion obtained by the smelting of lead drosses coming from the cooling of lead blast furnace bullion was investigated by metallographic, chemical, electron-microprobe, and X-ray means. At smelting temperatures (1200°C to 1300°C) two liquid phases are in equilibrium. A liquid lead phase with low concentrations of copper and sulfur, and a lighter liquid matte phase containing a high concentration of copper and sulfur with some dissolved lead. On cooling to room temperature the matte precipitates cuprous sulfide, a eutectic mixture of cuprous sulfide and lead sulfide with a deficiency of sulfur, and metallic lead …


The Deformation Mechanisms In Sublimed Magnesium Under Cyclic Loading, Babu Narian Thakur Jan 1970

The Deformation Mechanisms In Sublimed Magnesium Under Cyclic Loading, Babu Narian Thakur

Doctoral Dissertations

"A detailed study of the deformation processes in sublimed magnesium under reverse bending fatigue in air at room temperature has been undertaken utilizing the light, scanning and transmission electron microscopy. The Principal deformation modes are the basal slip and {10Ī2} twinning. The proportion of twinning increases markedly with the increasing stress level and the number of cycles. The evidence for cross slip is seen on the basal slip bands. The extrusions are seen not only along the basal slip lines but also along the {10Ī2} twin boundaries. In the later stages of fatigue, the extrusions chip off producing a notch …


A Systematic Study Of Instrument Variables Upon The Accuracy Of Microprobe Analysis, R. A. Parr Jan 1970

A Systematic Study Of Instrument Variables Upon The Accuracy Of Microprobe Analysis, R. A. Parr

Masters Theses

"The purpose of this investigation was to study the effect of instrument parameter changes upon X-ray intensity measurements of the copper-manganese system. The parameters utilized in this study included: (1) polished, contaminated, and 600 grit surfaces ; (2) constant sample current and constant beam current modes; and (3) 15 KV, 20 KV, and 25 KV accelerating potentials. Inspection of the data disclosed three interesting points: (1) copper and manganese X-ray intensity measurements appear to be a linear function of composition in the 15 KV through 25 KV accelerating potential range; (2) electron backscatter measurements consistently show in a limited range …


Metallographic Study Of Phase Changes In Heat Treated Ductile Iron, Mahendra Vadilal Desai Jan 1970

Metallographic Study Of Phase Changes In Heat Treated Ductile Iron, Mahendra Vadilal Desai

Masters Theses

"Continuous cast ductile iron samples were hardened. It was found that carbide dissolved in the austenite faster than graphite and that this material requires higher austenitizing temperatures and longer austenitizing time than steels. Tempered microstructures were affected by the prior austenitizing treatment and it appeared that the amount of carbon dissolved in the austenite determined the tempered microstructure. Several attempts to determine the austenite grain size indicated that it is not as easy to determine in ductile iron as in steels. Two techniques, heat etching and an isothermal transformation method, were found to reveal prior austenite grain size. It was …


Spheroidization In Tool Steels, Sharad Gajanan Bankar Jan 1970

Spheroidization In Tool Steels, Sharad Gajanan Bankar

Masters Theses

"A carbon steel, W1, and four other alloy tool steels, namely, A2, H13, D3, and M2, were spheroidized by five different procedures. Any modification made in the treatments for an individual steel were suggested by the results obtained with these five procedures. The hardnesses and microstructures obtained were compared with steel samples annealed at a tool steel mill. The response given by different steels to various methods of spheroidization was studied. It was found that A2, W1, and D3 steels responded the best to the cycling method whereas the best response to the isothermal annealing was given by H13 and …


Investigations Of Several Variables In The Dwight-Lloyd Mcwane Ironmaking Process, James Orlan Hood Jr. Jan 1970

Investigations Of Several Variables In The Dwight-Lloyd Mcwane Ironmaking Process, James Orlan Hood Jr.

Masters Theses

"The Dwight- Lloyd McWane Ironmaking Process (D-LM) is the first commercial process of its particular type and one of the few commercial processes involving prereduction of iron ore in existence today. This presentation reviews some promising ironmaking processes which involve iron ore prereduction, with special attention being given the D-LM process. Although the D-LM process is continuous from iron ore to high quality molten cast iron, the research and discussion herein is limited to principal variables involved in the production of high quality carbonized pellets in the prereduction phase of the operation. The variables of process temperature and pellet carbon …


Cathodic Behavior Of Co, Co-Fe Alloys And Some Other Metals In Acids In A Cathodic Protection Arrangement, Ram Bajaj Jan 1970

Cathodic Behavior Of Co, Co-Fe Alloys And Some Other Metals In Acids In A Cathodic Protection Arrangement, Ram Bajaj

Masters Theses

"During cathodic protection of a corroding metal, electrons are forced into the metal by a sacrificial anode, a battery or a rectifier. These electrons, which constitute the suppressing or external current, are discharged (by H⁺ of the corrosive liquid) on the local cathode of the corroding metal decreasing the emf of the local cells, and, thus, reducing the cell current or the rate of corrosion of the metal. This process was studied in detail by finding out the relationship existing between the cell and suppressing currents. The study was made using two circuits: the cell circuit (representing the local current) …


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 …


Voids In Neutron Irradiated Aluminum, Nicholas H. Packan Jan 1970

Voids In Neutron Irradiated Aluminum, Nicholas H. Packan

Doctoral Dissertations

"Void formation in high purity aluminum resulting from irradiation to fluences between 1.5 x 10¹⁹ and 1.6 x 10²² neutrons/cm² (E > 0 .1 MeV) at a temperature of 55 ± 5ºC was studied, primarily by means of transmission electron microscopy. In particular the effects of neutron fluence and flux were examined, as well as the possible influences of both preexisting and transmutation-produced impurities. A very low concentration of voids (about 10¹²/cm³) resulted from irradiation to 1.5 x 10¹⁹ neutrons/cm²; they averaged about 150 Å in diameter. Void concentrations and sizes increased with fluence, reaching values of 6 x 10¹⁴ voids/cm³ …


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.


Diffusion Of Iron And Cobalt In Nickel Single Crystals, Charles Frederick Heuer Jan 1969

Diffusion Of Iron And Cobalt In Nickel Single Crystals, Charles Frederick Heuer

Doctoral Dissertations

"Diffusion coefficients of iron-59 in nickel have been determined in the temperature range 815°C to 1200°C. The temperature dependence can be represented by an Arrhenius type relationship,...The effect of the isotopic mass on the diffusion coefficient of cobalt in nickel has also been investigated. The isotope effect parameter, E, was found to vary from .26 to .84 over the temperature range 970.5°C to 1200°C. Both results are consistent with the single vacancy mechanism of diffusion. No evidence of divacancy contributions to the mass transport has been found"--Abstract, Page i.


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 …


The Iron-Holmium Binary System And Related Magnetic Properties, Gerald J. Roe Jan 1969

The Iron-Holmium Binary System And Related Magnetic Properties, Gerald J. Roe

Doctoral Dissertations

"The iron-holmium phase diagram was investigated to determine the alloying behavior of these two metals and to determine the magnetic properties of some of the iron-holmium alloys which formed intermediate phases. The iron-holmium binary system was determined by three experimental techniques, differential thermal analysis (DTA), x-ray diffraction, and metallography. A phase diagram with three eutectic points and four intermediate phases was constructed from the experimental data. The two phases, Ho₆Fe₂₃ and Ho₂Fe₁₇, melted congruently at 1322⁰C and 1343⁰C respectively. HoFe₂ and HoFe₃ melted incongruently at 1288⁰C and 1293⁰C respectively. Neutron diffraction investigations were made on the intermediate phases Ho₆Fe₂₃ and …


Precipitation Hardening Of A Mg - 3.5 Wt. % Th - 1. Wt. % Mn Alloy, Adolf Chun-Chiung Huang Jan 1969

Precipitation Hardening Of A Mg - 3.5 Wt. % Th - 1. Wt. % Mn Alloy, Adolf Chun-Chiung Huang

Masters Theses

"The precipitation process in a Mg - 3.5 wt. % Th - 1. wt. % Mn alloy during aging at 260⁰, 350⁰ and 400⁰C was determined principally by transmission electron microscopy. At 350⁰ and 400⁰C, general precipitation of the equilibrium Mg₄Th phase moderately hardens the alloy. No transition lattice of this phase was seen. The Mg₄Th precipitate forms initially as disc shaped plates parallel either to the prism or basal plane of the matrix...During prolonged aging at 400⁰C the plates lengthen into long laths on either of the above planes in the close packed direction...At 260⁰C an unidentified G. P. …


Thermal-Fatigue Of Type 304 Stainless Steel, Gajinder Bir Singh Arora Jan 1969

Thermal-Fatigue Of Type 304 Stainless Steel, Gajinder Bir Singh Arora

Masters Theses

"Thermal fatigue resistance of unrestrained samples of type 304 stainless steel has been investigated under different test conditions. The following studies are reported: (a) effects of heating and cooling rates on the initiation of cracks, (b) effects of upper and lower cycle temperatures on the initiation of cracks, (c) effect of water quenching and (d) the manner in which cracks initiated and propagated. It is shown that under cyclic conditions involving maximum temperatures up to 1000°C, the thermal fatigue life of the material decreases rapidly with rise in the maximum temperature of the cycle. The increase in the lower cycle …


The Effect Of Aging On The Exfoliation Corrosion Characteristics Of 7178 Aluminum Alloy, J. James Slavick Jan 1969

The Effect Of Aging On The Exfoliation Corrosion Characteristics Of 7178 Aluminum Alloy, J. James Slavick

Masters Theses

"The objective of this investigation was twofold: 1) to determine the effect of the quench-to-artificial aging delay period on the exfoliation corrosion of 7178 aluminum alloy subsequently aged at 250F for 24 hours and 2) to determine the effect of an initial aging treatment at 212F on the tensile properties and exfoliation of 7178 aluminum subsequently aged at 250F. Testing was conducted on 0.125 inch thick sheet. Quench-to-aging delay periods of 0 to 28 days, and initial artificial aging treatments at 212F for 24 and 48 hours were investigated. In addition, the effect of overaging T6 material at 320F for …