Metallurgy Commons^™

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 Genesis Of Cellular Precipitation In Copper Rich Copper-Indium Alloys, Raymond Albert Fournelle

Doctoral Dissertations

"The morphology of cellular precipitation in a Cu-9.5at.%In alloy has been investigated by light and electron microscopy and x-ray and electron diffraction. Both cellular and general precipitation were observed to occur simultaneously in quenched and aged alloys while only cellular precipitation was observed to occur in isothermally aged alloys. Because of the presence of wide, vacancy depleted precipitate free zones in the vicinity of grain boundaries, general precipitation was observed to have no effect on the early development of cellular precipitation. Hence, the early development of cellular precipitation was found to be identical for both types of heat treatment. By …

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 …

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 …

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

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 …

Contributions To The Specific Heat Capacity Of Nickel, Iron, And The Alloy Ni3Fe, Thomas Gilman Kollie

Doctoral Dissertations

The specific heat capacity at constant pressure C_p of a ferromagnetic solid is assumed separable into six contributions - that due to the dilation of the lattice C_d, that due to the harmonic oscillations of the atoms C_vh, that due to the anharmonic oscillations of the electrons C_va, that due to changes in energy distributions of the electrons C_ve, that due to changes in the magnetic coupling among the electrons C_vm, and that due to atomic rearrangements C_vw. Expressions appearing in the literature for these contributions, which …

X-Ray Determination Of Lattice Parameters And Thermal Expansion Coefficients Of Aluminum, Silver And Molybdenum At Cryogenic Temperatures, Claude Lowell Woodard

Doctoral Dissertations

"A multiple exposure back reflection diffraction camera was designed to mount on the vacuum jacket of a pressurized helium gas "Cryomite". With this design it is possible to obtain six diffraction exposures on a single film at any temperature in the range of 180 to 25°K. temperatures within this range are reached in short intervals and exposure periods are less than 30 minutes in a 2.875 inch (73.03 mm) diameter camera. Some of the advantages of this design are; direct measurements, multiple exposures on a single film, short exposures, direct compensation of film length changes due to evacuation or processing …

Calorimetry Of Room Temperature Deformed Copper, George Juri Filatovs

Doctoral Dissertations

"An adiabatic anisothermal differential calorimeter for the study of room temperature deformed 99.999% pure copper has been constructed. An annealed and a deformed specimen were heated at a constant rate in adiabatic surroundings and the differences in energy released between samples was obtained. The control circuits were automatic. Deformation was by elongation ranging from 12 to 40%, and the corresponding energy found was from 1.9 to 5.3 calories/gram-atom. No recovery energy was found. The results obtained generally agree with published results and, in particular, verify Gordon's isothermal annealing results. It is proposed that the criteria for the presence of recovery …

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.

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 …

Grain Boundary Self-Diffusion In Sodium Chloride, Kenneth Ray Riggs

Doctoral Dissertations

"The diffusion of ²²sodium and ³⁶chlorine along tilt and twist grain boundaries in pure and calcium chloride doped sodium chloride bicrystals was investigated. No enhanced diffusion of ²²sodium along the grain boundaries was observed. Between 400°C and 500°C the chlorine grain boundary diffusion parameter, D'Δ, is described by D'Δ = (D'Δ)₀exp (-Q_b/kT), where (D'Δ)₀ is approximately 10⁻⁷ cm³/sec and Qb is 1.15 ± .30 eV. The grain boundary angle, the grain boundary character (tilt or twist), and the calcium chloride concentration appear to have no pronounced effect upon the observed chlorine grain boundary diffusion. The ionic movement …

Phase Equilibria And Thermodynamic Studies In The System Ca0-Fe0-Fe₂0₃₋Si0₂, Muharrem Timucin

Doctoral Dissertations

"A study of phase relations and thermodynamic properties of phases in the system CaO-FeO-Fe₂O₃-SiO₂ was conducted at 1450°C and 1550°C. The region of stability of the different phases was determined by microscopic examination of the specimens. The thermodynamic properties of liquid were determined by analyses of quenched samples equilibrated at oxygen pressures from about 10⁻¹¹ to 1 atm. Isothermal phase diagrams were constructed from data for 0, 5, 10, 20, and 30 weight percent silica sections of the CaO-FeO-Fe₂O₃-SiO₂ system, and the effect of temperature and increased silica additions on the oxygen solubility of the liquid oxides was measured. Multicomponent …

Effect Of Micelles On Flotation Of Metal Ions, Uriel Michael Oko

Doctoral Dissertations

"A study of the anionic surfactant, sodium dodecyl sulfate (SDS), and the dependency of the adsorption of divalent metal counterions such as copper and zinc at the air-water interface on its concentration in the solution, was undertaken in order to better understand the process of ion flotation. The study is divided into two broad categories, the first of which consists of the evaluation of the extent of aggregation of the surfactant molecules into micelles, and the effect of the divalent metal counterion concentration on this aggregation and on the critical concentration at which micelles start forming (cmc). This was accomplished …

Surface Self-Diffusion On Nickel (111) By Radioactive Tracers, James Ronald Wolfe

Doctoral Dissertations

"Surface self-diffusion coefficients have been measured by a radioactive tracer method over the temperature range 614⁰ to 840⁰C on nickel (111) surfaces characterized by LEED. Previously unrecognized tracer evaporation during surface diffusion resulted in restricted spreading of the tracer at higher temperatures. A theoretical treatment of the tracer evaporation phenomenon is presented and subsequently used in the analysis of the data. The temperature dependence of the surface self-diffusion coefficient (D_s) for nickel (111) can be represented, over the experimental temperature range, by a single Arrhenius type relationship...Arguments are presented to justify an adatom surface diffusion mechanism which is …

An Investigation Of The Induction Heating Characteristics Of Powdered Susceptors Dispersed In A Non-Conducting Medium, Robert Leon Wright

Doctoral Dissertations

"This investigation determined some of the induction heating characteristics of powdered magnetite, iron and ferrosilicon susceptor dispersed in silica sand which had been coated with thermosetting resin. The powdered susceptor particles in the mixture were heated by the field of an induction coil, consequently heating the resin coated sand and bonding the sand grains together.

It was found that the type, relative amount,and particle size of the susceptor were important variables to be considered in the induction heating characteristics. Hysteresis losses in the susceptor particles, which are a function of the coil current, frequency, and permeability, appear to be the …

Hydrogen Absorption And Corrosion Studies Of Zone-Refined Iron, Chang Don Kim

Doctoral Dissertations

"The lattice constants of zone-refined iron filings and iron whiskers are 2.86623 and 2.86626 Å at 25°C respectively. Their thermal expansion coefficients are both the same, 12.1 x 10⁻⁶ /°C at temperatures 10 - 65°C.

The influence of hydrogen on the lattice constant of iron was investigated and it was found that hydrogen has no effect (within the limits of errors) on the lattice constant of iron at room temperature regardless of the charging methods. However, at elevated temperatures hydrogen expands the iron lattice due to increased solubility of the gas. The lattice constant of iron in vacuum and in …

The Statistical Mechanics Of Kink Interactions, Michael Brewer Mcneil

Doctoral Dissertations

"Using a potential derived from continuum elasticity, the interactions between kinks on a dislocation line are studied as special cases of the problem of a one-dimensional system of interacting particles. By the use of constant pressure ensembles, the principal kink-interaction problems of physical interest are solved. The application of these solutions to the theoretical analyses of work hardening and internal friction is explored and comparisons made to previous work in which kink interactions were neglected; it is found that, as would be expected, variations of equilibrium kink populations with external stress cannot account for the Bordoni peak, which must therefore …

The Thermodynamics Of The Zno-Fe₂O₃-Fe₃O₄ System, Robert Lee Benner

Doctoral Dissertations

"The purpose of this investigation was to (1) experimentally locate certain phase boundaries in three isothermal sections of the zinc oxide - ferric oxide - magnetite phase diagram, (2) to experimentally determine some of the thermodynamic properties of the zinc oxide - ferric oxide - magnetite system, (3) to use the thermodynamic properties of the zinc oxide - ferric oxide - magnetite system to evaluate the pseudo-binary system between zinc ferrite and magnetite, (4) to construct a compound stability diagram for the zinc-iron-oxygen-sulfer system"--Introduction, Statement of the Problem, page [1].

A Thermodynamic Study Of The Zirconium-Sulfur, Titanium-Sulfur And Hafnium-Sulfur Systems In The Disulfide-Trisulfide Region, Norbert Achilles Vermaut

Doctoral Dissertations

"A static method was used to study the equilibria which exist between the higher sulfides of zirconium and sulfur at temperatures from 700° to 1000 °C. Both disulfide and trisulfide have been identified by chemical analysis and X-ray diffraction. There exists a two-phase region of 'ZrS₂' and 'ZrS₃'. The composition limit of the homogeneous disulfide phase appears to exist between ZrS_1.90 and ZrS_2.00. The lower composition limit of the homogeneous region of the trisulfide phase was established as ZrS_2.75.

An experimental method of Blitz and co-workers, i.e., the use of evacuated …

Lattice Parameters, Thermal Expansion Coefficients, Densities, And Imperfections In Silver And In The Alpha-Phase Of The Silver-Indium System, Samir Moustafa Riad

Doctoral Dissertations

“An investigation of structure insensitive properties (lattice parameters, thermal expansion coefficients, densities, and imperfections) of silver and the α-phase of the silver-indium system was suggested by the desirable uses for silver and its indium alloys.

Both silver and indium used were 99.999 per cent pure. The silver-indium alloys were prepared by melting both metals inside evacuated and sealed fused quartz tubes. The solidified alloys were annealed and then examined by X-ray diffraction for homogeneity.

This experimental work is divided into three main parts:-

I. X-ray diffraction investigation to determine the solid solubility limit of the Ag-In α-phase at 25° C, …

An Investigation Of The Deformation Textures Of Cobalt, Roy Carl Wilcox

Doctoral Dissertations

"Deformation textures of various cobalt structures as a result of cold rolling together with some annealing textures were studied. The textures of cobalt were determined using a modification of the Schulz-Decker Geiger counter technique. Pole figures of the (1011), (0001) and (1010) planes were constructed. Also, a study of the microhardness of cobalt was made.

Microhardness tests were performed on various cobalt structures, in both the cold rolled and unworked conditions. The microhardness was found to vary with the source of the cobalt, the crystal orientation, and the amount of deformation and twinning. Deformation lines about the hardness impressions diffused …

A Thermodynamic Study Of The Zirconium Sulfides, Andrew Hessler Larson

Doctoral Dissertations

"A hydrogen reduction technique was used to determine some thermodynamic properties of various zirconium sulfide phases. The equilibrium H₂S/H₂ ratios were determined as a function of temperature and composition of the condensed sulfide phases. The hydrogen sulfide content of the equilibrated gas mixtures was analyzed by an iodimetric titration procedure.

A detailed description is given for the method and apparatus used both in the preparation of the various sulfide phases and in their equilibration with a hydrogen-hydrogen sulfide gas mixture.

The composition ranger 59 to 67 atomic per cent sulfur was studied over a temperature range of …

Imperfections Within Ti₂O₃ And Tio₂ Phases In The Titanium-Oxygen System, Tatsuhiko Ejima

Doctoral Dissertations

“The hexagonal-rhombohedral Ti₂O₃ phase in the Ti-O system extends from 32.5 to 34.5% oxygen b.w., with the exact composition of Ti₂O₃ nearly in the middle of the phase. Seven samples of different composition within that phase were made, and the lattice constants (a and c) and the density of each sample were determined.

The plots of the constants against the composition of the samples revealed a deviation from Vegard’s rule when approaching the exact composition of Ti₂O₃. The lattice constants of this compound, obtained by graphical interpolation were; a_{25 …}

A Study Of The Recrystallization And The Mechanical Properties Of Indium, Louis John Reitsma Jr.

Doctoral Dissertations

"The recrystallization temperature and the mechanical properties of tensile strength, elongation, reduction in area and hardness were determined for 99.97% indium. Metallographic techniques were developed and stress rupture data were obtained.

Single crystals of indium were grown in a horizontal furnace with a traveling temperature zone, and sectioned in a strain-free manner, with an etch-cutter. Because of the low recrystallization temperature of indium, no further work was done on the single crystals.

The effect of recrystallization on electrical resistance, thermoelectric force, hardness, bending strength, crystallographic orientation and microstructure was studied. The range of recrystallization temperature for small amounts of cold …

An Experimental And Theoretical Investigation Of The Preferred Orientation In Deformed And Recrystallized Hafnium, David S. Gould

Doctoral Dissertations

"The research problem, as presented, therefore became two-fold; first to investigate and determine the feasibility of fabrication of hafnium and secondly to study the deformation characteristics of the material in light of the overall study of hexagonal metals aimed at the development of an overall general theory of plastic deformation. This appeared to envolve a study of the operating deformation systems in hafnium and the theoretical and experimental study of the textures resulting from plastic deformation. These were to be analyzed in comparison with the other hexagonal metals.

It became evident immediately that the research techniques which must be evolved …

A Thermodynamic Study Of The Titanium Sulfides, Reinhard Paul Abendroth

Doctoral Dissertations

"The determination of the thermodynamic properties of chemical compounds is in essence an experimental one. The purpose of this investigation was (1) to make an experimental determination of the thermodynamic properties of the titanium sulfides (2) to determine what sulfide phases are present in the titanium-sulfur system (3) to show the relationships between the various phases present"--The Problem, Statement of the Problem, page 3.

The Application Of Dynamic Adiabatic Calorimetry To The Copper-Nickel System From 50 To 620 °C, Richard E. Pawel

Doctoral Dissertations

Introduction: The accurate measurement of changes in thermal energy in the solid state has long been the subject of investigators in many fields. Knowledge of thermal effects can contribute greatly to fundamental studies and the general understanding of many phenomena, as well as being the basis of thermodynamic and theoretical work leading to a better comprehension of the behavior of metals and alloys. High temperature calorimetric methods for the solid state may be naively considered to be identical, at least in principle, with the familiar adiabatic or isothermal type calorimeters used extensively in the vicinity of room temperature. A wealth …

Preparation And Separation Of Metallic Chlorides, Norbert Felix Neumann

Doctoral Dissertations

"The use of chlorine and chlorine compounds as metallurgical reagents has long been known to the metallurgical industry. Recent developments in corrosion resistant metals and alloys as well as new equipment and techniques have led to a revival of chlorine processes. Many of the objections to the use of chlorine in metallurgical operations have been overcome and many are being reconsidered, as evidenced by the new processes in which chlorine and chlorides are the primary reagents. The Betterton process employs chlorine or lead chloride for the dezincing of lead. Ductile zirconium and titanium have been made by reducing their chlorides …

The Rate Of Dissolution Of Aluminum In Hydrofluoric Acid, Yen-Ngen Wang

Doctoral Dissertations

"Pure aluminum has a relatively low strength, and its use is, therefore, rather limited. However, the resistance of pure aluminum to the attack of acids and many neutral solutions is higher than that of less pure aluminum or most of the aluminum-base alloys. For this reason, alclad alloy sheets, are made with a coating of pure aluminum on one or both sides of an aluminum alloy core. The coating is metallurgically bonded to the core over the entire area of contact. Thus the coating electrochemically protects the core from corrosive attack.

Aluminum is more negative in the electrochemical series than …