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Theses/Dissertations

1969

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Articles 1 - 18 of 18

Full-Text Articles in Metallurgy

Contributions To The Specific Heat Capacity Of Nickel, Iron, And The Alloy Ni3Fe, Thomas Gilman Kollie Aug 1969

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 Cp of a ferromagnetic solid is assumed separable into six contributions - that due to the dilation of the lattice Cd, that due to the harmonic oscillations of the atoms Cvh, that due to the anharmonic oscillations of the electrons Cva, that due to changes in energy distributions of the electrons Cve, that due to changes in the magnetic coupling among the electrons Cvm, and that due to atomic rearrangements Cvw. 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 Jan 1969

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 …


The Effect Of Thermal-Mechanical Processing Of The Exfoliation Corrosion Resistance Of An Aluminum-Zinc-Magnesium-Copper Alloy, James Lawrence Spehr Jan 1969

The Effect Of Thermal-Mechanical Processing Of The Exfoliation Corrosion Resistance Of An Aluminum-Zinc-Magnesium-Copper Alloy, James Lawrence Spehr

Masters Theses

"The objective of this investigation was to evaluate the effect of thermal-mechanical processing on the exfoliation corrosion resistance of an aluminum-zinc-magnesium-copper alloy. the aluminum alloy used was commercially available 7178 alloy in two thicknesses, 0.390 inch thick and 0.250 inch thick. this material was reduced 10, 25 and 40% in thickness in both the annealed and solution heat treated conditions. The material was then aged to a high strength condition, T6, or T8, in the case of the material reduced in the solution heat treated condition. The effect of the thermal-mechanical processing on the exfoliation corrosion resistance was then evaluated …


Phase Equilibria And Thermodynamic Studies In The System Ca0-Fe0-Fe₂0₃₋Si0₂, Muharrem Timucin Jan 1969

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 …


Thermal Fatigue Testing Of Die Casting Die Steels, Kulwant Singh Sabharwal Jan 1969

Thermal Fatigue Testing Of Die Casting Die Steels, Kulwant Singh Sabharwal

Masters Theses

"Thermal fatigue is a form of surface failure produced by repeated thermal stresses and is the main cause of die retirement in the die casting industry. A general review of the fundamental and practical aspects of thermal fatigue as encountered in the dies, based on earlier published work, is given and preliminary experiments in an effort to set up a suitable method of testing to study this phenomenon are then described. In the present technique developed to create the thermal conditions experienced by a die steel in aluminum die casting, a small portion of one face of a cylindrical test-piece …


The Effect Of Small Additions Of Niobium Upon The Corrosion Rates And Electrochemical Potentials Of Iron In Hcl, Hf, And H₂So₄, Richard Lee Jones Jan 1969

The Effect Of Small Additions Of Niobium Upon The Corrosion Rates And Electrochemical Potentials Of Iron In Hcl, Hf, And H₂So₄, Richard Lee Jones

Masters Theses

"The valence of niobium ions going into solution was determined by dissolving the metal in hot HF and measuring the volume of hydrogen evolved. The corrosion rates of Nb, NbHx, Fe and Fe - Nb alloys were determined in various concentrations of NCl, H₂SO₄ and HF. The Fe and Fe - Nb alloy samples were made by using powder metallurgy techniques. It was found that a metal skin was produced on the surface of iron corrosion samples if the carbon content of the surface layer was lower than that of the core of the sample. The lower carbon …


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 …


Grain Boundary Self-Diffusion In Sodium Chloride, Kenneth Ray Riggs Jan 1969

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 (-Qb/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 …


Effect Of Hydrostatic Pressure On Anelastic Stress Relaxation In A Mixed-Alkali Silicate Glass, Young-Gil (Gilbert Y.) Kim Jan 1969

Effect Of Hydrostatic Pressure On Anelastic Stress Relaxation In A Mixed-Alkali Silicate Glass, Young-Gil (Gilbert Y.) Kim

Masters Theses

"The effect of hydrostatic pressure on the anelastic stress relaxation of a mixed-alkali silicate glass (0.05 Na₂O, 0.95 K₂O, 3 SiO₂) was studied at 75°C between ambient pressure and 6 kbar. The activation volume of diffusion was found to be - 4.2 cm³/mole. It is proposed that a reequilibration of the defect population at pressure gives rise to the negative activation volume of diffusion"--Abstract, page ii.


A Continuous Method For Determination Of The Evaporation Rate Of Zinc, Paul Alan O'Neill Jan 1969

A Continuous Method For Determination Of The Evaporation Rate Of Zinc, Paul Alan O'Neill

Masters Theses

"A method for determination of the evaporation rate of zinc using a continuous recording balance has been devised. Tests were carried out under an inert gas over the range 600°C to 750°C with a total pressure of 1 atmosphere. It was found that the rate of evaporation doubled with an increase of 50°C in this range. Scanning electron microscope photographs show the crystalline nature of the condensate and the presence of a thin oxide layer on some solidified test samples. This oxide layer reduced the rate of evaporation by retarding the zinc vapor escape from the evaporating surface"--Abstract, Page iii.


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. …


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 …


Calorimetry Of Room Temperature Deformed Copper, George Juri Filatovs Jan 1969

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 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.


Establishment Of A Torsion Pendulum And Its Evaluation, Ashwin Kantilal Ghatalia Jan 1969

Establishment Of A Torsion Pendulum And Its Evaluation, Ashwin Kantilal Ghatalia

Masters Theses

"A torsion pendulum apparatus has been constructed. The pendulum has been evaluated by studying the Zener relaxation in α brass. Three wire specimens of commercial alloy of Cu-Zn were used and the value of log decrement has been obtained by the method of free decay of the oscillations. The known Zener peak was observed"--Abstract, page ii.


The Electrodeposition Of Zinc; Changes In Current Efficiency And Surface Structure Resulting From Various Addition Agents, Haruhisa Fukubayashi Jan 1969

The Electrodeposition Of Zinc; Changes In Current Efficiency And Surface Structure Resulting From Various Addition Agents, Haruhisa Fukubayashi

Masters Theses

"An examination of the surface structure of zinc electrodeposited from an acid-sulfate solution was made by scanning electron microscopy techniques. The current efficiencies were also determined, to a lesser extent, in order to correlate the results with the surface structures. Commercial and pure zinc oxide were used to prepare the neutral zinc sulfate solutions. The starting solutions were in a range of acid and zinc concentrations commonly used in commercial practice. Changes in morphology resulting from addition agents such as animal glue, gum arabic, and sodium silicate are compared"--Abstract, page ii.


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 …


Anodic Oxidation Of Pure And D.S. (Dispersion Hardened) Lead In Sulfuric Acid Solutions, Rafael San Martin Aldazabal Jan 1969

Anodic Oxidation Of Pure And D.S. (Dispersion Hardened) Lead In Sulfuric Acid Solutions, Rafael San Martin Aldazabal

Masters Theses

"The anodic oxidation of pure and dispersion hardened lead in 1 N H₂SO₄ was studied potentiostatically in the range - 0.28 to 2.0 volts (SHE). The anode surfaces were observed at various stages on a scanning electron microscope and x-ray diffraction techniques were used to determine the phases present. It was established that by oxidation up to 0.25 v only PbSO₄ is obtained. At potentials between 0.25 and 1.57 v, PbO (tetragonal) is formed beneath the lead sulfate layer. At potentials above 1.57 up to 2.0 v, a layer of ßPbO₂ forms in the outermost part of the anode underlying …