Metallurgy Commons^™

An Electrolytic Polishing And Recrystallization Study Of Zinc And Zinc Alloys., Roy Ashley Smith

Masters Theses

"A Unitron hot stage and polarized light were used to enable direct observation of recrystallization in high purity (99.99 per cent) zinc and high zinc content alloys. Electrolytic polishing was investigated in an attempt to prepare unetched surfaces which would show good structural contrast under polarized light and thus permit structural changes occurring during recrystallization to be observed.

Kinetic data obtained from a sequence of photographs during each recrystallization trial showed typical sigmoidal isothermal reaction curves characteristic of a nucleation and growth process. It was determined that rates of nucleation and grain growth are a maximum over the same time …

A Study Of The Relative Electric Resistance Of Commercial Steels And Pure Iron, William Eugene Wistehuff

Masters Theses

"The change in relative electric resistance of five commercial steels, Armco Ingot Iron and Pure Iron were studied over the temperature range of 800°C to 1100°C in an attempt to correlate the phenomena of hot or red shortness with a change in the Electric resistance .

The results from the above resistance measurements were compared with mechanical tests of the same steels to show that at the point at which the iron sulfide liquid forms there is a definite change in the slope of the electric resistance vs temperature curve.

Also studied was a discontinuity in the electric resistance vs …

A New Method Of Making Stainless Steel Powder By Electrochemical Disintegration, Mohammed Maher Saad

Masters Theses

"This paper describes a new method of making austenitic stainless steel (18/8) powder by electrochemical disintegration. The method used an external direct current applied to a heat-treated stainless steel anode, and a platinum cathode in an electrolyte of an aqueous solution of 20% HNO₃ and 1% H₂SO₄ by weight respectively.

Special attention has been paid to the size distribution of sieve and sub-sieve sizes, and the following ranges were found: approximately one-half lies between the limits of 200 and 325 mesh, and one third is finer than 325 mesh, with the remainder about +200 mesh, average …

An Equilibrium Study Of The System Bi-S-H₂, Don Hie Lee

Masters Theses

"An experimental study has been conducted to determine the equilibrium behavior of the system Bi-S-H₂. The system was studied by equilibrating H₂-H₂S gas mixtures with Bi(l)- Bi₂S₃(s) two-phase mixtures at temperatures of 500°, 600°, 700° and 750°C in a circulating type equilibrium apparatus. The equilibrium gas mixtures were analyzed by a Fisher Gas Partitioner with a reproducibility of approximately 0.06 %.

A linear free energy equation has been derived from the results with an average deviation of ± 1 Kcal. This deviation is well within the accepted experimental accuracy for …

Determination Of The Standard Free Energy Of Formation Of Zr₃S₂, Peter E. Otten

Masters Theses

"The Knudsen effusion method was used to find the equilibrium magnesium pressure for the reaction

3 Zr (s) + 2 MgS (s) = 'Zr₃S₂' (s) + 2 Mg (v)

By using known standard free energy data for the formation of magnesium sulfide and by using the equilibrium magnesium pressure, the standard free energy of formation of Zr₃S₂ was calculated and could be expressed by the equation

Δ F° = -139,800 + 49.13 T cal/mole

in the temperature range 900 to 1100°C.

It was also found that Zr₃S₂ was the zirconium …

Crystal Habit Modification Of Sodium Chlorate, Michael R. Keegan

Bachelors Theses and Reports, 1928 - 1970

All single crystals have a particular habit or morphology. The crystal habit refers to the relative degree of development of crystallographic planes into surfaces which make up the external appearance of the single crystal.

In this paper, NaClO3 is used as a parent crystal. Its simple cubic habit is modified to tetrahedral by the use of impurities of SO4=, S2O3=, Cr2O7=, and NO3-. The degree of habit change is studied as a function of impurity concentration and temperature. The problem and phenomena are explained in terms of surface chemistry and thermodynamics.

Physico-Chemical Principles Of Sixteenth Century Metallurgy, Robert E. Johnson

Bachelors Theses and Reports, 1928 - 1970

Following a review of sixteenth century metallurgical literature and a discussion of Gibbs free energy, this thesis discusses thermodynamic considerations of galena (PbS) reduction by iron from a lead assay of this period. The importance of fluxes in this assay is emphasized. The discussion covers both equilibrium and non-equilibrium conditions at 1100 degrees Celsius. Possible substitutes for iron are also covered.

Information from twenty-one small controlled lead assays is correlated with the thermodynamic discussion to determine the purpose of each constituent in the assay.

The Beneficiation Of Titaniferous-Magnetite Sands, Ronald Lloyd Nordwick

Bachelors Theses and Reports, 1928 - 1970

The purpose of this investigation of beneficiation methods is to develop and study possible economic methods for recovering an iron-titanium concentrate of sufficient purity to meet metallurgical requirements for subsequent direct reduction to pig iron and a high titanium slag.

Stress-Corrosion Cracking Of Brass, Paul A. Fossey

Bachelors Theses and Reports, 1928 - 1970

the mechanism of stress-corrosion cracking of brass has been sought for many years. Investigators have proposed many mechanisms, but each of these mechanisms has always had several drawbacks. This paper presents an account of experimental work done in the laboratory on this subject and compares it to the work of previous investigations. It evaluates the mechanisms presented by investigators and shows the failures of these mechanisms. A theory of Nitrogen Embrittlement is presented and an evaluation of this theory with experimental work follows.

Experimental Arc Furnace Smelting Of Titaniferous Iron Sands From The Northern Oregon Coast, Allan P. Herring

Bachelors Theses and Reports, 1928 - 1970

This investigation is an attempt to experimentally smelt titaniferous iron sands from the Northern Oregon Coast in a laboratory arc furnace.

The Effect Of Ph Upon Chelation Reactions In Montmorillonite Clays, Joseph Michael Keane

Bachelors Theses and Reports, 1928 - 1970

The purpose of this thesis is to investigate several chelation reactions and determine the effect of variable pH upon these reactions.

An Investigation Of The Sintering Of Iron-Wire Compacts, George L. Vivian

Bachelors Theses and Reports, 1928 - 1970

A study of the sintering of iron has been made by observing the rate of bonding of iron wires wound on iron spools. The specimens were sintered at a constant temperature of 850c in vacuum furnaces capable of producing pressures of 10-5 to 10-4 mm of mercury, and the growth of the bond between wires was observed as a function of time.

It has been concluded that the volume-diffusion mechanism is strongly operating in the sintering of iron at 850c, but in an evacuated system, the evaporation-condensation mechanism also contributes to the sintering process.

Electrodeposition Of Antimony From Sulfide Melts, Mahendra N. Rana

Masters Theses

"A study of the current-potential relationships, and the electrodeposition of antimony metal was conducted for fused mixtures of Sb₂S₃-Na₂S, Sb₂S₃-Sb and Sb₂S₃-NaCl-KCl in the temperature range of 700° - 900°C. An attempt was made to determine the mutual solubility of molten antimony and Sb₂S₃-Na₂S melts. The microstructure of deposited metal was studied metallographically. Analysis of phases present in the matte mixture (Sb₂S₃-Na₂S) was made by x-ray diffraction patterns.

All investigations were carried out in …

A Study Of Segregation In Cast Aluminum-Uranium Alloys, B. L. Bramfitt

Masters Theses

"This investigation involves a photomicrographic study of the segregation resulting from the eutectic solidification characteristics of aluminum-uranium alloys, ranging from 5 to 30 weight percent uranium. The segregation can occur in either of two manners; the first, due to the gravitational forces acting upon the growing particles which nucleate in the melt and the second, due to the mode and rate of heat transfer through the material. It was found that segregation occurred only as the result of the latter factor due to the small volume of the ingot and the rapid rate of heat transfer. The segregation was measured …

A Determination Of Vapor Pressure Of Barium In The Thermal Production Of Barium Metal, Thomas A. Theobald

Masters Theses

The Knudsen effusion method was used to find the equilibrium reaction pressure of barium for the following reactions:
4BaO + 2Al - 3Ba + BaO·Al₂O₃ (l)
4BaO + Si - 2Ba + 2BaO·SiO₂ (2).
The resulting barium pressure for reaction (l) ranged from 0.27 mm. Hg to 1.77 mm. Hg in a temperature range of 940°C to 1086°C. The barium pressures for reaction (2) varied from 0.38 mm. Hg to 1.94 mm. Hg in a temperature range of 1000°C to 1086°C. The free energies of formation of BaO·Al₂O₃ and 2BaO·SiO₂ at 1087°C …

A Study Of The Chemical Kinetics, Activation Energy And Difference Effect On Beryllium Dissolving In Mineral Acids, Daniel Santhamurthi Gnanamuthu

Masters Theses

"The rate of dissolution of polycrystalline beryllium was studied in hydrofluoric, hydrochloric and sulfuric acids. Two samples of beryllium containing different amounts of beryllium oxide were used. The experiments were performed at temperatures ranging from 20 to 50°C, and at various acid concentrations. The kinetics of these heterogeneous processes conformed to a reaction order of approximately one in all the cases. Since the conditions of the surface were complex during dissolution, these might complicate the reaction. This might be due to the oxide layer, which is present as impurity.

The difference effect was determined at various acid concentrations at 25°C …

A Study Of Several Commercial Steels In The Red Short Range, Jorge Alberto Espana

Masters Theses

"The red short phenomenon present in steel, was studied by means of torsion tests at temperatures between 800 and 1200⁰C. Cold drawn bars of different compositions of steels were tested, and the number of turns to failure and maximum twisting torque were plotted versus temperature.

All the steels tested, exhibited to have a certain degree of red shortness. By comparing the curves and the respective chemical analyses, the detrimental effect of sulphur and lead and the beneficial effect of manganese, was established.

Microscopic examinations revealed the intergranular nature of the cracks in the red short range. Sulphur and oxide distribution …

A Study Of The Recrystallization And Polygonization Of High Purity Aluminum, Robert Leon Wright

Masters Theses

"Laue back reflection patterns were used along with visual examination in evaluating the characteristics of the annealed structure of high purity (99.99%) aluminum single crystals which had been deformed by elongation. It was found that the glide strain and annealing temperature are primary factors to be considered with respect to the structural changes occurring during annealing.

It was determined that the glide strain must be above a certain critical value to cause recrystallization; below the critical value polygonization will predominate in the annealed structure regardless of the annealing temperature.

The single crystals used in the investigation were grown by the …

A Survey Of The Influence Of Selected Sulfides On The Thermal Decomposition Rate Of Zinc Sulfate, L. G. Twidwell

Masters Theses

"The influence which ZnS, CdS, Cu₂S, PbS, and FeS has on the thermal decomposition rate of ZnSO₄ was studied by measuring the SO₂ gas evolved per unit of time for various ZnSO₄-MeS mixtures at 600°C, and analyzing the solid phases by means of X-ray diffraction patterns.

The SO₂ gas evolved upon heating the pellets was analyzed as a function of time by absorbing the gas in a solution of distilled water, H₂O₂, and NaOH, and measuring the time required for the SO₂ to neutralize the NaOH. The gas …

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 …

The Effect Of The Rolling Load On The Micro-Structure Of Low Carbon Sheet Steel, Jerry Lee Cadden

Masters Theses

"A Stanat 315, two high-four high, combination rolling mill is used to cold roll annealed, low carbon steel strips. A method of measuring the rolling load was presented. The method consisted of constructing a load cell using SR-4 strain gages attached to a steel column. The load cell was placed under the hold down screw of the rolling mill and a known load was applied. The stresses from this load were transferred to the mill housing where another SR-4 strain gage was located. The strain in the mill housing was recorded at the corresponding applied load. During rolling, the strain …

A Weight Loss Technique For The Determination Of Phase Boundaries, Robert Lee Benner

Masters Theses

"An apparatus has been designed and constructed that would continuously record the weight loss of a sample in a flowing inert atmosphere, at a constant temperature.

A technique has been developed to determine the phase boundaries of a binary phase diagram.

Alloys of the magnesium-nickel, cadmium-antimony, copper-cadmium, copper-zinc, and magnesium-zirconium systems were subjected to investigation to verify the operation and resolve a number of limitations of the equipment.

These investigations disclosed that the apparatus gave the best results with alloys having vapor pressures in the range between 1 and 35 millimeters of mercury"--Abstract, page 2.

Investigation Of The Platinum-Rich Portion Of The Platinum-Tantalum Phase Diagram, Bob Dean Browning

Theses and Dissertations

The Pt-Ta binary system was investigated at two isotherms;1000°C and 1500°C, and at eleven alloy compositions in the range of 50 to 100 atomic percent platinum. The alloys were examined by x-ray diffraction and metallography. Three intermetallic compounds, Pt₂Ta, Pt₃Ta, and Pt₄Ta were found to exist in this composition range. The Pt₄Ta intermetallic appeared only at the 1500°C isotherm. Platinum dissolved tantalum substitutionally to 90 atomic percent at 1500 °C and to approximately 80 atomic percent at 1000 °C.

Attempts To Grow Metal Single Crystals By Strain Anneal, Donald James Mcmillan

Bachelors Theses and Reports, 1928 - 1970

The growth of such crystals in the solid state eliminates these problems to a considerable degree. Therefore, the purpose of this study was to grow a metal single crystal of predetermined orientation in the solid state utilizing the strain-anneal method.

Chelation Reactions In Montmorillonite Clays, Donald Edward Mahagin

Bachelors Theses and Reports, 1928 - 1970

The purpose of this investigation was the study of reactions between the cations which are absorbed between the basal planes of montmorillonite clay and certain commercially-available organic reagents.

Isothermal Decomposition Of Austenite (In 1.4% Tungsten Steel) At Subcritical Temperatures, Samir Moustafa Riad

Masters Theses

"An experimental investigation was conducted in order to study the relationship between temperature, time and the decomposition of austenite in Tungsten steel of a given composition - and to plot the T-T-T Diagram for this steel.

The steel was prepared, homogenized and cut into identical specimens for further heat treatment and metallographic inspection. Precautions were taken to prevent these specimens from decarburizing during any heat treatment.

This experimental work may be divided into three main parts:-

I. Determination of the critical temperature range; i.e. the range of temperature Ae₁ and Ae₃ above which austenite is stable and below …

A Resistivity Study Of Hot Short Ferrous Alloys, Harold Alfred Koelling

Masters Theses

"Resistivity measurements were performed at elevated temperatures on four special ferrous alloys and one commercial iron. The alloys were pure iron, iron with .023 per cent sulfur, iron with .33 copper, iron with .32 copper and .024 sulfur. Other elements were held to the minimum amounts possible in order to determine the actual effects of sulfur and copper. The commercial alloy was Armco Iron.

Measurements of resistivity versus temperature were taken at slow heating rates to determine if the iron sulphide liquid film formed in the grain boundaries of red-short steels had any effect on the electrical resistivity"--Abstract, page 7.

A Preferred Orientation Study Of Sheet Formed By Rolling Copper, Nickel, Titanium And Tungsten Metal Powders, Martin Franklin Marchbanks

Masters Theses

"Pole figure scans of strip rolled from copper, nickel, titanium, and tungsten metal powders were made on samples taken across the width of the strip, and with various amounts of surface material removed, to determine if any preferred orientation existed. No preferred orientation was found in any of the samples examined.

The method used was a modification of the Schultz technique, using the Norelco Pole Figure Fixture, whose geometry and operation is described, in conjunction with the Norelco diffractometer.

Defocusing resulting during the run of a pole figure is discussed and a method for reducing this defocusing is described.

The …

Electron Microscope Study Of The Systems Cadmium-Cadmium Chloride And Lead-Lead Chloride, Dennis O'Neill

Masters Theses

"The nature of the dispersed phase in the cadmium-cadmium chloride and lead-lead, chloride systems were investigated with the electron microscope.

Preliminary experiments on preparing and examining the dispersed phase showed that it was most feasible to study the material by electron-microscopic examination of replicas made from the surfaces of the fractured materials. Melting apparatus and methods were chosen so that samples of the melts could be easily quenched to different temperatures and so that the samples could be easily fractured with a minimum of surface contamination. Of the conventional replicating techniques tried, that of carbon replicas pre-shadowed with chromium was …

A Study Of The Difference Effects On Alpha Solid Solutions Of Oxygen In Titanium Dissolving In Hydrofluoric Acid, Kuo-Chin Chuang

Masters Theses

"Alpha solid solutions of oxygen in titanium dissolving in hydrofluoric acid exhibited a positive difference effect with k values of 5.7, being independent of the concentration of HF, within the compositional range studied 0 to 5 w/o oxygen. This indicates that various TiO_x alloys are polarizable to the same extent by the same strength of anodic current in hydrofluoric acid.

The difference effect observed on TiO_x alloys dissolving in HF-HCl revealed that the effect is dependent on the oxygen content of the solid solution as well as on the concentration of HCl. The presence of HCl results in …