Metallurgy Commons^™

Mechanical Properties And Microstructure Examinations Of Aluminium-Steel Composites, Mervet Ibrahim Shenouda

Archived Theses and Dissertations

No abstract provided.

Solidification Of Aluminium Alloy Ingots, Hassan Abdel Kader Abdel Salam

Archived Theses and Dissertations

No abstract provided.

Autooscillations And Nonlinear Anelasticity, Manfred Wuttig, Tetsuro Suzuki

Materials Science and Engineering Faculty Research & Creative Works

In conclusion it can be stated that a novel phenomenon, a mechanical auto oscillation, has been described theoretically and shown to exist experimentally. These auto oscillations occur when a nonlinear anelastic solid is forced into large amplitude oscillations in the vicinity of a martensitic transformation. They manifest themselves as a low frequency auto modulation of the a martensitic transformation. They manifest themselves as low frequency auto modulation of the forced vibration of such a solid. © 1980.

The Effect Of Shielded Metal Arc Welding Process Variables On Delta Ferrite Control In Austenitic Stainless Steel Weld Metal, Ralph Eldon Long

Dissertations and Theses @ UNI

This study was to determine the effects of shielded metal arc welding on delta ferrite in austenitic stainless steel weld metal. The two objectives of the study were to determine: (a) what variables of the SMAW process affect the delta ferrite content or Ferrite Number of austenitic stainless steel weld metal, and (b) to what extent the Ferrite Number is affected by SMAW variables.

The research design was experimental with data collected from mechanically produced weld metal using a magnetic instrument calibrated in Ferrite Numbers (FN). The electrode alloys tested were 308, 308L, 316L and 347. The sizes of electrodes …

Phase Equilibria For Iron-Rich Fe-Cu-C Alloys: 1500 To 950°C, Krishna Parameswaran, Kenneth Metz, Arthur E. Morris

Materials Science and Engineering Faculty Research & Creative Works

Isothermal sections for the iron rich corner of the Fe-Cu-C system have been constructed at 1500, 1450, 1200, 1172, 1150, 1000, and 950°C. A ternary invariant point exists at 1172°C where an iron rich liquid, a copper rich liquid, austenite, and graphite coexist. The iron rich liquid contains 3.7 wt pct Cu and 4.0 wt pct C. The austenite contains 7.3 pct Cu and 1.6 pct C. The copper rich liquid contains 2.4 pct Fe, and apparently very little carbon. The diagrams are used to explain the phenomena of "inverse segregation" that occurs during the solidification of iron rich Fe-Cu-C …

An Experimental Study Of The Reactions Of Excited Neon Atoms In Pure Afterglow Plasmas Using Resonance Absorption Spectrometry, R. A. Sierra, J. Beverley Clark, A. J. Cunningham

Materials Science and Engineering Faculty Research & Creative Works

Resonance absorption spectrometry has been applied in a room temperature study of the reactions of excited neon atoms in pure afterglow plasmas. The pressure range 10-500 Torr was investigated. Lorentz broadened linewidths calculated using a simple classical interruption theory allowed fractional absorption signals as large as 98% to be analyzed and absolute excited-state concentrations to be determined. The first absorption studies of the decay of 1P1 excited atoms in neon afterglows are reported. Analysis of the decay profiles of the 3P2, 3P0 and 1P1 excited states allowed quenching rate coefficients for each state to be determined and the role of …

A Metallurgical Evaluation Of The Mi Vida Prospect: A Mixed Copper Sulfide-Carbonate Ore Body, Sells, Pima County, Arizona, Kevin Michael Kenney

Masters Theses

"A copper-prospect in south-central Arizona has been evaluated on a metallurgical basis. Primary chalcocite and secondary covellite, plus the copper oxides malachite and brochantite, constitute the economic mineralization. The deposit outcrops as a steeply dipping (70°SW), intensely brecciated, copper-bearing quartz vein with discontinuous lenticular ore shoots.

Acid leaching techniques alone and in conjunction with froth flotation utilizing four copper oxide specific collectors were used to evaluate the amenability of this ore to processing. Direct acid leaching was examined and found to be ineffective. Removal of the chalcocite by froth flotation with xanthate was easy and gave better results to subsequent …

Nonlinear Anelasticity And The Martensitic Transformation, Manfred Wuttig, Tetsuro Suzuki

Materials Science and Engineering Faculty Research & Creative Works

Zener's model of a standard linear solid is extended to include nonlinearities characteristic of metals and alloys in the vicinity of a martensitic transformation. The equation of motion of a nonlinear anelastic solid is derived and solved using van der Pol's method. The characteristics of the solutions indicate that auto-oscillations of finite amplitude can be excited externally. It is proposed that the streaming oscillations represent the beat between the external excitation and the auto-oscillation. © 1979.

Molybdenum Stability In Coal Slags At 1400⁰C: Corrosion Properties For Mhd Electrode Applications., Kenton Brian Wright

Masters Theses

"Molten coal slag corrosion studies conducted on molybdenum at 1400°C used static and stirred slag experiments and electrical current experiments to parallel electrode conditions of slagging duct MHD generators. Crucibles containing molybdenum and slag were exposed to combustion-type gases in a tube furnace. Carbon monoxide-carbon dioxide gas mixtures controlled oxygen partial pressures at selected values between 10^-11 and 10^-3 atm. Metallograph and microprobe examination of polished sample sections defined corrosion characteristics.

At 1400°C, molybdenum metal is stable below 10^-9 atm oxygen pressure. Molybdenum dioxide is stable at higher pressure, but volatile molybdenum trioxides prevent formation of stable …

Processing Of Copper Refinery Anode Slimes, Shrirang Anant Kulkarni

Masters Theses

"A study of commercial copper refinery anode slimes has been conducted to evaluate the separation of valuable metals contained in the slimes. The slimes contain substantial quantities of Ag, Sn, Au, Pb, and Cu. The values were present principally as AgCl, SnO₂, Au, PbSO₄, Cu and CuSO₄.

A Roast-Leach-Roast-Leach (RLRL) technique solubilized up to 91 pct of the Ag and 99 pct of the Cu from raw slimes.

The Pb-Sn separation was investigated using the following hydrometallurgical techniques: 1) DETA (diethylene triamine) leaching; 2) NaOH leaching; 3) (NH₄)₂CO₃ leaching; …

Pelletizing Of A Lead Sinter Machine Feed, Hung-Yang Tsai

Masters Theses

"A typical lead sinter machine feed can be pelletized in a drum pelletizer using tap water as a binding liquid. The green pellets produced have return sinter as cores, and an outer layer of new material and fluxes. The moisture content of the pellets produced is about 5%. The pelletizing procedure developed used raw materials from the Amax Lead Smelter, with only a minor amount of feed preparation. The importance of proper moisture control, use of binders, method of adding moisture, speed of pelletizing drum, etc. were investigated. The stability of pellets under extreme storage conditions was also determined"--page ii.

Recovery Of Lead From Lead Smelter Mattes, Cheng-Ping Chang

Masters Theses

"A by-product of lead smelting is a matte which consists mostly of lead and copper sulfides. Experiments were conducted to determine the feasibility of removing lead from molten matte by adding iron as a reducing agent. The effectiveness of iron at 1000 and 1100°C was a function of matte composition, but not of temperature except near iron saturation. The lead content of matte could be decreased to as low as 9.0 to 11.6 wt pct (2.3 to 3.0 at. pct) at 1000°C, depending on composition. The effect of oxygen in the matte on lead recovery from iron-saturated mattes was also …

Numerical Control Milling, Roger Schroeder

Graduate Research Papers

This research paper centers on two general problems:

1) Development of machine angles on the point-to-point NC mill by utilizing different combinations of feed rates on the X and Y axes.

2) Developing a learning activity package which includes a product to be produced by students on the numerical control milling machine that is safe, fast and inexpensive. The experiences gained in this activity will give the students a good working knowledge of numerical control principles.

The Effect Of Antimony, Chloride Ion, And Glue On Copper Electrorefining, Thomas J. O'Keefe, L. R. Hurst

Materials Science and Engineering Faculty Research & Creative Works

A study has been made to determine the effect of antimony, chloride ion, and glue on copper electrorefining. All deposits were made at a temperature of 65° C on a titanium cathode. Current densities of 398 A m-2 and 133 A m-2 were used. The deposits were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) to determine morphology and crystal orientation. Atomic absorption (AA) and Auger spectroscopy (AES) were used to study the chemical composition of the deposits and a simple bend test was used to determine structural integrity. It was found that when the antimony concentration in …

Disk And Strip Forging With Side Surface Foldower: Part 2: Evaluation Of The Upper-Bound Solutions, Ronald A. Kohser, B. Avitzur

Materials Science and Engineering Faculty Research & Creative Works

The upper-bound solutions developed in Part 1 are evaluated with regard to their ability to produce a lower value for required power (load, pressure, or work). Comparisons made with existing solutions such as the triangular field solution and one-zone bulge solution show that for strip, each solution has a domain of geometry and friction in which it is superior. The new solution produces a lower upper-bound for conditions of high interface, friction and relatively thin specimen, the area where fold over is the observed mode of flow. For solid cylindrical disks, the solution fails to improve upon existing analyses, but …

Effect Of Collagen And Chloride Additions On Electrolytic Copper Deposits, William P. Lorenz, Thomas J. O'Keefe, Carlo B. Sonnino

Materials Science and Engineering Faculty Research & Creative Works

The effects of collagen concentration and molecular weight on the morphology and crystal orientation of electrolytic copper deposits have been determined and compared. The effect of chlorides in the presence of collagen on the above properties has also been investigated. Three different molecular weight collagens were studied and the consumption rate of each was determined by chemical analysis of the electrolyte before and after electrodeposition. Two-hour deposits were made in an electrolyte containing the subject collagens in concentrations ranging from 1.2 to 38.4 mg 1-1. Scanning electron and light microscopes and X-ray diffraction were used to evaluate the electrodeposits. © …

Discussion, Ronald A. Kohser

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

The Effects Of Certain Impurities And Their Interactions On Zinc Electrowinning, Donald R. Fosnacht

Doctoral Dissertations

“The effects of germanium, antimony, arsenic, cobalt, glue, and free acid concentration were studied on both commercial and synthetic electrolytes. The effects of a single factor and the combined effects of multiple factors were elucidated. The temperature, zinc concentration, and current density were also varied. It was found that the acid concentration was the most critical factor when impurity levels were at normal plant solution concentrations. The ranges where the effect of the impurity became apparent were: greater than 20 ppb for antimony; 40 ppb for germanium; 120 ppb for arsenic; and 7-8 mg/l for cobalt for a solution containing …

Evaluation Of Organic Additives For Use In Zinc Electrowinning, R. C. Kerby, H. E. Jackson, Thomas J. O'Keefe, Yar Ming Wang

Materials Science and Engineering Faculty Research & Creative Works

Organic additives are used extensively in zinc electrowinning to assist in controlling the process. A cyclic voltammetry technique has been developed to provide a rapid, quantitative evaluation of the effectiveness of selected organic additives in minimizing the deleterious effects that impurities, such as antimony, have on zinc deposition. Results have indicated that animal glues are more effective than the other organic additives tested, which included several gums, enzymes, and amino acids, in relation to the current efficiency of zinc production. Of the various animal glues compared in this research, the most effective appeared to have average molecular weights in the …

Evaluation Of Organic Additives For Use In Zinc Electrowinning, R. C. Kerby, H. E. Jackson, Thomas J. O'Keefe, Yar Ming Wang

Materials Science and Engineering Faculty Research & Creative Works

Organic additives are used extensively in zinc electrowinning to assist in controlling the process. A cyclic voltammetry technique has been developed to provide a rapid, quantitative evaluation of the effectiveness of selected organic additives in minimizing the deleterious effects that impurities, such as antimony, have on zinc deposition. Results have indicated that animal glues are more effective than the other organic additives tested, which included several gums, enzymes, and amino acids, in relation to the current efficiency of zinc production. Of the various animal glues compared in this research, the most effective appeared to have average molecular weights in the …

Positron Lifetime As A Function Of Grain Size, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

Published data on positron annihilation lifetime in copper as a function of grain size have been analyzed to show that there is a linear relationship between the internal grain boundary surface area, per unit volume, S v, and the positron lifetime, τ. The analysis indicates that grain boundaries are important in the trapping of positrons. It is suggested that the slope of the resulting straight line, dS v/dτ, can be used to determine the annihilation rate of the grain boundaries. © 1977 Springer-Verlag.

Low Order Correction For Subsurface Contributions In Diffusion Experiments, D. Powers, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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

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

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

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

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

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.

A Method For Improving The Accuracy In Phase Change Heat Transfer Data Through Increased Precision In Thermophysical Property Determinations, John Philip Drummond

Mechanical & Aerospace Engineering Theses & Dissertations

Wind tunnel model materials typically have thermophysical properties that vary with both position and temperature. A numerical study using a finite difference representation of the heat conduction equation has been performed on several of these model materials to determine their thermal response under a specified heat loading. This study has confirmed the feasibility of using an effective thermophysical property to account for the existence of variable thermal properties when a model undergoes aero­ dynamic heating. The effective property, when used in the reduction of phase-change heat transfer data, forced agreement of the actual transient behavior of a model with the …

Analogy Between Spinodal Decomposition And Martensitic Transformation, Tetsuro Suzuki, Manfred Wuttig

Physics Faculty Research & Creative Works

The translation of the theory developed for the spinodal decomposition of a supercooled alloy to the language appropriate for the martensitic transformation is carried out. In the spinodal theory, the stability of the alloy with respect to the composition fluctuation is examined, while in the present theory the stability of the crystal with respect to the shear displacement fluctuation, the transverse phonon, is studied. The analogy to the spinodal theory requires the revival of the strain gradient energy term or the couple stress term, the presence of which has been a subject of controversies for a long time since Laval. …