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Development Of An Advanced Aluminum Thermal Analysis System For The Characterization Of The 319 Aluminum Alloy Solidification Process., Todd J. Stockwell
Development Of An Advanced Aluminum Thermal Analysis System For The Characterization Of The 319 Aluminum Alloy Solidification Process., Todd J. Stockwell
Electronic Theses and Dissertations
Thermal analysis is the study of heat evolution as a molten alloy transforms to a solid. Studying the evolution of heat results in a temperature, time relationship in the form of a cooling curve. Specific characteristics of the 319-aluminum cooling curve are described and related to specific metallurgical properties. Variations in the cooling curves represent changes within the solidification of the alloy and are correlated to changes in the metallurgical properties. In the present work, an aluminum thermal analysis system (AITAS) is constructed to withstand the rigors of day to day foundry conditions. Complete automation has been introduced to reduce …
Microstructural Studies Of Wear Mechanisms In Cast Aluminum Alloys., Mustafa Elmadagli
Microstructural Studies Of Wear Mechanisms In Cast Aluminum Alloys., Mustafa Elmadagli
Electronic Theses and Dissertations
The microstructural basis of wear and surface degradation mechanisms in Al-Si alloys has been investigated in order to improve the current understanding of the requirements for wear resistant aluminum alloy design. The wear behaviour of three commercial alloys namely: a sand cast A390 (Al-18.4%Si), a spray formed Al-25%Si, and a die cast 383 (Al-9.5%Si) have been investigated. Dry sliding wear tests were performed using a block on ring type tribometer under controlled environments. The experiments were performed in a load range between 0.2 N and 300 N at a constant speed of 1 m/s. The testing environments were a dry …
Adhesion And Material Transfer Between Aluminum And Surfaces Coated With Diamond-Like Carbon And Other Coatings., Erkan Konca
Adhesion And Material Transfer Between Aluminum And Surfaces Coated With Diamond-Like Carbon And Other Coatings., Erkan Konca
Electronic Theses and Dissertations
Adhesion and transfer of aluminum to the surfaces of tool coatings that are potential candidates for dry machining of Al-Si alloys were investigated. First, 319 Al alloy pins were tested against various industrial coatings (CrN, TiB2, TiAlN, TiN, and TiCN) using a pin-on-disc tribometer. The analyzed Scanning Electron Microscope (SEM) images of the wear tracks were used to rank the coatings according to the amount of Al transferred on their surfaces. In general, the TiB2 and TiCN coatings exhibited the least amount of Al transfer on their surfaces compared to the other coatings. Second, the tribological behaviour of the diamond-like …
Characterization Of Electrode Wear Morphology Via Sequential Life Testing., Bobby Kamal Singh Athwal
Characterization Of Electrode Wear Morphology Via Sequential Life Testing., Bobby Kamal Singh Athwal
Electronic Theses and Dissertations
Brass layer formation and hardness degradation during the resistance spot welding of hot-dipped galvanized steel was characterized for a number of copper-based electrode materials and electrode geometries as part of an overall program to increase electrode life through the analysis of electrode wear. Metallographic, composition, and hardness examinations were conducted on electrodes subjected to single-current and stepped-current life tests. The electrode wear sequence was documented via sequential life testing, in which electrodes were removed for testing and examination at established intervals during single-current testing. Testing was conduced on truncated-cone and ball-nose electrode geometries. Electrode materials included a Class 2 precipitation-hardened …
Wear And Scuffing Resistances Of Eutectic Aluminum-Silicon Alloys And Aluminum-Silicon Based Composites, Hongbo Wang
Wear And Scuffing Resistances Of Eutectic Aluminum-Silicon Alloys And Aluminum-Silicon Based Composites, Hongbo Wang
Electronic Theses and Dissertations
The existing information in the open literature suggests that the eutectic Al-Si alloy may be one of the best candidate materials for the sleeveless automotive engine block application. Dry sliding wear tests have been conducted using the block-on-ring wear machine on the near eutectic Al-Si alloys (13.2% Si) with the same chemical compositions, in which two were as-cast alloys had needle-shape Si particles, and the other two T6 heat treated alloys had round-shape Si particles. The T6 heat treatment has efficiently improved the hardness of the Al matrix, refined the Si particles in comparison to the as-cast alloys. The reciprocating …
An Investigation Of The Electrolytic Plasma Oxidation Process For Corrosion Protection Of Pure Magnesium And Magnesium Alloy Am50., Yueyu Ma
Electronic Theses and Dissertations
In this study, silicate and phosphate EPO coatings were produced on pure magnesium using an AC power source. It was found that the silicate coatings possess good wear resistance, while the phosphate coatings provide better corrosion protection. A Design of Experiment (DOE) technique, the Taguchi method, was used to systematically investigate the effect of the EPO process parameters on the corrosion protection properties of a coated magnesium alloy AM50 using a DC power. The experimental design consisted of four factors (treatment time, current density, and KOH and NaAlO2 concentrations), with three levels of each factor. Potentiodynamic polarization measurements were conducted …
Formation And Properties Of The Peo Coatings On Aluminum-Silicon Alloys., Linlin Wang
Formation And Properties Of The Peo Coatings On Aluminum-Silicon Alloys., Linlin Wang
Electronic Theses and Dissertations
Plasma electrolytic oxidizing (PEO) of aluminium alloys is an advanced technique to deposit a thick and hard ceramic coating on a number of low Si content aluminium alloys. The rapid growth in the tribological applications of high Si cast Al-Si alloys has been motivating this study, i.e., development of a PEO coating with high wear resistance and low friction for high Si content cast Al-Si alloys. In this research, the effect of substrate materials (i.e., silicon contents, Chapter 4) and process parameters (Chapter 5) on the PEO coating formation, microstructure, and composition were investigated in details. An oxide/graphite composite coating …
Low Temperature Environmental Degradation Of Zirconia Ceramics., Zhenbo Zhao
Low Temperature Environmental Degradation Of Zirconia Ceramics., Zhenbo Zhao
Electronic Theses and Dissertations
The low temperature environmental degradation (LTED) of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) has been prevented, or at least retarded, by using both bulk doping and surface doping methods with either cation, or anion, stabilizers. The introduction of both mullite and alumina into 3Y-TZP by a bulk-doping method was found to be effective in suppressing the tetragonal-->monoclinic transformation induced by water during hydrothermal treatment thus giving rise to better mechanical properties. The beneficial effects of alumina on the phase stability of the 3Y-TZP ceramic are considered to be due to the increase in the elastic modulus of the constraining matrix, …