| dc.description.abstract | This thesis has three parts (A)ZK60 magnesium alloy grain refinement of superplastic ductility study (B) A6061 metal matrix composites and combination treatment using rolling -T6 strengthening effect of alumina particles (C) Plastic sheet studies of thermoforming applications.
Mechanical properties of superplastic magnesium alloy using a simple rolling process plus annealing to refine the grain size of magnesium alloy ZK60. This goal is effectively achieved, obtaining grains as fine as 3.7μm. Such a specimen shows an elongation of 642% and its ultimate fracture surface exhibits inter-granular separation and significant grain growth. Additionally, the effects of the specimen’s geometry and tensile test axis with respect to rolling direction on superplastic elongation is studied, which has not been done before.
Mechanical properties of aluminum matrix composites, Al-Si alloys, with such excellent properties as low weight, low thermal expansion coefficient, and high wear-resistance, are ideal materials for the automobile and aerospace industries. However, their applications have been hampered by the coarsening of the primary-Si particles in Al-Si alloys. In this study, the rolling-and-T6- treatments effect on A6061/Al2O3 metal-matrix composites is investigated. The A6061/Al2O3 metal-matrix composites with different amounts of reinforcing Al2O3 particles are examined in the aspects of wear resistance and hardness. Upon the T6 treatment, the hardness is enhanced in all cases and is summarized. The results suggest that the increase of Al2O3 particles reduce the wear rate. The possible reinforce mechanisms and the environmental -temperature effects are discussed. This improvement in wear resistance is due to the particle size refinement of silicon at a high percentage-roll-reduction.
Mass production of LCD TVs in the past, back cover part are using plastic injection molding mainly due to the finished product and the development of very large-size injection molding mold costly (tens of thousands of dollars), so using another conventional plastic molding - thermoforming , the production of very large, less product, is worthy of consideration, this thesis is based on computer-assisted analysis of the control thermoforming Implementing thickness distribution of the materials used for ABS plastic. The effects of the opening angle of friction materials in high temperature environments with the mold wall mold, will directly affect the trend variant materials, for use in this paper the finite element software package ANSYS / LS-DYNA binding experiments, analysis of the plastic sheet plastic molding process and to investigate the effect of the LCD TV cabinet thickness distribution of the final. ANSYS / LS-DYNA finite element software can provide mold design, before the actual molding parts do first thorough simulation analysis, and according to modify the shape of the contour of the mold, to serve and benefit to reduce the number of tests in order to shorten the product development process while reducing costs.
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