M.Sc. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: In this study, effect of multi directional forging (MDF) on microstructure, mechanical and tribological properties of binary Al-7Si, ternary Al-7Si-4Zn and quaternary Al-7Si-4Zn-3Cu alloys was systematically investigated. These alloys were produced by permanent mould casting. MDF resulted in the breaking up Si particles and elimination of dendritic structure of the alloys. MDF gave rise to an increase in the yield and tensile strength with elongation to fracture of the alloys while it had no significant effect on their compression strength. After MDF, the hardness of the binary and ternary alloys exhibited a slight increase while this property of quaternary alloy decreased. The highest yield and tensile strength were obtained from the binary and ternary alloys with one cycle and quaternary alloy with two cycle MDF. While the alloys had a brittle fracture at homogenized state, they exhibited ductile type fracture after MDF. The MDFed ternary and quaternary alloys showed higher wear loss than their homogenized state. Their wear loss increased continuously with increasing applied load. Smearing and delamination were observed on the worn surfaces of the alloys, but smearing was determined to be the effective wear mechanism of the alloys at both homogenised and MDFed states.
Key Words: Al-Si Alloys, Multi Directional Forging, Severe Plastic Deformation, Mechanical Properties, Wear | |||||||||||||||||||||