7537

7009

كارشناسي ارشد

شناسايي و انتخاب مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1391

سيزده،76ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمدرضا طرقي نژاد، علي شفيعي

9/12/91

حسين ادريس، احمد رضاييان

مهندسي مواد

ID7009

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Investigation of Microstructure Mechanical Properties and Workability of Al Al2O3 Composite Produced by Powder Metallurgy and Accumulative Roll Bonding Processes Abstract In this study aluminum matrix composites with 2 4 6 and 10 wt alumina were produced using powder metallurgy mechanical milling and vacuum hot pressing techniques then this was followed by hot rolling process Microstructure and mechanical properties of the samples were investigated by optical and scanning electron microscopes and tensile and shear punch and hardness tests respectively Microscopic evaluations of the hot rolled composites showed a uniform distribution of alumina particles in the aluminum matrix It was found that with increasing alumina content in the matrix tensile strength shear strength and hardness were increased and the percentage of tensile elongation and shear elongation was also decreased Scanning electron microscope was used to investigate aluminum alumina interfaces and fracture surfaces of the hot rolled specimens after tensile test Scanning electron microscope observations demonstrated that the failure mode in the hot rolled Al 2wt Al2O3 composite strips is a typical ductile fracture while the failure mode was shear ductile fracture with more flat surfaces in Al 4wt Al2O3 strips During hot rolling AMCs with 6 and 10 wt Al2O3 were fractured whereas strip composites with 2 and 4 wt Al2O3 were produced successfully Again these procedures have been done in second part But the amount of alumina content was changed to 0 2 0 4 and 0 8 wt Also for reducing of strain hardening effect due to mechanical milling degassing process has been done in 673 K for 30 minutes After accomplishment of hot rolling process on the samples they followed by accumulative roll bonding process The accumulative roll bonding process has been done successfully for 5 cycles The accumulative roll bonding process was used in this project as a new and effective method for manufacturing high strength and highly uniform aluminum alumina composite strips Microstructural evolution and mechanical properties of the resulting composites were investigated These composites show an excellent Al2O3 particles distribution in the aluminum matrix Shear punch investigation shown that ultimate shear strength and shear yield strength were increased with increasing the cycles of accumulative roll bonding Scanning electron microscope observations from shear punch ed surfaces show that with increasing the accumulative roll bonding cycles surface roughness were improved Keywords Aluminum matrix composite Powder metallurgy Vacuum hot pressing Mechanical milling Hot rolling Accumulative roll bonding Mechanical properties Workability Fracture surfaces Shear punch test Shear surfaces

محمدرضا طرقي نژاد، علي شفيعي

حسين ادريس، احمد رضاييان