Simple Shear Extrusion of Al/Al2O3 Composite Prepared by Stir Casting and Hot Forging

In this study, aluminum/alumina composites with 3 and 5 vol% reinforcement particles were manufactured via stir casting and hot forging; they were severely deformed by the simple shear extrusion (SSE) technique. Three SSE dies with different distortion angles were utilized in this work. The SSE-ed samples with alpha = 22.5 degrees were then fractured after one pass, while SSE-ed samples with alpha = 8 and 10 degrees were deformed up to thirteen passes, successfully. Microstructural evolution, porosity percentage and micro hardness parameters were investigated after each process. Shear punch test was then used to evaluate the mechanical properties. Additionally, the applied force and stress/strain distributions were evaluated by the finite element method (FEM) code via ABAQUS (R) simulation software in different passes. Moreover, the effect of the SSE process on the fracture behavior of the commercial Al and aluminum matrix composite was studied. The results showed that the effective strain was increased with increasing the number of SSE passes and distortion angles, while the applied force was decreased with increasing the number of passes. Microstructure, bonding quality, hardness and porosity percentage were also improved by using forging and SSE processes. During the process, ultimate shear strength was enhanced with increasing the amounts of effective strain; also, shear elongation percentage was decreased. Further, SEM observations showed that the fracture mode in the SSE-ed commercial Al sample was a typical ductile one, whereas the fracture mode was nearly shear ductile with more flat surfaces in the Al-5 vol% Al2O3 specimens.