Comprehensive analysis and manufacture of recycled aluminum based hybrid metal matrix composites through the combined method; sintering and sintering + forging

Abstract

Recycled AA7075 aluminum alloy and pure electrolytic copper were used as the matrix to manufacture new aluminum-copper metal matrix composites (ACMMCs). Powder metallurgy methods were used and the green compacts were finalized by sintering only and sinter + forging. Experimental and numerical investigation of recycled hybrid metal matrix composites manufactured by the two methods was performed. Al–Cu matrix combined with the reinforcements ZnO, Nb2Al and SiC. Two basic formulations were used where the contents Nb2Al and SiC was kept constant and the content of ZnO were 15 wt% and 30 wt%, respectively. The effects of these reinforcements used in the hybrid metal matrix composite structure on the mechanical and physical properties were investigated. The Nb2Al, SiC ratios used in the structure (chemical interaction in the internal structure, the effects on static-dynamic compression and wear behaviors) were kept constant, in particular the ZnO component (interactions with other components and their effects on electrical properties) were investigated. Micro-hardness analyses, surface scratch tests, quasi-static and dynamic compression tests were conducted. Also, electrical conductivity of the composites were determined. The effect of the composite's formulations and production method on the results were investigated. It was found when ZnO content was reduced the yield stress and ultimate strength values increased, but their resistance to impact loading reduced. Also, sinter + forged samples exhibited higher yield stress and ultimate strength than the just sintered samples. The damage and microstructural analyses were performed by Scanning Electron Microscope (SEM). Moreover, a non-linear numerical model was utilized to simulate quasi-static compression and dynamic compression (low velocity impact) behaviors of the composites for both formulations and manufacturing methods. Finite element simulations were performed using the ABAQUS™/Explicit dynamic finite element software. It was determined that there was a satisfactory agreement between experimental and finite element model results.