Effects of Tic, B4C and Al2O3 Nanoceramic Reinforcement Particles on Friction Stir Welding of AA7075

Abstract

The most optimal combinations of both physical and mechanical properties are produced by carefully choosing the matrix and reinforcement in a metal matrix composite (MMC).Due to their superior strength and corrosion resistance, precipitation-hardened aluminum alloy 7075 is mainly used in aerospace applications. In this study, Aluminium alloy 7075 metal matrix composites have been fabricated (three samples) by reinforced with nano ceramic particles at different weight ratios (1.0,1.0and 1.5wt. %) of Titanium carbide (TiC), (0.5, 0.0 and 0.0 wt.%) of boron carbide (B₄C) and (0.5,0.8 and 0.5wt. %) of Aluminium oxide (Al₂O₃) using friction stir casting process. Also, for those samples, friction stir welding process has been carried out. Microstructural analysis has been done by optical microstructures (OM).  Specimens for impact strength (based on ASTM E23 standards) have been prepared for the welded joints of aforesaid samples. The significant improvement of hardness (78 Hv) has been observed in weld sample-1, which has the combination of 1.0 wt.% of TiC, 0.5 wt.%of Al2O3 and 0.50 weight percent B₄C. But, the Impact strength of the Sample 1 is significantly decreased instead of increasing compare to samples 2 and 3. Finally, based up on the micro structural results, it was noted that significant improvement of fine grain structure by the reinforcement effect of nano ceramic particles with base alloy.