Microstructure and Mechanical Properties of Al-20 wt% Si-9 wt% Fe-1.2 wt% Nb Alloy by the Addition of 6 wt%Ni

This study demonstrates the potential of the Al-Si-Fe-Nb system as a new precipitation hardenable aluminium alloy by addition TM alloying elements. The mentioned aluminium alloy was prepared with nominal composition Al-20Si-9Fe-1.2Nb (at wt %) as a conventional cast alloy, and again prepared with composition Al-20Si-9Fe-1.2Nb-6Ni (at wt %) to be compared with each other in order to investigate the effect of Ni addition. Experimental samples of these alloys are synthesised and analysed by optical microscopy (OM) and Micro-hardness techniques. Results show that the three-phase region of Al-Si-Fe-Nb alloy were -Al, primary Si and -Al (FeNb) Si phases, while the four-phase region of the alloy after Ni addition were -Al, primary Si, -Al (FeNiNb) Si and -Al (FeNiNb) Si phases. The highest hardness of 114 Hv was obtained for the Al-Si-Fe-Nb-Ni alloy which is relatively higher than that of Al-Si-Fe-Nb alloy (101 Hv).