The reinforcement of an age-hardenable Al-Cr matrix alloy in situ and by SiC/Al2O3 particles: tailoring the interface

Abstract

Al-Cr alloys containing less than 0.75% Cr give rise to an age-hardening effect and the alloys also exhibited a good combination of strength and ductility properties. The achievable high toughness of these alloys led to an attempt to produce in situ composites with an Al-Cr solid solution as the matrix phase and excess insoluble intermetallics of chromium aluminides as the reinforcing constituent. The development of composites based on the Al-Cr matrix alloy with SiC and/or Al2O3 as the reinforcing phase was also attempted by a casting route. It was observed that the increase in strength was quite considerable even with a relatively good ductility. The precipitation behaviour and its kinetics in this newly developed composite were also studied by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM).