Microstructural Development In a Spray Formed Aluminum-Silicon Carbide BasedMetal Matrix Composite

摘要

The aging response of an 8090-SiC composite at 190 deg C has been monitored usingmicrohardness tests, macrohardness tests and transmission electron microscopy(TEM). Intriguingly, it has been found that the composite does not exhibit increased aging kinetics when compared with a control 8090 alloy. Both the control alloy and the composite exhibit a two stage strengthening behavior which is attributed to the precipitation of Delta' (Al3Li) and S' (Al2CuMg). Quantitative microscopy of the composite has been initiated since it has been found that T2 (Al6CuLi3), precipitates on the SiC/matrix interface. Hence, the interfacial area per unit volume(Sv) is of the utmost importance. Finally, the effects of T2 precipitates, at the SiC/matrix interface, on the distribution of Delta' have been determined.