Optimization of sintering conditions for Al/SiC composites fabricated by PM method and the effect of holding time at high temperatures on composite properties

Aluminum powder was mixed with three volume percents of SiC powder and compacted under appropriate pressure. The specimens were sintered at different temperatures and for different periods of time. Density measurements and hardness tests were used to determine optimum sintering conditions. Also since one of the main applications of these composites is at high temperature working conditions, optimally sintered specimens were held at a high temperature for different periods of time in order to simulate high temperature working conditions. The XRD and EDS results indicated the formation of deteriorate phase of Al4C3 at the interface of the matrix and SiC particles after 16 hr of holding at the high temperature. XRD results also showed that the amount of the Al4C3 aggregates increases with time whilst the gradient of this increment decreases since the release of Si atoms in Al matrix decreases the reactivity of Al matrix with SiC particles and the formation of more Al4C3.

Keywords:

Al/SiC Composite , sintering , interfacial reaction ,