Abstract
The age hardening behavior of SiC whisker reinforced Al-Li alloy which was by squeeze casting, has been investigated using Vickers micro hardness test, calorimetric technique and TEM observation. It was found that the Li concentration in the composites decreased slightly when the Al-Li melt was infiltrated into the SiCw preform. The age hardening sequence of SiCw/Al-Li alloy composites was essentially same as that of Al-Li matrix alloy. But the age hardening behavior of the composites was more accelerated with increasing the SiCw volume fraction at 373K, 423K and 473K than that of the unreinforced matrix alloy. It was considered that the dislocation density increased with increasing SiCw volume fraction because dislocations were generated due to differential thermal contraction of the matrix/SiCw during quenching after the solution treatment. Furthermore, it is made clear that the remarkable age hardening effect in SiCw/Al-Li composites was obtained by precipitation of very fine and high density of second phase δ' (Al3Li)in matrix of composites.
