Abstract
The strength of directionally solidified Ni3Al-Mo alloys was investigated in tension at temperatures ranging from room temperature to 1273K. The 0.2% flow stress showed the positive temperature dependence. The flow stress increased with increasing temperature, reached a peak at 973K and then decreased. The effect of Mo fiber on the strength was dominant at temperatures lower than 973K, but it became weaker above 973K because the strength of Mo fiber decreased.
The microstructures of deformed Ni3Al matrix changed at test temperatures. Below the peak temperature long straight dislocations, which appear be formed by cross slip, were found in the matrix. At temperatures higher than 973K three-dimensional networks of dislocations were formed, which indicates that the recovery process is more active.
