Impression creep behaviour of ultrasonically processed in-situ Al3Zr-Al alloy composite in as-cast condition

Abstract

Impression creep behaviour of Al3Zr/Al composites with varying amounts of Al3Zr particles was studied at different temperatures (543, 573 and 603 K) and stresses (113, 141 and 170 MPa). The uniform distribution of Al3Zr particles throughout the matrix was achieved by ultrasonication during casting. The microstructure of the composites was refined by the homogeneously distributed insitu formed Al3Zr particles. From the creep analysis, it was found that the stress exponent and activation energy values of the Al3Zr/Al composites were higher than that of the base alloy making them more creep resistant. Uniform dispersion of the in-situ Al3Zr particles in the matrix and the clean interface between them played an important role in the improvement of the creep properties of the composites. It was also observed that the creep property of the composites was improved with the increased amount of Al3Zr particles. The calculated activation energy and stress exponent values suggest that the creep mechanism is dislocation climb controlled by lattice diffusion.