Effect of Strain Rate on the Microstructural Development in DC Cast Al-15Si Alloy

Abstract

Hot compression at 573K under different strain rates was conducted on DC cast Al-15% Si alloy. The effect of strain rate on the microstructure development was investigated. Microstructureal characteristics and deformation behavior of Al-15% Si alloy were discussed by analyzing of flow curves, optical microscope and electron back-scattering diffraction (EBSD). The results show that the peak and steady-state stresses are influenced by increasing of strain rate. The alpha-Al dendrits are almost disappeared and Si particle distribute homogeneously in the Al matrix with less of them cracked under every strain rate. The size of continuous dynamic re crystallized (CDRXed) grains decreases and the volume fraction of these grains increases with the strain rate increases. It is also observed that the fraction of HABs increases gradually and that of LABs decreases considerably as strain rate increases. It is realized that deformation under high strain rate help for CDRX to occur.