Microstructural Evolution and Mechanical Properties of 7075 Aluminium Alloy during Semi-Solid Compression Deformation

Aluminium alloys are becoming increasingly popular due to the demands for high-performance lightweight components, and semi-solid metal processing (SSM) is a technique for forming near-net-shape and complex components with far fewer defects associated with turbulent filling. The deformation mechanisms of semi-solid 7075 aluminium alloy were studied through the direct partial re-melting method using as-extruded billets. It is found that inter-granular and intra-granular deformation occur simultaneously during compression under the semi-solid condition; the deformation of solid primary α-Al grains can compensate for the shrinkage of inter-granular liquid and increase the integrity of shaped parts. The intra-granular deformation at the final stage of SSM can change the morphology of spherical solid grains and induces sub-grain boundaries.