Microstructure of Semi-Solid 6063 Alloy Fabricated by Radial Forging Combined with Unidirectional Compression Recrystallization and Partial Melting Process

Abstract

Radial forging combined with unidirectional compression (RFCUM) is introduced in recrystallization and partial melting (RAP) to fabricate semi-solid 6063 aluminum alloy, which can be defined as a process of RFCUM-RAP. In this study, the microstructures of semi-solid 6063 alloy prepared by semi-solid isothermal treatment (SSIT) and RFCUM-RAP processes are investigated. The results show that, the solid grains of semi-solid alloy prepared by SSIT are large and irregular. However, solid grains of semi-solid billet prepared by RFCUC-RAP are fine and spherical. Additionally, during RFCUC-RAP process, with the increase of isothermal holding time, the shape of solid grain is more and more spherical, but the size of solid grain is gradually increased. To obtain ideal semi-solid microstructure, the optimal isothermal holding temperature and time are 630 °C and 5~10 min, respectively.