The microstructure evolution of Al-5Ce alloy prepared by strain-induced melt activation during semi-solid isothermal treatment process

摘要

The coarse grains and rough eutectic microstructure of Al-Ce alloy seriously damage its performance. In this study, Al-5Ce alloys with fine eutectic fibers and bimodal grain distribution were fabricated by strain-induced melt activation (SIMA) process. The results demonstrated that with increasing isothermal temperature and soaking time, the Al11Ce3 phase changes from coarsening to remelting and the alpha-Al grains size decreases due to decomposition by liquid droplets during the semisolid isothermal treatment. And during the subsequent quenching process, the high cooling rate leads to the solidification of fine alpha-Al grains and the refinement of eutectic fibers and fiber spacing when the Al concentration exceeds the upper limit of eutectic composition, which forms bimodal grains with fine eutectic fibers.