An Innovative Two-Stage Reheating Process for Wrought Aluminum Alloy During Thixoforming

An innovative two-stage reheating process has been developed to improve the thixotropic behavior of semi-solid wrought aluminum alloy during thixoforming. The variation of the microstructural evolution mechanisms with temperature and holding time during a traditional process and two-stage reheating process are presented in this paper. A preferred semi-solid microstructure with spherical-like grains surrounded by a uniform liquid film was obtained in the two-stage reheating process. The semi-solid microstructure obtained via this two-stage reheating process had a number of features beneficial for semi-solid metal processing, including smaller equivalent diameters, a higher degree of sphericity, a lower coarsening rate constant of solid grains and a reduced amount of entrapped liquid compared with that produced by the traditional reheating process. These results indicate that the two-stage reheating process is a promising method for manufacturing wrought aluminum alloy during thixoforming.