Microstructure and texture evolution of semi-solid 2A14 aluminum alloy billet prepared by SIMA method

In this study, semi-solid billets of 2A14 aluminum alloy were prepared using the strain-induced melt activation (SIMA) method, and the microstructural evolution under different compression ratios and deformation regions was investigated. Furthermore, the effects of isothermal temperature and time on the microstructural evolution during the semi-solid isothermal treatment (SSIT) process were also examined. The results indicate that after hot compression, the <111>||CD texture in the core of the sample is gradually replaced by the <101>||CD texture. Compared with samples compressed to 60 %, those compressed to 50 % exhibited finer grain size and a higher degree of spheroidization after SSIT; Based on the strain magnitude, the samples were divided into different deformation regions. The evolution of texture varied across regions during hot compression, and after SSIT, the average grain size (AGS) showed a decreasing–increasing trend from region A (low strain) to region D (high strain); Furthermore, finite element analysis was employed to evaluate the temperature gradient within billets of different shapes during SSIT, and the results indicate that annular billets are more suitable for practical applications in semi-solid forming; Based on the changes in AGS and roundness with isothermal temperature and time, it was finally determined that 570 °C is the optimal isothermal temperature for SSIT process, and the optimal isothermal time range at this temperature is 10–20 min; The coarsening behavior of semi-solid 2A14 aluminum alloy was characterized through the LSW equation. Furthermore, significant enrichment of Cu, Zn, Mg, and Si was observed at the grain boundaries after SSIT.