Effects of Isothermal Process Parameters on the Microstructure of Semisolid Alsi7mg Alloy Produced by EPM

Abstract

The effects of isothermal process parameters on the microstructure evolution of semisolid AlSi7Mg alloy produced by electro-pulse modification(EPM) and partial remelting process were investigated using an image analysis software based on quantitative metallography. The results showed that long isothermal time could make the semisolid particles more globular, but the size of the particles would grow larger; high semisolid isothermal temperature would reduce the solid volume fraction and accelerate the spherical evolution of the solid particles. It was found that the optimal process parameters should be 590°C and 10-20min of isothermal temperature and time respectively based on the conditions of this paper. The mechanism of the particles’ formation was also discussed during the isothermal treatment.