The Effect of Deformation Ratio and Heat Treatment Time on the Microstructure and Mechanical Properties of A356 Aluminium Alloy During SIMA Process

Abstract

The influence of Strain Induced Melt Activated (SIMA) parameters on the globularization of α-Al and microstructure in A356 aluminium alloy were investigated in the present study. After production of samples using conventional permanent mold casting and cold rolling at various reduction, they were heat treated at 590°C for different holding time to spherodize the microstructure. The results indicated that, the grains became smaller, more spherical and having a homogenous distribution by increasing the deformation ratio. Increasing the holding time in heat treatment results the growth of globular grains. The necessary strain for recrystallization is about 15% and the optimum condition was achieved in the samples were 15% rolled and heat treated for 15 minutes at semi-solid temperature, regarding the maximum shape factor and minimum globular grains size. Further increasing in holding time is responsible for grain growth and hardness decline.