급냉응고된 과공정 Al-Si 합금의 고온변형 거동에 관한 연구

초록

The high temperature deformation behavior of spray-formed Al-18wt.%Si-1.87wt.%Mg-0.085wt.%Fe alloy was studied by torsion testing in the strain rate range of 0.001-1 sec-1, and in the temperature range of 300-500 ℃. The relationship between stress, temperature, and strain rate is expressed using the Power law. The behavior of dynamic recrystallization is showed in 300-350 ℃, 1-0.1sec-1 and the behavior of dynamic recovery is showed in 450-500℃, 0.01-0.001sec-1. The size of Si particles is small when the temperature is low and the strain rate is high. The strain rate sensitivity(m) and the apparent activation energy(Q) indicate the dependence on strain rate and temperature for flow stress respectively. The hot ductility is high when m is high and Q is low. The maps of strain rate sensitivity and apparent activation energy suggest the optimum processing conditions.