Slip Systems and Their Critical Shear Stress in 3% Silicon Iron

Abstract

Single crystals of 3% silicon iron with controlled orientation were deformed in tension between 20°C and -196°C at various strain-rates. The orientation was systematically selected so that the maximum shear stress was in <111> direction on low index planes. The operative slip systems were examined by surface observation and analysis of yield stress. The result showed the existence of {112} <111> system as well as {110} <111> system. The temperature dependence of critical shear stress of the two systems was separately determined and that of {112} <111> system was stronger than that of {110} <111> system. The critical shear stress for slip is different by 5% between two opposite <111> directions on {112} plane. The strain-rate dependence of critical shear stress was also examined and found to be derived from the stress dependence of dislocation velocity.