Plasticity damage behavior caused by compression twins and double twins in rolled WE43 magnesium alloys

The WE43 sheets are prepared by single-passed rolling at 370 °C and 450 °C with total reduction of 40% and 50%, and the microstructure and mechanical properties of the sheets are contrastively investigated. The R370-40% and R450-50% alloys both exhibit non-recrystallized structures with high-density dislocations and strong basal texture. Many {101¯1} compression twins and {101¯1}-{101¯2} double twins are observed when rolled at 370 °C, while {101¯2} tensile twins are observed when rolled at 450 °C. The R370-40% alloy failures at a considerably low stain, while the ductility of R450-50% alloy is much higher than that of R370-40%. The orientation of compression twins and double twins is more favorable for the basal < a > slip, then a large deformation occurs inside twins and deformation incompatibility appears at the twin-matrix boundary in the subsequent plastic deformation, leading to the final failure. The low plasticity of R370-40% alloy is mainly caused by the activity of compression twins and double twins.