Microstructure and mechanical properties of variable-plane-rolled Mg-3Al-1Zn alloy

A flawless bulk AZ31 magnesium alloy with extensive mechanical twins was produced by variable-plane rolling, in which the sample was rotated 90° around its longitudinal axis between passes. The unique orientation relationship between the parent grains and the twin grains favours twinning during variable-plane rolling, which leads to the formation of extensive twins. Tensile testing revealed an excellent balance of mechanical properties, with a yield strength of 280 MPa and 15.5% elongation to failure. The significant strengthening originates from the effective blockage of glide dislocations by numerous conventional grain boundaries and twin boundaries. A weak double-peak (slightly off-basal) texture is formed during variable-plane rolling, which helps in achieving the desired level of ductility.