Investigation of deformation twinning under complex stress states in a rolled magnesium alloy

A specially designed semi-circular notch specimen was employed in the current study to generate the various strain conditions, including uniaxial, biaxial, shear, and plane strains, which was utilized to explore the evolution of different deformation twinning systems under complex loading conditions. Using in situ synchrotron X-ray diffraction mapping method, it was found that the extensive double twins were activated during loading, while nearly no extension twinning activity was detected. After the formation of {10.1} and {10.3} compression twins, they transformed into {10.1}-{10.2} and {10.3}-{10.2} double twins instantaneously at the early stage of deformation. The lattice strain evolutions in different hkls were mapped at selected load levels during the loading-unloading sequence. The relationship between the macroscopic straining and microscopic response was established.