Search

This article investigates the correlation between {10 1 ¯ 2} tensile twins and loading paths in extruded AZ31 magnesium alloy. By compressing along the extruded direction (ED) (perpendicular to the grain c-axis direction) and tension along the extruded radial direction (ERD) (parallel to the grain c-axis direction) to generate {10 1 ¯ 2} tensile twins. Observing the evolution of twins characteristics in two loading paths, and each path was chosen on three strains to detect by the electron backscatter diffraction (EBSD) technology. The results show that by compressing along ED, there is significant better mechanical properties, but has better ductility in tension along ERD. The feature of twins number, twins area, twins nucleation and growth preferences within the sample are disparity. The process of {10 1 ¯ 2} twins nucleation and growth during tension, which was shown that twins tend to nucleate at low orientation angle grain boundaries and grow towards them. The number and area of twins are related to the effective interaction area between the force axis and the grain during loading, resulting in a ratio of 4:1 difference in the twins area inside the tensile sample compared to the same strain under compression conditions. [ABSTRACT FROM AUTHOR]

The effect of strain on the adiabatic shear behaviour of AZ31 magnesium alloy under high strain rate compression was studied using split Hopkinson pressure bar (SHPB). The microstructure of the specimen was characterised using optical microscopy and electron backscatter diffraction. The results indicate that the adiabatic shear sensitivity increased with the strain. The microstructure evolution of adiabatic shear deformation has been investigated. Firstly, a large number of twins and dislocations are formed and accumulate in the early stage of deformation. Subsequently, they transform into dynamic recrystallised grains, forming an adiabatic shear band (ASB) and ultimately leading to crack formation. The dynamic recrystallisation mechanism in the ASB involves twinning-induced dynamic recrystallisation (TDRX) and rotational dynamic recrystallisation (RDRX). This study has analysed the ASB mechanism, which provides a foundation for material selection and the design of magnesium alloys. [ABSTRACT FROM AUTHOR]