Loading path relevance of {101¯2} tensile twins in AZ31 magnesium alloy

This article investigates the correlation between {10 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mover> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:math> 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mover> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:math> 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mover> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:math> 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.