Effect of extrusion deformation and pre-twinning on the microstructure and mechanical properties of Mg-3Al-1Ag alloy

This study explores microstructure and mechanical properties of extruded Mg-3Al-1Ag alloy under varying temperatures and pre-compression. Higher extrusion temperatures caused grain coarsening and strength reduction, while the tensile yield strength (175 MPa), ultimate tensile strength (272 MPa) and elongation (22.7%) are best at 300°C via synergistic grain boundary strengthening, dislocation accumulation, and solute effects. Pre-compression introduced &lt;11 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mover> <mml:mn>2</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:math> 0&gt; tensile twins that enhanced tensile strength through dual mechanisms: grain refinement and crystallographic reorientation promoting pyramidal II &lt;c+a&gt; slip activation. Compared to direct tension, pre-compressed specimens showed distinct yielding governed by low-stress detwinning rather than conventional slip. The work reveals twin-induced texture modifications critical for activating non-basal slip, guiding magnesium alloy optimization through twin engineering.