The effect of strain rate on the microstructural evolution of pure Mg during ECAE

Samples of 99.9% pure, as-cast magnesium (Mg) were processed by Equal Channel Angular Extrusion (ECAE) using up to four passes the BC route, a temperature 250 °C, and three different extrusion rates 0.127, 0.381, 0.762 mm/s. The microstructures textures resulting samples characterized Electron Backscatter Diffraction (EBSD) as function pass rate. average grain size was reduced significantly approximately 30 μm after second when extruded at all rates, but then it varied depending on rate third fourth passes. two slower yielded 30–40% increase in passes, while fastest mm/s maintained relatively consistent presence twins also with rate, slowest producing greater volume fraction than intermediate larger is attributed microstructure maintaining favorable orientations for twinning lower need strain accommodation higher