Microstructural refinement and corrosion resistance of low-alloyed Mg-Al-Mn-Ca thin sheets via optimized high-speed extrusion parameters

This study investigates the microstructural evolution and corrosion behavior of low-alloy Mg-Al-Mn-Ca magnesium alloys which were extruded into wide-thin sheets at high speeds. By optimizing extrusion parameters , specifically extrusion ratio and temperature, this research achieves a fine-grained microstructure and an improved dynamic recrystallization (DRX) fraction. FEM and EBSD analyses reveal that high-speed extrusion with controlled flow variations facilitates DRX without excessive grain growth, supporting enhanced corrosion resistance . Experimental results show that lower extrusion temperatures and ratios contribute to smaller grain sizes and more favorable textures, thereby enhancing corrosion protection through denser, more stable corrosion films. These findings indicate that Mg-Al-Mn-Ca alloys extruded under optimal conditions are capable of meeting the performance demands for corrosion-resistant magnesium alloy applications in industrial settings. • The total alloying contents of our alloy are less than 2%. • The thin sheets are hot extruded at a high-speed of 35 m/min. • Grain refinement compensates for the insufficient strength.