This study investigates the effects of billet homogenization temperature on the dynamic recrystallization behavior during high-speed extrusion and resultant microstructure and tensile properties of the Mg–5Bi–3Al (BA53, wt%) alloy. Two billets homogenized at 350 and 450 °C (350H and 450H billets) are extruded at a high speed of 69 m/min. The 350H billet has a relatively smaller grain size and a higher abundance of fine Mg₃Bi₂ particles compared to the 450H billet. During extrusion of the 350H billet, enhanced dynamic recrystallization occurs as a result of its finer grains and abundance of particles, while the growth of recrystallized grains is suppressed by the grain-boundary pinning effect of particles. Ultimately, the extruded 350H material is characterized by smaller grains, relatively greater number of Mg₃Bi₂ particles, and a higher internal strain energy than the extruded 450H material. The tensile strength of the extruded 350H material is higher than that of the extruded 450H material owing to stronger grain-boundary hardening, particle hardening, and strain hardening effects. The extruded 350H material also exhibits a higher tensile elongation as its smaller grains inhibit the formation of crack-inducing undesirable twins during tension. The results from this study demonstrate that a decrease in the homogenization temperature from 450 to 350 °C leads to improved strength and ductility in the high-speed-extruded BA53 material.

本研究研究了钢坯均质化温度对高速挤压过程中动态再结晶行为的影响，以及 Mg-5Bi-3Al (BA53, wt%) 合金的微观组织和拉伸性能。以 69 m/min 的高速挤出在 350 和 450 °C 下均质化的两个钢坯（350H 和 450H 钢坯）。_{350H方坯晶粒尺寸相对较小，细Mg 3} Bi ₂丰度较高颗粒与 450H 钢坯相比。在 350H 钢坯的挤压过程中，由于其晶粒更细、颗粒丰富，动态再结晶增强，而再结晶晶粒的生长受到颗粒晶界钉扎效应的抑制。_{最终，挤压 350H 材料的特点是晶粒较小，Mg 3} Bi ₂的数量相对较多颗粒，以及比挤压 450H 材料更高的内部应变能。由于更强的晶界硬化、颗粒硬化和应变硬化效应，挤压 350H 材料的抗拉强度高于挤压 450H 材料。挤压 350H 材料还表现出更高的拉伸伸长率，因为其较小的晶粒在拉伸过程中抑制了导致裂纹的不良孪晶的形成。该研究的结果表明，均质化温度从 450°C 降低到 350°C 可以提高高速挤压 BA53 材料的强度和延展性。