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采用传统铸造方法分别制备了Φ10 mm和Φ90 mm Mg-9Li-3Al-2.5Sr(LAJ932)合金锭。在挤压温度260℃,挤压比28条件下对Φ90 mm合金锭进行挤压。分别分析和报道了铸态和挤压态LAJ932镁合金的微观组织和力学性能。探讨了该合金在挤压过程中的组织演变规律。研究结果表明:铸态和挤压态LAJ932镁合金均包括α-Mg(hcp)相,β-Li(bcc)相和Al4Sr相。Φ10 mm铸锭的组织比Φ90 mm铸锭组织细小得多。挤压过程中α-Mg相发生连续动态再结晶,而β-Li相发生非连续动态再结晶。挤压过程中,在hcpα-Mg相中形成{10 1 0}<10 1 0>织构,而bccβ-Li相中则形成{110}<101>织构。挤压过程中,LAJ932镁合金的强度和塑性均得到改善。挤压态Mg-9Li-3Al-2.5Sr(LAJ932)合金的抗拉强度达到235 MPa,屈服强度为221 MPa,延伸率为19.4%,合金展现出良好的力学性能。
The Φ10 mm and Φ90 mm Mg-9Li-3Al-2.5Sr (LAJ932) alloy ingot were prepared by the traditional casting method. Φ90 mm alloy ingot was extruded under the conditions of extrusion temperature of 260 ℃ and extrusion ratio of 28. The microstructures and mechanical properties of the as-cast and extruded LAJ932 magnesium alloys were analyzed and reported respectively. The microstructure evolution of the alloy during extrusion was discussed. The results show that both as-cast and as-extruded LAJ932 magnesium alloys include α-Mg (hcp) phase, β-Li (bcc) phase and Al4Sr phase. Φ10 mm ingot organization than Φ90 mm ingot microstructure is much smaller. Α-Mg phase during continuous dynamic recrystallization, while the β-Li phase discontinuous dynamic recrystallization. In the extrusion process, the {10 1 0} <10 1 0> texture was formed in the hcpα-Mg phase and the {110} <101> texture was formed in the bccβ-Li phase. During the extrusion process, the strength and ductility of LAJ932 magnesium alloy are improved. The tensile strength of the as-extruded Mg-9Li-3Al-2.5Sr (LAJ932) alloy reaches 235 MPa, the yield strength is 221 MPa and the elongation is 19.4%. The alloy exhibits good mechanical properties.