Abstract The tensile strengths of the as-extruded Mg–Al–Ca ternary alloys at both ambient and elevated temperatures are enhanced via adding a high content of Ca element up to 6 wt%. High-temperature strength of the present rare-earth-free Mg alloys can be even compared with those of the reported Mg-RE alloys. The as-extruded Mg–6Al–6Ca (wt. %, AX66) alloy exhibits a tensile yield strength (YS) of ~404 MPa and an ultimate tensile strength (UTS) of ~415 MPa at room temperature, and YS of ~225 MPa and UTS of ~265 MPa at 200 °C, respectively. For the AX66 alloy, the nucleation rates of dynamic recrystallized (DRXed) grains are larger than those of the AX62 and AX64 alloys due to the typical particle stimulated nucleation effect. A number of long-rod Al2Ca phase is dispersed at the grain boundaries of AX66 alloy, and a restricted degree of DRX is induced. Consequently, the majority ofα-Mg matrix exists in the as-deformed state involving a high density of subgrains. The combined effects of grain refinement hardening, texture hardening and precipitation hardening guarantee the high strength. Specially, numerous micron-scale bulk (Mg, Al)2Ca phases are found to distribute among matrix, which play a critical role in maintaining the high thermal-resistance.

中文翻译：

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通过增加 Ca 浓度提高 Mg-Al-Ca 锻造合金的抗拉强度

摘要 通过添加高达 6 wt% 的高含量 Ca 元素，挤压态 Mg-Al-Ca 三元合金在室温和高温下的拉伸强度均得到提高。目前的无稀土镁合金的高温强度甚至可以与报道的镁-稀土合金相比。挤压态的 Mg-6Al-6Ca（重量百分比，AX66）合金在室温下表现出~404 MPa 的拉伸屈服强度（YS）和~415 MPa 的极限拉伸强度（UTS）和~225 200 °C 时的 MPa 和 UTS 分别为~265 MPa。对于 AX66 合金，动态再结晶 (DRXed) 晶粒的成核率大于 AX62 和 AX64 合金，这是由于典型的粒子激发成核效应。在 AX66 合金的晶界处分散有许多长棒状的 Al2Ca 相，并引起有限程度的DRX。因此，大部分α-Mg 基体以变形状态存在，包括高密度的亚晶粒。晶粒细化硬化、织构硬化和沉淀硬化的综合作用保证了高强度。特别是，发现大量微米级块状 (Mg, Al)2Ca 相分布在基体中，这在保持高耐热性方面起着关键作用。