The tensile creep anisotropy of a dilute-alloyed Mg-0.3wt%Ca sheet is investigated along the rolling direction (RD) and normal direction (ND). Strong creep anisotropy is shown between the RD and ND, owing to the easy twinning and the Ca-segregation along twin boundaries during creep loading along the ND. To weaken the creep anisotropy, hot-compression parallel to the RD-ND plane is performed and the continuous dynamic recrystallization mechanism induces a bimodal microstructure with the coexistence of unrecrystallized and recrystallized grains. The creep anisotropy is successfully weakened after hot-compression, and the creep resistance is also significantly enhanced along both loading directions. With the assistance of microstructural characterization, the weakened creep anisotropy is ascribed to the dislocation arrays in the interiors of recrystallized grains and the Ca-segregation along the boundaries of recrystallized grains. Compared to commercial Mg alloys with poor creep property and rare-earth alloyed Mg with high price, good creep performance and low production cost can be synchronously realized in the hot-compressed Mg-0.3wt%Ca alloy. Thus, this work proposes a new perspective for producing creep-resistant Mg alloys.

中文翻译：

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稀 Mg-Ca 合金中的拉伸蠕变各向异性及其弱化机制


研究了稀合金 Mg-0.3wt%Ca 薄板沿轧制方向 （RD） 和法向 （ND） 的拉伸蠕变各向异性。由于在沿 ND 的蠕变载荷过程中容易孪生和沿孪晶界的 Ca 偏析，因此在 RD 和 ND 之间显示出强烈的蠕变各向异性。为了削弱蠕变各向异性，进行了平行于 RD-ND 平面的热压缩，连续动态再结晶机理诱导了未再结晶和再结晶晶粒共存的双峰微观结构。热压缩后蠕变各向异性成功减弱，沿两个加载方向的抗蠕变性也显著增强。在微观结构表征的帮助下，减弱的蠕变各向异性归因于再结晶晶粒内部的位错阵列和沿再结晶晶粒边界的 Ca 偏析。与蠕变性能差的商用 Mg 合金和价格高的稀土合金 Mg 相比，热压 Mg-0.3wt%Ca 合金可以同步实现良好的蠕变性能和较低的生产成本。因此，这项工作为生产抗蠕变 Mg 合金提出了新的视角。