As the lightest structural metal material, magnesium alloy has the potential to replace aluminum alloy and steel parts, but its development is limited by problems such as poor plasticity, processing difficulties, and casting defects. In this paper, CaO and Ce-La misch metal(RE) were used as grain refiners in AZ91 and their effects on alloy microstructure and properties were investigated. In comparison with AZ91 alloy, the grain size decreased from 237.290 μm to 31.390 μm and 27.49 μm with the addition of CaO and RE, respectively and the proportion of the second phase decreased from 19.029% to 11.414% and 8.644%, respectively; the effect of CaO on grain size and second phase was only 0.6% and 2.77% lower than that of the RE, respectively. The refined grain made the maximum compressive strength and compressive yield strength of AZ91-CaO alloy and AZ91-RE alloy 82% and 67% (Ca-O) 97% and 112% (RE) higher than that of AZ91 alloy and the compression ratio of the mixed alloys were similar. Electrochemical experiments and salt spray corrosion experiments confirmed the two mixed alloys had similar properties. Although the mechanical strength properties of the AZ91-CaO alloy were slightly lower than AZ91-RE alloy, the 100× cost-saving and energy-saving of high-energy consumption vehicles support the use of CaO as a more suitable grain refiner material than RE elements for large-scale industrial production.

镁合金是最轻的结构金属材料，具有替代铝合金和钢制零件的潜力，但其发展受到可塑性差，加工困难和铸造缺陷等问题的限制。本文将CaO和Ce-La稀土金属（RE）用作AZ91的晶粒细化剂，并研究了它们对合金组织和性能的影响。与AZ91合金相比，添加CaO和RE的晶粒尺寸分别从237.290μm减小到31.390μm和27.49μm，第二相的比例分别从19.029％减小到11.414％和8.644％。CaO对晶粒尺寸和第二相的影响分别仅比RE低0.6％和2.77％。细化晶粒使AZ91-CaO合金和AZ91-RE合金的最大抗压强度和抗压屈服强度比AZ91合金和压缩比分别高82％和67％（Ca-O）97％和112％（RE）的混合合金相似。电化学实验和盐雾腐蚀实验证实了两种混合合金具有相似的性能。尽管AZ91-CaO合金的机械强度性能略低于AZ91-RE合金，但高能耗车辆的100倍成本节约和节能支持将CaO用作比RE更合适的晶粒细化剂材料大规模工业生产的要素。电化学实验和盐雾腐蚀实验证实了两种混合合金具有相似的性能。尽管AZ91-CaO合金的机械强度性能略低于AZ91-RE合金，但高能耗车辆的100倍成本节约和节能支持将CaO用作比RE更合适的晶粒细化剂材料大规模工业生产的要素。电化学实验和盐雾腐蚀实验证实了两种混合合金具有相似的性能。尽管AZ91-CaO合金的机械强度性能略低于AZ91-RE合金，但高能耗车辆的100倍成本节约和节能支持将CaO用作比RE更合适的晶粒细化剂材料大规模工业生产的要素。