Combined role of microconstituents (particles, eutectic fraction and its morphology) on the damage accumulation of three as-cast Mg–Ca–Sn alloys having distinctive microstructural features is studied. Flow stress normalized with that of a solid solution alloy brought out the sole contribution of microconstituents to the deformation. For identifying the influence of microconstituents on strain hardening rate, Kocks-Mecking analysis is utilized together with intermittent post-deformation microstructures. Comprehensive microstructural characterization as a function of strain facilitated to unravel the distinction in internal damage accumulation among the alloys. Further, the internal damage accumulation variation due to distinct variation in the microconstituents is attributed to the differences in hardening rate trends among the three alloys. The reduction in hardening rate is analyzed to occur due to damage accumulation through eutectic fracture or interphase cracking. Thus, the damage mechanism and its influence on strain hardening in cast magnesium alloys is proposed.

研究了微成分（颗粒，共晶分数及其形态）对三种具有独特微结构特征的Mg-Ca-Sn铸态合金的损伤累积的综合作用。用固溶合金归一化的流动应力充分发挥了微成分对变形的作用。为了确定微成分对应变硬化速率的影响，将Kocks-Mecking分析与间歇性变形后微结构一起使用。作为应变函数的全面微观结构表征有助于揭示合金内部损伤累积的区别。此外，由于微成分的明显变化而引起的内部损伤累积变化归因于三种合金之间硬化速率趋势的差异。分析表明，由于共晶断裂或相间开裂引起的损伤积累，导致硬化速率降低。因此，提出了铸造镁合金的损伤机理及其对应变硬化的影响。