The combined and singular effects of Zr and Er addition on the microstructure, tensile and impression creep behaviour of the cast A356 alloy were investigated. The Zr and Er refined the α-Al dendrites and secondary dendrite arm spacing (SDAS) and modified the eutectic morphology. The simultaneous addition of Zr and Er exhibited the smallest α-Al dendrites and SDAS with a fibrous eutectic morphology, resulting in the highest yield (∼118 MPa) and tensile (∼190 MPa) strength, and the largest creep resistance. The stress exponent, and the activation energy, were within the range of 6.28–7.22 and between 121.6 and 148.2 kJ mol−1, respectively. The lattice self-diffusion climb-controlled creep was the dominant creep mechanism. The constitutive creep equation was developed for each alloy.

中文翻译：

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添加Zr和Er的Al-7Si-0.3Mg合金的拉伸蠕变性能

研究了 Zr 和 Er 添加对铸造 A356 合金的显微组织、拉伸和压痕蠕变行为的综合和单一影响。Zr和Er细化了α-Al枝晶和二次枝晶臂间距（SDAS）并改变了共晶形态。Zr和Er的同时添加表现出最小的α-Al枝晶和具有纤维状共晶形态的SDAS，导致最高的屈服强度（~118 MPa）和拉伸（~190 MPa）强度，以及最大的抗蠕变性。应力指数和活化能分别在 6.28-7.22 和 121.6 和 148.2 kJ mol-1 之间。晶格自扩散爬升控制蠕变是主要的蠕变机制。为每种合金开发了本构蠕变方程。