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研究添加Zn元素对铸造Mg-7Y-3Sm-0.5Zr合金的显微观组织和力学性能的影响。蠕变测试的温度范围为200-300 °C,应力范围为50-120 MPa。在本研究的蠕变测试条件下,合金的蠕变激活能为156-221kJ/mol。采用光学显微镜、扫描电镜和透射电镜观察合金在蠕变过程中显微组织的演化。结果表明:尽管合金在250 °C以下有着相似的蠕变行为,仅添加1%的Zn元素就能使合金在300 °C和50MPa蠕变条件下的蠕变寿命从52.2h提高到152.8h,表明Zn元素能够提高合金的高温抗蠕变性能。加入Zn元素后,合金中形成的高温稳定相和片层状结构相是合金高温抗蠕变性能提高的根本原因。
The effects of Zn addition on microstructure and mechanical properties of cast Mg-7Y-3Sm-0.5Zr alloy were investigated. The creep test temperature range is 200-300 ° C and the stress range is 50-120 MPa. Under the creep test conditions in this study, the creep activation energy of the alloy is 156-221 kJ / mol. The microstructure evolution of the alloy during creep was observed by optical microscope, scanning electron microscope and transmission electron microscope. The results show that the creep life of the alloy can be increased from 52.2h to 152.8h at 300 ° C and 50MPa creep only with 1% Zn addition, although the alloy has a similar creep behavior at 250 ° C. Zn element can improve the high temperature creep resistance of the alloy. Adding Zn element, the high temperature stable phase and lamellar structure phase formed in the alloy is the fundamental reason for the high creep resistance of the alloy at elevated temperature.