(1. 兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室，兰州 730050；
2. 兰州理工大学 有色金属合金及加工教育部重点实验室，兰州 730050)
摘 要: 通过半固态等温热处理，研究保温温度和保温时间对Mg-7Zn-0.3V镁合金把固态组织演变的影响。结果表明：保温温度和保温时间对Mg-7Zn-0.3V非枝晶组织的演变有重要的影响。提高保温温度或是延长保温时间，可以使Mg-7Zn-0.3V中的非枝晶组织转变为更加细小且分布均匀的球状颗粒。当保温温度过高或是保温时间过长时，半固态颗粒会出现合并和长大，其主要的演变机制与Ostwald熟化规律相符合。Mg-7Zn-0.3V合金的最佳等温热处理工艺是：保温温度605 ℃，保温时间40 min，非枝晶颗粒的平均尺寸为48.5 μm，形状因子为1.26。
关键字: Mg-7Zn-0.3V镁合金；半固态等温处理；非枝晶组织；演变机理
（1. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China;
2. Key Laboratory of Non-ferrous Metal Alloys and Processing, Ministry of Education, Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:The effects of remelting temperature and holding time on microstructural evolution of Mg-7Zn-0.3V magnesium alloy were investigated by semi-solid isothermal heat treatment. The results indicate that the holding temperature and holding time have significant effects on microstructural evolution of the Mg-7Zn-0.3V alloy during isothermal temperature process. By increasing the holding temperature or prolonging the holding time, the non-endritic structures in Mg-7Zn-0.3V can be transformed into smaller and more uniform spherical particles.When the holding temperature is too high or holding time is too long, the semi-solid particles will combine and grow up, the microstructural evolution mechanism is consistent with the rule of Ostwald ripening mechansim. The best parameters of isothermal heat treatment are 605 ℃ holding temperature and 40 min holding time, obtaining the semi-solid microstructure with the average partial size of 48.5 μm and the roundness of 1.26.
Key words: Mg-7Zn-0.3V magnesium alloy; semi-solid isothermal heat treatment; non-endritic structure; evolution mechanism
