论文部分内容阅读
对在两相区铸造进行半固态制浆所得AZ91D镁合金坯料的部分重熔工艺条件及组织演变进行了研究。结果表明 :AZ91D镁合金在两相区温度 (5 85℃ )静置 30min且在水冷铁模中浇注的两相区铸造半固态坯料 ,在5 75℃下保温 30～ 4 5min进行部分重熔时 ,其组织具有固相颗粒球化程度高、颗粒细小且粒度均匀、有效液相体积分数高等特点 ;坯料组织演变初始化阶段、球化阶段和集聚合并长大等 3阶段部分相互重叠。对特定原始半固态坯料 ,改变部分重熔温度 ,可缩短重叠区 ,扩大球化区 ,实现坯料重熔进程及组织形态的优化 ,从而增加工艺可控性和提高坯料的触变性。
The partial remelting conditions and microstructure evolution of the AZ91D magnesium alloy billet obtained by casting in the semi-solid state in the two-phase zone were studied. The results show that the semi-solid billets of AZ91D magnesium alloy are cast in the two-phase zone where the temperature of the two-phase zone (5 85 ℃) is still standing for 30 minutes and cast in water-cooled iron mold, and then partially remelted at 5 75 ℃ for 30 ~ 45 min The microstructure of the microstructure has the characteristics of high degree of spheroidization of solid phase particles, small particle size, uniform particle size and high volume fraction of effective liquid phase. The initial stage of microstructure evolution, the spheroidization stage and the agglomeration and growth stage overlap with each other. For a certain original semi-solid billet, changing the partial remelting temperature can shorten the overlap zone and enlarge the spheroidizing zone, so as to optimize the process of remelting the billet and optimize the morphology of the billet, thereby increasing the process controllability and improving the thixotropy of the billet.