双相Mg-Li合金的α→β相变及热加工性能研究  

Hot Workability of Dual-Phase Mg-Li Alloy withα→βTransformation at Elevated Temperatures

作　　者：冯英豪 孙朝阳[1,2] 徐斯诺 朱南洋 王青磊 王春晖 Feng Yinghao;Sun Chaoyang;Xu Sinuo;Zhu Nanyang;Wang Qinglei;WangChunhui(School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083,China;Beijing Key Laboratory of Lightweight Metal Forming,Beijing 100083,China)

机构地区：[1]北京科技大学机械工程学院,北京100083 [2]金属轻量化成形制造北京市重点实验室,北京100083

出　　处：《稀有金属材料与工程》2023年第4期1227-1237,共11页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(52175285,52161145407);Fundamental Research Funds for the Central Universities(FRF-BD-20-08A,FRF-AT-20-09,FRF-TP-20-009A2)。

摘　　要：在温度为250-400℃、应变速率为0.1-10 s^(-1)条件下进行了热压缩试验,研究了双相Mg-Li合金的热加工性能、显微组织演变和相组成。建立了整合加工和α-Mg相含量的最佳热加工窗口。结果表明,所建立的Arrhenius本构模型能够准确预测软化过程中的应力流动行为。通过对合金显微组织的观察,发现动态回复(DRV)、动态再结晶(DRX)和α-Mg相变是主要的软化机制。α-Mg相以球化和α-Mg相内析出的形式转变为β-Li相,尤其是在300℃以上相变现象显著。同时,DRX行为容易在β-Li相中发生,而在α-Mg相中会被抑制。基于动态材料模型和微观结构分析,获得最佳加工窗口:温度300-350℃/0.1-1 s^(-1)和温度250℃/0.1 s^(-1)。Hot workability,microstructure evolution,and phase composition of dual-phase Mg-Li alloy were investigated via hot compression test at 250‒400°C with strain rates of 0.1‒10 s^(-1).The optimum hot workability window integrating processing andα-Mg content maps was established.Results show that the established Arrhenius constitutive model can accurately predict the stress flow behavior during work softening.In addition,the microstructure of the alloy shows that dynamic recovery(DRV),dynamic recrystallization(DRX)andα-Mg phase transformation are the main softening mechanisms.α-Mg phase is transformed intoβ-Li phase in forms of both spheroidization and internal precipitation ofα-Mg phase,especially above 300°C.Meanwhile,the DRX process can easily occur inβ-Li phase,whereas in theα-Mg phase it is retarded.Based on the dynamic materials model and microstructure analysis,the optimal processing window can be obtained as 300‒350℃/0.1‒1 s^(-1)and 250℃/0.1 s^(-1).

关 键 词：MG-LI合金 热变形行为 动态再结晶 加工优化 相变 

分 类 号：TG146.22[一般工业技术—材料科学与工程]