摘要
采用普通重力铸造法制备Mg-4Li-1Ca-4.1Al-0.5Si合金,考察合金在不同温度固溶处理1h、400℃固溶处理不同时间后的微观组织演变和显微硬度。结果表明,铸态合金由α-Mg基体、(α-Mg+AlLi)二元共晶、(α-Mg+AlLi+(Mg,Al)_(2)Ca)三元共晶及块状CaMgSi组成。其中,AlLi相呈细密层片状,沿晶界分布;(Mg,Al)_(2)Ca呈网状分布于AlLi层片中心,连同基体α-Mg形成三元共晶体。合金经1h固溶热处理时,350℃下AlLi相分解加剧形成小颗粒,(Mg,Al)_(2)Ca相形成颗粒或针状纤维。400℃时,(Mg,Al)_(2)Ca共晶相大量溶解,数量急剧减少,同时AlLi相略有长大。经400℃固溶处理5h后,(Mg,Al)_(2)Ca共晶颗粒数量急剧增加且开始偏聚长大;同时,AlLi再次溶解形成纳米溶质颗粒,均匀弥散分布于基体。合金经350℃×1h处理后硬度值最高,为105.3HV。
Mg-4Li-1Ca-4.1Al-0.5Si alloy was prepared by ordinary gravity casting method.The microstructure evolution and microhardness of the alloy after solution treatment at different temperatures for 1 h and 400℃ for different time were investigated.The results show that the cast alloy consists of α-Mg matrix,(α-Mg+AlLi)binary eutectic,(α-Mg+AlLi+(Mg,Al)_(2)Ca)ternary eutectic and bulk CaMgSi.Among them,the AlLi phase is in the form of fine layer and distributed along the grain boundary.(Mg,Al)_(2)Ca is ditributed in the center of the AlLi layer,and together with the matrix α-Mg forms a ternary eutectic.When the alloy is solution heat treated for 1h,the AlLi phase decomposes at 350 ℃ to form small particles,and(Mg,Al)_(2)Ca phase forms particles or needle-like fibers.At 400 ℃,the(Mg,Al)_(2)Ca eutectic phase dissolves in a large amount,and the amount is drastically reduced,while the AlLi phase grows slightly.After solution treatment at 400 ℃ for 5 h,the number of(Mg,Al)_(2)Ca eutectic particles increases sharply and begin to segregate and grow.At the same time,AlLi dissolves again to form nanosolute particles,which are uniformly dispersed in the matrix.The hardness of the alloy after treatment at 350℃ for 1h is the highest,which is 105.3 HV.
作者
刘星
边丽萍
侯洁
梁伟
LIU Xing;BIAN Liping;HOU Jie;LIANG Wei(School of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Key Laboratory of Advanced Magnesium Based Materials,Taiyuan 030024,China;Advanced Metal Matrix Composites Forming Technology and Equipment Engineering Research Center,Ministry of Education,Taiyuan 030024,China;Analysis and Testing Center,Taiyuan University of Science and Technology,Taiyuan 030024,China)
出处
《热加工工艺》
北大核心
2022年第2期117-120,共4页
Hot Working Technology
基金
山西省专利推广项目(2019015)
国家自然科学基金项目(514011143)
山西省青年科技研究基金项目(2014021017-1)
国家自然科学基金联合重点项目(U1810208)
国家自然科学基金重点项目(U1710254)
山西省重点研发计划项目(201703D111003)。
