双相LZ91镁锂合金超塑性变形行为及组织演变  

Superplastic tensile properties and microstructure evolution of dual-phase LZ91 Mg-Li alloy

作　　者：刘金学 解海涛 郭晓光 肖阳 赵红亮[2] 关绍康[2] 白明华 LUI Jin-xue;XIE Hai-tao;GUO Xiao-guang;XIAO Yang;ZHAO Hong-liangGUAN Shao-kang;BAI Ming-hua(Zhengzhou Light Alloy Institute Co.,Ltd.,Zhengzhou 450041,China;School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,China;LONGi Solar Technology Co.,Ltd.,Xi’an 710000,China)

机构地区：[1]郑州轻研合金科技有限公司,郑州450041 [2]郑州大学材料科学与工程学院,郑州450001 [3]隆基乐叶光伏科技有限公司,西安710000

出　　处：《中国有色金属学报》2022年第3期713-720,共8页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51974281);中铝公司2019年青年科技人才启明星计划项目(2019MXJH13);“郑州1125·聚才计划”创业领军团队项目(2015091)。

摘　　要：采用铸造、挤压、冷轧和退火的方法,获得了双相LZ91镁锂合金板材,并通过OM、SEM、TEM和拉伸实验,研究了双相LZ91镁锂合金板材在200~300℃、应变速率1.0×10^(−2)~1.7×10^(−4) s^(−1)条件下的超塑性变形行为、显微组织演变和空洞长大机制。结果表明:双相LZ91镁锂合金在285℃、1.7×10^(−4) s^(−1)条件下的最大超塑性达到485%;拉伸过程中微观组织由初始的β-Li再结晶相和α-Mg条带状相向等轴的β-Li相、α-Mg再结晶相以及β-Li基体中的次生α-Mg纳米相进行演变;空洞主要形核于α/β两相晶界处,变形早期在应力作用下,空洞沿着晶界扩散长大,是扩散控制的长大机制;变形后期在周围材料的塑性变形作用下,空洞被拉伸长大,是塑性变形控制的长大机制。The dual-phase LZ91 alloy plate was prepared by vacuum casting,extrusion,cold rolling and annealing.The superplastic behavior,microstructure evolution and cavity growth mechanism of LZ91 Mg-Li alloy were investigated using OM,SEM,TEM and tensile tests in the temperature range 200℃to 300℃and strain rate of 1.0×10^(−2) s^(−1) to 1.7×10^(−4) s^(−1).The results show that the maximum superplasticity of dual-phase LZ91 Mg-Li alloy reaches 485%at 285℃,1.7×10^(−4) s^(−1).During the superplastic deformation,the microstructure evolves from initialβ-Li recrystallized phase and bandedα-Mg phase to equiaxialβ-Li phase,α-Mg recrystallized phase and nanoαMg precipitates inβ-Li matrix.The cavitation is mainly nucleated at theα/βinterface.In the early stage of deformation,the cavity diffuses and grows along the grain boundary due to the promotion of stress,which is the diffusion-controlled growth mechanism.While,the cavity is stretched under the plastic deformation of the surrounding material in the later stage of deformation,then the growth mechanism is plastic deformationcontrolled.

关 键 词：双相LZ91镁锂合金 超塑性 空洞 显微组织演化 

分 类 号：TG146.22[一般工业技术—材料科学与工程]