超轻β固溶体Mg-11Li-3Zn合金的准超塑性与变形机理  

QUASI-SUPERPLASTICITY AND DEFORMATION MECHANISM OF ULTRALIGHT β SOLID SOLUTION Mg-llLi-3Zn ALLOY

作　　者：曹富荣[1] 丁桦[1] 王昭东[2] 李英龙[1] 管仁国[1] 崔建忠[3] 

机构地区：[1]东北大学材料与冶金学院,沈阳110819 [2]东北大学轧制与连轧自动化国家重点实验室,沈阳110819 [3]东北大学材料电磁过程研究教育部重点实验室,沈阳110819

出　　处：《金属学报》2012年第2期250-256,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目50974038和51034002资助~~

摘　　要：采用铸造和轧制的方法获得了1.2 mm厚密度为1.43 g/cm^3的超轻Mg-11Li-3Zn合金板材,在573 K和1.67×10^(-2)s^(-1)条件下拉伸获得了200%的延伸率,其在高应变速率下呈现准超塑性;在拉伸过程中试样发生显著的动态再结晶导致晶粒细化,晶粒尺寸由平均27μm减小到9μm;此条件下的应力指数为4.4,流动激活能112.6 kJ/mol.分析表明,573 K和1.67×10^(-2)s^(-1)条件下试样拉伸过程中的变形机理为晶格扩散控制的位错攀移.1.2 mm thickness sheets of ultralight Mg-llLi-3Zn alloy with a density of 1.43 g/cm3 was obtained by casting and rolling,the elongation to failure is 200%at 573K with 1.67xl0-2 s_1 tensile rate,which indicates high strain rate quasi-superplasticity.Significant dy- namic recrystallization and grain refinement occur at 573 K and 1.67xl0-2 s-1 under which the grain size turns from initial 27 /im into 9 /jm,the stress exponent is 4.4 and the activation energy for flow is 112.6 kJ/mol.It is considered that the deformation mechanism of Mg-llLi-3Zn alloy at 573 K and 1.67xl0-2 s_1 is dislocation climb controlled by lattice diffusion.

关 键 词：Mg-Li-Zn合金 准超塑性 力学性能 显微组织 变形机理 

分 类 号：TG113[金属学及工艺—物理冶金]