摘要
随着等通道转角挤压(ECAP)次数的增加,Mg-8Li-1Al(质量分数,％)合金的室温拉伸强度和塑性同时增加,对应1,2,3,4次ECAP,合金的屈服强度分别为169,185,196和198 MPa,延伸率分别为12％,14％,25％和27％.微观组织分析表明, ECAP方法在细化两相组织、提高合金强度的同时,还改善了α相组织的均匀性和等轴性,并使各晶粒间的取向差逐渐增大.这种处在非平衡状态的、具有较大取向差的晶界结构,在室温拉伸变形过程中可激活晶界滑移或晶粒转动等变形方式,进而使材料的塑性随道次增加而得到提高.
Measurement of room temperature tensile properties of Mg-8Li-lAl (mass fraction, %) alloy processed by equal channel angular pressing (ECAP) shows that the strength and elongation increase simultaneously with increasing the passes of ECAP. To ECAP 1, 2, 3 and 4 passes, the corresponding yield stresses and elongations of the alloy are 169, 185, 196, 198MPa and 12%, 14%, 25%, 27% respectively. The analysis of the microstructures reveals that ECAP process could not only refine the α and β phases, but also improve the homogeneity of a phase microstructure and increase the misorientations between grains in both phases. This kind of grain boundaries which are in non-equilibrium state and with relatively large rnisorientation might stimulate new deformation modes, such as grain boundary sliding or grain rotation during the room temperature tensile tests, as a result, the ductility of the alloy was improved.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2003年第8期795-798,共4页
Acta Metallurgica Sinica
基金
国家自然科学基金项目50171027
国家重点基础研究发展规划项目G19990650
沈阳市科委国际合作项目20010167资助
关键词
镁合金
等通道转角挤压
拉伸性能
晶粒细化
magnesium alloy, equal channel angular pressing, tensile property, grain refinement
