异步轧制Mg-3Zn-2(Ce/La)-1Mn合金的微观组织及织构演变

Microstructure and texture evolution of differential speed rolled Mg-3Zn-2( Ce/La)-1Mn alloy

为了研究镁合金经异步轧制后的微观组织及织构演变,使用4种不同异速比对挤压态的Mg-3Zn-2(Ce/La)-1Mn合金进行异步轧制试验。结果表明:相对于初始的挤压态样品,异步轧制后的组织更均匀细小;随着异速比的增大,再结晶晶粒数量增多,第二相破碎,晶粒和第二相粒子的尺寸减小,组织的均匀化程度提高;样品中主要存在两种第二相,即α-Mn相和MgxZny-Mn-(Ce/La)相;锥面滑移及基面滑移在异步轧制过程中扮演着重要的角色,且基面取向出现了从RD向TD的30°~45°偏转,织构逐渐趋于随机化。强剪切应变的引入、锥面滑移以及基极的偏转对织构的随机化具有显著的影响。

In order to investigate the microstructure and texture evolution of magnesium alloy subjected to differential speed rolling( DSR)with different speed ratios,four different speed ratios were carried out on extruded Mg-3Zn-2( Ce/La)-1Mn alloys. The results indicate that the more uniform and finer microstructure is obtained after DSR compared to the initial extruded specimen. With the increment of SR,the amount of recrystallized grains increases,the size of grains and secondary phase particles are reduced,then the extent of homogenization of microstructure is improved. There are mainly two kinds of second phases in the sample,namely α-Mn phase and MgxZny-Mn-( Ce/La)phase. The < c + a > pyramidal slip and the basal < a > slip both play a major role during DSR. The basal plane orientation is inclined by 30°-45° from the RD toward the TD,and the texture gradually trends to be randomized. The introduction of intensive shear strain,trigger of the < c + a > pyramidal slip and tilting of basal poles have a significant effect on the randomization of the texture.