纯Mo棒在镦粗过程中的织构和组织对其横向塑性的影响

Effects of texture and microstructure on transverse ductility of pure molybdenum bars in upset process

对锻造纯Mo棒进行不同变形量的镦粗加工,观察其在此过程中的室温横向弯曲性能和织构演变。结果表明:锻造变形85%的纯Mo棒的横向弯曲伸长率仅为0.5%,经镦粗变形其横向塑性得到提高;镦粗变形50%和85%后,伸长率分别达到1.5%和5.0%,其原因是在纯Mo棒中形成的纵向伸长的纤维组织被横向扭曲,且晶粒间相互穿插,这种组织由<011>织构的组织演变而来;锻造Mo棒中形成<011>纤维织构,这种织构对Mo棒的横向塑性不利,经镦粗变形,<011>纤维织构转变为<001>和<111>纤维织构;锻态Mo棒的断裂方式为沿晶断裂,镦粗变形后,断裂方式主要为穿晶断裂;断口还发现有"分层韧化"现象出现。

The transverse elongations and textures of pure molybdenum bars manufactured by upset with different amounts of deformation were investigated at room temperature.The results show that the transverse elongation of the forged Mo bars with 85% deformation is 0.5%,which is greatly improved by the upset process.By upset with 50% and 85% deformations,the transverse elongations of the bars are only 1.5% and 5.0%,respectively,because the fiber structures in the longitudinal direction are distorted along with the transverse direction and interpenetrate each other,and these structures are developed from 011 fiber;which has a bad effect on the transverse ductility of the forged Mo bars.After the upset deformation,the fiber texture of 011 changes to 001 and 111.The fracture mode changes from intergranular to a transgranular and shows a ductile laminate fracture mechanism.