The mechanism of flow softening in subtransus hot working of two-phase titanium alloy with equiaxed structure  

作　　者：Xiaoguang Fan He Yang Pengfei Gao 

机构地区：[1]State Key Laboratory of Solidification Processing,School of Materials Science and Engineering,Northwestern Polytechnical University

出　　处：《Chinese Science Bulletin》2014年第23期2859-2867,共9页

基　　金：supported by the National Natural Science Foundation of China (50935007,51205317);the National Basic Research Program of China (2010CB731701);111 Project (B08040)

摘　　要：Understanding the mechanism of high temperature deformation is important for controlling the forming quality of the titanium alloy forgings.In the present work,the flow softening mechanism in subtransus deformation of titanium alloys with equiaxed structure was investigated by interrupted isothermal compression tests.The results show that limited strain hardening followed by continuous flow softening occurs in high temperature deformation of a twophase TA15 titanium alloy.The flow softening can not be rationalized by dynamic recrystallization.Instead,the increase of mobile dislocations during deformation is an important reason for flow softening.The grain boundaries(including the a-b interfaces)act as an important source for the generation of mobile dislocations.The continuous flow softening results from the significant deformation heterogeneity in subtransus working.Understanding the mechanism of high temperature deformation is important for controlling the forming quality of the titanium alloy forgings. In the present work, the flow softening mechanism in subtransus deformation of titanium alloys with equiaxed structure was investigated by interrupted isothermal compression tests. The results show that limited strain hardening followed by continuous flow softening occurs in high temperature deformation of a twophase TA15 titanium alloy. The flow softening can not be rationalized by dynamic recrystallization. Instead, the increase of mobile dislocations during deformation is an important reason for flow softening. The grain boundaries （including the α-β interfaces） act as an important source for the generation of mobile dislocations. The continuous flow softening results from the significant deformation heterogeneity in subtransus working.

关 键 词：连续流动 两相钛合金 软化 机制 结构 热加工 TA15钛合金 高温变形 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TU991.21[金属学及工艺—金属材料]