Phase transformation and structural evolution in a Ti-5at.%Al alloy induced by cold-rolling  

作　　者：Bingqiang Wei Song Ni Yong Liu Xiaozhou Liao Min Song 

机构地区：[1]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China [2]School of Aerospace,Mechanical and Mechatronic Engineering,The University of Sydney,Sydney,NSW 2006,Australia

出　　处：《Journal of Materials Science & Technology》2020年第14期211-223,共13页材料科学技术（英文版）

基　　金：financial supports from National Natural Science Foundation of China(51828102);Australian Research Council(DP190102243)。

摘　　要：The phase transformation,deformation mechanism and their correlation in a cold-rolled Ti-5 at.%Al alloy were investigated.Two types of phase transformations from a hexagonal close-packed(HCP)structure to a face-centered cubic(FCC)structure were observed:the basal-type(B-type)with an orientation relation-ship of<1210HCP//<110FCC and{0001}HCP//{111}FCC,and the prismatic-type(P-type)with an orientation-relationship of<1210HCP//<110FCC and 1010HCP//110FCC.The two types of transformations both accommodate the strain along the<c>axis of the HCP matrix.With the proceeding of deformation,different deformation mechanisms were activated in the FCC and the HCP structures,respectively,which led to a faster grain refinement rate in the FCC structure than in the HCP matrix.Deformation twins with zero macroscopic strain were prevalent in the FCC domains produced by the B-type transformation,while deformation twins with macroscopic strain were normally observed in the FCC domains produced by the P-type transformation.This is in accordance with the lattice mismatches produced during phase transformation.The easy occurrence of deformation twinning in the FCC structure contributed significantly to the grain refinement process.In addition,the interaction between neighboring FCC domains produced by the two types of phase transformations also accelerated the grain refinement process.

关 键 词：Ti-Al alloy Deformation mechanism Phase transformation Grain refinement Deformation twinning 

分 类 号：TG335.12[金属学及工艺—金属压力加工] TG146.23[一般工业技术—材料科学与工程]