Study on deformation mechanism of Ti-2Al-2.5Zr alloy tube in the flattening test  

作　　者：Shengkun Wang Gang Jin Yuntao Wu Xiao Liu Gang Chen 

机构地区：[1]School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China [2]Nuclear and Radiation Safety Center,MEE,54#,Beijing 100082,China [3]School of Chemical Engineering,Sichuan University,Sichuan 610065,China [4]Nuclear Power Institute of China,Chengdu,Sichuan 610015,China

出　　处：《Journal of Materials Science & Technology》2021年第31期108-120,共13页材料科学技术（英文版）

基　　金：financial support from the National Natural Science Foundation of China(Nos.51875398 and 51471116);the Sichuan Science and Technology Program(2019ZDZX0001);the Project of Nuclear Power Technology Innovation Center of Science Technology and Industry for National Defense(HDLCXZX-2019-ZH-26);the Science and Technology on Reactor System Design Technology Laboratory,Nuclear Power Institute of China。

摘　　要：The flattening test,using one pair paralleled plates to flatten tube structure radially,is generally employed to examine the ductility of tube used in once through steam generator(OTSG).This study focuses on the stress condition and deformation mechanism analysis on the concentrated stress regions of Ti-2 Al-2.5 Zr alloy tube during the flattening test.Firstly,the finite element analysis was performed using the commercial software ABAQUS to determine the stress condition.Secondly,the Electron BackScattered Diffraction(EBSD)was implemented to observe the microstructure evolution of Ti-2 Al-2.5 Zr alloy.Finally,Schmid law was employed to analyze the activated deformation mechanism under condition of the complex stress.It was found that the condition of the complex stress in stress concentration regions,including tension and compression regions,can be simplified into two directional stresses condition.In grains whose c-axis is nearly towards TD and ND,the strain is mainly accommodated by prismatic slip,whereas in grains whose c-axis deviates about 45°from ND to TD mainly by basal slip.The{10-12}extensive twin and corresponding parent grain orientation mainly relied on the stress condition.Additionally,the intergranular twin pairs connected at common grain boundaries(GBs)with high strain compatibility were found at low angle GBs,which were activated under a combination of macro stress and strain compatibility effect.

关 键 词：Ti-2Al-2.5Zr alloy tube Flattening test EBSD Stress condition Deformation mechanism Schmid factor Twin pairs Strain compatibility effect 

分 类 号：TG146.23[一般工业技术—材料科学与工程]