STUDY ON DYNAMIC STRAIN AGING AND LOW-CYCLE FATIGUE OF STAINLESS STEEL IN ULTRA-SUPERCRITICAL UNIT
Dynamic strain aging(DSA)and low-cycle fatigue(LCF)behavior of TP347H stainless steel in ultra-supercritical unit were investigated at 550-650℃.All the LCF tests were carried out under a fully-reversed,total axial strain control mode at the total strain amplitude from ±0.2%to ±1.0%.The effects of DSA in cyclic stress response,microstructure evolution and fatigue fracture surfaces and fatigue life were investigated in detail.The results show that DSA occurs during tensile,which is manifested as serrated flow in tensile stress-strain curves.The apparent activation energy for appearing of serrations in tensile stress-strain curves was 270 kJ/mol.Pipe diffusion of substitutional solutes such as Cr and Nb along the dislocation core,and strong interactions between segregated solutes and dislocations are considered as the mechanism of DSA.DSA partly restricts dislocation cross–slip,and dislocation cross–slip and planar–slip happen simultaneously during LCF.A lot of planar structures form,which is due to dislocation gliding on the special plane.This localized deformation structures result in many crack initiation sites.Meanwhile,DSA hardening increases cyclic stress response,accelerating crack propagation,which reduces high temperature strain fatigue life of steel.
Ultra-supercritical unit Austenitic stainless steel Stain fatigue Dynamic strain aging
Zhou Hongwei He Yizhu Lv Jizu Rao Sixian
School of Materials Science and Engineering,Anhui University of Technology 59 Hudong Rd.Maanshan,243 School of Materials Science and Engineering,Anhui University of Technology 59 Hudong Rd.Maanshan,243 Huadian Heavy Industries Co.,Ltd.,Huadian industrial park in Fengtai Automobile Museum Rd.Beijing,10 School of Materials Science and Engineering,Anhui University of Technology 59 Hudong Rd.Maanshan,243
国际会议
Energy Materials 2014(第一届能源材料国际会议)
西安
英文
299-306
2014-11-04（万方平台首次上网日期，不代表论文的发表时间）