Fusion boundary evolution, precipitation behaviour, and interaction with dislocations in an Fe–22Cr–15Ni steel weldment during long-term creep  

作　　者：Yu Zhang Hongyang Jing Lianyong Xu Yongdian Han Lei Zhao Xishan Xie Zhengxin Tang 

机构地区：[1]School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China [2]Tianjin Key Laboratory of Advanced Joining Technology,Tianjin 300350,China [3]State Key Laboratory of Engines,Tianjin University,Tianjin 300350,China [4]School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《Progress in Natural Science:Materials International》2019年第1期41-49,I0003,共10页自然科学进展·国际材料（英文版）

基　　金：financial support provided by the Project of the National Natural Science Foundation of China (Grant number 51475326);the Demonstration Project of National Marine Economic Innovation (BHSF2017-22)

摘　　要：A tungsten inert gas welded joint between a novel heat-resistant austenitic steel and ERNiCrCoMo-1 weld metal was investigated before and after creep in this study. The evolution of the microstructures in the base and weld metals was discussed based on the electron back-scatter diffraction(EBSD) and transmission electron microscopy(TEM) analyses. The preferred orientations of the fusion boundary after creep revealed the influence of the applied stress on creep deformation mechanism. A cooperative nucleation process of M23C6 carbides in the base metal was proposed. The finely distributed Cu-rich phase was cut off by the dislocations during creep, leading to increased mean size and reduced amount of the nano-Cu phase. A modified triple-precipitate hardening model was constructed based on TEM observations of the interactions between the particles and the dislocations in the base metal after creep at 200 MPa. The evolution of a μ phase in the weld metal involved epitaxial growth and dissolving into the matrix.A tungsten inert gas welded joint between a novel heat-resistant austenitic steel and ERNiCrCoMo-1 weld metal was investigated before and after creep in this study. The evolution of the microstructures in the base and weld metals was discussed based on the electron back-scatter diffraction（EBSD） and transmission electron microscopy（TEM） analyses. The preferred orientations of the fusion boundary after creep revealed the influence of the applied stress on creep deformation mechanism. A cooperative nucleation process of M23C6 carbides in the base metal was proposed. The finely distributed Cu-rich phase was cut off by the dislocations during creep, leading to increased mean size and reduced amount of the nano-Cu phase. A modified triple-precipitate hardening model was constructed based on TEM observations of the interactions between the particles and the dislocations in the base metal after creep at 200 MPa. The evolution of a μ phase in the weld metal involved epitaxial growth and dissolving into the matrix.

关 键 词：HEAT-RESISTANT STEEL WELDMENT CREEP EBSD NUCLEATION mechanism Nano Cu-rich phase 

分 类 号：TG1[金属学及工艺—金属学]