Effect of aging treatment on the microstructures and mechanical properties evolution of 25Cr-20Ni austenitic stainless steel weldments with different Nb contents

作     者：Xu Zhang Dianzhong Li Yiyi Li Shanping Lu 

作者机构：Key Laboratory of Nuclear Materials and Safety AssessmentInstitute of Metal ResearchChinese Academy of Sciences School of Materials Science and EngineeringUniversity of Science and Technology of China Shenyang National Laboratory for Materials ScienceInstitute of Metal ResearchChinese Academy of Sciences 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2019年第35卷第4期

页      面：520-529页

核心收录：

学科分类：080503[工学-材料加工工程] 0806[工学-冶金工程] 0817[工学-化学工程与技术] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0802[工学-机械工程] 0702[理学-物理学] 0801[工学-力学（可授工学、理学学位）] 080201[工学-机械制造及其自动化] 

基　　金：supported by the research and development of nuclear materials and service safety assurance technology (Grant No.ZDRW-CN-2017-1) the National Natural Science Foundation of China (NSFC) (Grant No.51474203) 

主　　题：25Cr-20Ni steel Weld metal Nb Aging treatment α-Cr phase Mechanical property 

摘      要：The microstructure evolutions and the mechanical properties of the 25Cr-20Ni austenitic stainless steel weld metals with different Nb contents were investigated during the long term aging treatment at 700~?C.M_(23)C_6,Nb(C,N),α-Cr phase and Nb-nitride phase(Z phase)were observed in the microstructures of the aged weld *** results showed that theα-Cr phase precipitated in the interdendritic regions of the weld metals after being exposed to~ 700?C for 500 h and the element Nb accelerated the precipitation of theα-Cr phase *** density of theα-Cr phase decreased with the increase of the distance away from the primary Nb(C,N).Additionally,theα-Cr phase showed a crystallographic relationship with the austenitic matrix,■.It was observed that the Z phase precipitated in the periphery of the Nb(C,N)and may replace the Nb(C,N)after long term exposure to high *** transformation of the Nb(C,N)into Z phase suggested that the Z phase had a higher stability than the Nb(C,N)par^ticles at 700?C for long term *** tensile strength of the Nb-bearing weld metal showed a continuous decrease at the initial stage of the aging treatment and then went up slightly with the prolonged aging ***,the elongations and the impact energies of the weld metals decreased monotonously with the increase of the aging time.