Effect of weld microstructure on brittle fracture initiation in the thermallyaged boiling water reactor pressure vessel head weld metal

作     者：Noora Hytönen Zai-qing Que Pentti Arffman Jari Lydman Pekka Nevasmaa Ulla Ehrnstén Pål Efsing Noora Hytönen;Zai-qing Que;Pentti Arffman;Jari Lydman;Pekka Nevasmaa;Ulla Ehrnstén;Pål Efsing

作者机构：Nuclear Reactor MaterialsVTT Technical Research Centre of Finland Ltd.Kivimiehentie 3P.O.Box 1000FI-02044 VTTFinland Department of Solid MechanicsRoyal Institute of Technology(KTH)SE-10044 StockholmSweden 

出 版 物：《International Journal of Minerals,Metallurgy and Materials》 (矿物冶金与材料学报（英文版）)

年 卷 期：2021年第28卷第5期

页      面：867-876页

核心收录：

学科分类：080503[工学-材料加工工程] 080802[工学-电力系统及其自动化] 0808[工学-电气工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：the SAFIR2022 BRUTE project (Barseback RPV material used for true evaluation of embrittlement) for funding the study 

主　　题：reactor pressure vessel brittle fracture weld microstructure thermal aging 

摘      要：Effects of the weld microstructure and inclusions on brittle fracture initiation are investigated in a thermally aged ferritic high-nickel weld of a reactor pressure vessel head from a decommissioned nuclear power ***-welded and reheated regions mainly consist of acicular and polygonal ferrite,*** examination of Charpy V-notch impact toughness specimens reveals large inclusions(0.5-2.5μm)at the brittle fracture primary initiation *** impact energies were measured for the specimens in which brittle fracture was initiated from a small inclusion or an inclusion away from the *** density,geometry,and chemical composition of the primary initiation inclusions were investigated.A brittle fracture crack initiates as a microcrack either within the multiphase oxide inclusions or from the debonded interfaces between the uncracked inclusions and weld metal *** fracture sites can be determined in all the specimens tested in the lower part of the transition curve at and below the 41-J reference impact toughness energy but not above the mentioned value because of the changes in the fracture mechanism and resulting changes in the fracture appearance.