Deformation and cracking behaviors of proton-irradiated 308L stainless steel weld metal strained in simulated PWR primary water  

作　　者：Xiaodong Lin Qunjia Peng En-Hou Han Wei Ke 

机构地区：[1]Institute of Materials,Shanghai University,Shanghai 200072,China [2]Suzhou Nuclear Power Research Institute,Suzhou 215004,China [3]Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China

出　　处：《Journal of Materials Science & Technology》2022年第25期36-52,共17页材料科学技术（英文版）

基　　金：financially supported by the Jiangsu Natural Science Foundation (No. BK20191178);the National Natural Science Foundation of China (No. 52071018);the China Postdoctoral Science Foundation (No. 2021M692018)。

摘　　要：The proton-irradiated 308L stainless steel weld metal was strained by using constant extension rate tensile testing in simulated PWR primary water, and its deformation microstructures and irradiation assisted stress corrosion cracking(IASCC) behavior were investigated. The results suggest that the irradiation significantly increases the SCC susceptibility of 308L weld metal and causes various deformation microstructures including lathy faulted planes, dislocation channels and deformation twins in austenite and atomic plane rotation in δ-ferrite. The propagation of intergranular IASCC cracks is closely related to the location of the crack tip. For the crack tip in the specimen matrix interior, localized deformation is likely the key factor responsible for the crack growth. For the crack tip close to the specimen surface, however, localized corrosion along the grain boundary rather than the localized deformation appears to dominate the crack propagation. Unlike the intergranular cracks, the IASCC cracks along the δ-ferrite/austenite phase boundary can initiate either by crack initiation at the phase boundary or by crack propagation from the grain boundary. In both cases, the cracked phase boundaries contain a large number of carbides and are severely corroded, but no deformation microstructures are observed, which implies that the localized corrosion may play an important role in the IASCC along the phase boundary. In addition, δ-ferrite can retard the IASCC crack propagation along the grain boundary, which is probably related to the reduction of localized deformation by δ-ferrite.

关 键 词：Stainless steel weld metal Proton irradiation Deformation microstructures Irradiation assisted stress corrosion cracking Grain and phase boundaries 

分 类 号：TG441.7[金属学及工艺—焊接]