DOI number:10.1016/j.ijfatigue.2023.108113
Affiliation of Author(s):南京工程学院
Teaching and Research Group:0
Journal:International Journal of Fatigue
Place of Publication:荷兰
Funded by:江苏省自然科学基金，2020年“双创计划”特别人才引进，江苏省先进结构材料与应用技术重点实验室开放项目，南京工程学院人才引进研究基金
Key Words:fatigue crack propagation, dendritic structure, ERNiCrMo-3 weld metal, element segregation,local plastic deformation, post-weld heat treatment.
Abstract:The effect of dendritic structure and secondary phases on the fatigue crack propagation mechanism of ERNiCrMo-3 weld metal was investigated. Element segregation in the weld metal induced severe lattice distortion in the interdendritic region, creating substantial variations in mechanical properties between the dendrite core and interdendritic region. This disparity resulted in an unstable crack propagation rate. The limited plastic deformation capacity of the interdendritic region caused a contraction in the local plastic deformation zone at the crack tip, increasing stress concentration and accelerating crack propagation. The fatigue crack in the interdendritic regions exhibited a rate of approximately 2.6 μm/cycle, surpassing the 1.5 μm/cycle observed in the dendrite cores. Meanwhile, element segregation promoted the precipitation of numerous Laves phases in the interdendritic regions. With increasing stress, micro-voids formed by broken Laves phases served as rapid channels for crack propagation. Post-weld heat treatment weakened the non-uniformity of the microstructure. The fatigue crack propagated at a rate of about 1.2 μm/cycle. Furthermore, the dissolution of Laves phases and the precipitation of γ″ enhanced the fatigue performance of the weld metal. Under equivalent stress levels, the fatigue life of post-weld heat-treated weld metal increased by approximately 1.2 times compared to that of as-welded metal.
Note:0
Indexed by:研究论文
Document Code:108113
Volume:180
ISSN No.:1879-3452
Translation or Not:no
Date of Publication:2024-01-01