摘要
采用光学和扫描电子显微镜过对X80大变形管线钢在拉伸和冲击载荷下的变形和断裂过程的实验观察,研究了X80大变形管线钢的变形和断裂行为。结果表明:对于由贝氏体+铁素体组成的双相大变形管线钢,在变形过程中,塑性变形优先在铁素体中进行,随着塑性变形量的增加,双相组织的形态逐渐沿作用力方向呈现明显的位向分布。双相组织中裂纹的产生有3种典型方式,即夹杂物形核、相界面形核以及铁素体或贝氏体基体形核。裂纹的扩展与所受的应力状态有关,在较低应力状态下时,裂纹主要通过铁素体扩展;只有在较高应力状态下,裂纹才穿越贝氏体。在实验观察和分析基础上建立了贝氏体+铁素体大变形管线钢的变形和断裂模型。
The deformation and fracture behaviors of the X80 pipeline steel with excellent deformability were investigated by optical microscope and scan electronic microscope （SEM）. The results indicate that plastic deformation is preferentially occured in ferrite during the deformation process for the experimental steel with dual-phases microstructure of bainite and ferrite. With the increase of the amount of plastic deformation, the morphology of the dual-phases microstructure shows a more obviously orientated distribution along the direction of applied force. Usually, the nucleation of crack in dual-phases microstructure has three typical ways such as inclusion nucleation, phase interface nucleation and nucleation in the matrix of ferrite or bainite. The propagation of cracks is related to the stress state of the steel. When the stress is low, the propagation of crack is mainly occurred in ferrite, and when the stress is high, the crack can propagate through the bainite phase. Finally, the deformation and fracture model of the dual-phases pipeline steel is established based on the studies above.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2014年第2期75-81,共7页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(50874090
51174165)
国家科技支撑计划项目(2011BAE35B01)
西安石油大学'材料科学与工程'陕西省重点学科
关键词
大变形管线钢
双相组织
变形
断裂
pipeline steel with excellent deformability
dual-phase microstructure
deformation
fracture
