摘要
采用三点弯曲试样加载过程声发射监测实验,结合断口SEM观察及X射线能谱分析,考察了30CrMnSi合金钢延性断裂的整个物理过程。结果表明:30CrMnSi钢的断裂过程从宏观上可以分为裂尖塑性变形、裂纹亚临界扩展和裂纹失稳扩展三个阶段。其机理如下:裂尖塑性变形过程是位错的滑移、堆积而引起的孔洞形核和长大;裂纹亚临界扩展过程为韧窝之间的连通;裂纹失稳扩展过程则是晶体的大规模解理。随着延性断裂过程的进行,各阶段均呈现脆性断裂特征逐渐增强的趋势,表现为韧窝尺寸的减小和声发射高幅值信号的增加。断裂过程各阶段声发射信号特征明显,声发射技术是监测30CrMnSi钢断裂损伤发展的有效手段。
The whole physics process of ductile fracture in 30CrMnSi steel was investigated by the experiment of three-point bending specimen,which was monitored by acoustic emission system and the analysis of fracture by SEM and X-ray spectrometer.The results indicate that the whole process of the fracture includes there stages： the plastic deformation of crack tip,the crack pre-critical propagation and the crack critical propagation.The process of plastic deformation of crack tip is the formation and growth of cavity.The essential of crack pre-critical propagation is the connection of the dimples and the crack critical propagation is attributed to large-scale cleavage.There is a tendency to be more brittle during ductile fracture propagation for all stages.It is testified that acoustic emission technology is an efficient means to monitor the damage propagation for the high strength steel.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2011年第1期17-22,共6页
Journal of Materials Engineering
关键词
高强度合金钢
声发射
断裂机理
断裂韧度
high strength steel
acoustic emission
fracture mechanism
fracture toughness
