铁磁性材料拉伸损伤过程的磁学特性

Magnetic properties in tensile damage process of ferromagnetic materials

采取分级加载拉伸断裂和重复加载拉伸断裂两种加载方式,对不同初始磁场强度的板状试样进行了单轴拉伸试验,采用磁学信号特征量研究了中碳钢拉伸损伤过程。通过对试样变形过程磁学信号特征的分析,确定了中碳钢不同拉伸损伤阶段的磁学特性:弹性阶段的磁场强度和初始磁场分布规律一致,在材料由弹性损伤到塑性损伤过渡阶段,磁场强度均值及其标准差出现拐点;在颈缩阶段,磁场强度及其梯度信号明显增大,由此能够判断中碳钢由拉伸弹性损伤状态向屈服损伤状态的转变,以及材料断裂情况的出现,从而对工程中铁磁性构件的破坏性事故做出预警。

This paper is devote to uniaxial tensile tests of plate samples with different initial field strength using graded loading and repeated loading and study on the tensile damage process magnetic of medium carbon steel using the characteristic value of magnetic signal. The analysis of the magnetic signal characteristics of the deformation process leads to the determination of the magnetic properties of medium carbon steel at different tensile damage stages. Among the magnetic properties are the consistency between the distribution rule of magnetic field strength and the initial magnetic field strength at the elastic stage, the occurrence of inflection points on the mean and standard deviation curves of magnetic field strength during the transition from elastic damage to the plastic, and an obvious increase in magnetic field strength and its gradient signal at the necking stage, from which arises the transition from stretching elas- tic damage to yield damage and the occurrence of material fracture, thus giving a warning on the destructive accidents of ferromagnetic components in engineering.