半埋藏裂纹金属构件脉冲放电相变应力分析

Analysis on Phase Change Stress after Pulse Current Discharging of Metal Component with Half-embedding Cracks

对含半埋藏裂纹的45钢金属构件进行脉冲放电电磁热止裂强化实验,得出脉冲放电电压与止裂强化效果之间的关系,并对止裂强化前后裂尖形貌及显微硬度进行了对比分析,电磁热止裂强化后,裂尖周围显微硬度得到了大幅度的提高;应用Eshelby等效夹杂原理对脉冲放电止裂后裂纹尖端发生组织转变的相变应力进行了理论计算,结果表明,相变应力为压应力,阻止了裂纹的扩展。研究结果为电磁热止裂技术的实际应用奠定了理论基础。

The relationship between pulse discharge voltage and arrest--strengthening effect was analyzed by pulse discharge experiments of 45 steel metal components with half embedding crack. Ac- cording to the comparisons of the morphology and the micro--hardness near the crack tip before and after the discharge, the micro--hardness near the crack tip after the discharge was improved greatly. The theoretical arithmetic of phase transformation stresses of phase transition region around crack tip after crack arrest strengthening by using the equivalent inclusion principle of Eshelby shows phase transformation stress is compressive stress and it prevents crack propagation, and then a theoretical foundation for the practical applications of electromagnetic thermal arrest techniques is provided.