Residual Stress Improvement Mechanism on Metal Material by Underwater Laser Irradiation.
Residual Stress Improvement Mechanism on Metal Material by Underwater Laser Irradiation.
复制标题
水下激光辐照对金属材料残余应力的改善机制。
DOI：
10.3327/jaesj.42.567
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
S. Shima
中科院分区：
文献类型：
--
作者：
Y. Sano;Masaki Yoda;N. Mukai;M. Obata;M. Kanno;S. Shima
水下脉冲激光辐照构件表面残余应力改善技术是防止核反应堆堆芯构件应力腐蚀开裂（SCC）的一种方法。为了优化激光辐照条件的基础上，一个完整的理解的机制，冲击波的传播引起的激光照射的脉冲和辐照材料的动态响应进行了分析，通过与时间相关的弹塑性计算与有限元程序。将计算结果与用能量为200mJ的激光脉冲聚焦到直径为0.8mm的20%冷加工304型奥氏体不锈钢水浸试件上模拟中子辐照硬化的实验测量结果进行了比较。在冲击波以足够的振幅通过以引起永久应变之后，几乎等于被处理材料的屈服应力的残余压应力保留在材料表面上。激光脉冲的多次照射将应力改善深度扩展到约1mm，这将是与冲击波的三维弥散效应相对应的极限。
Residual stress improvement technology for component surface by underwater pulsed laser irradiation has been developed as a method of preventing stress corrosion cracking (SCC) of core components in nuclear reactors. In order to optimize the laser irradiation conditions based on a complete understanding of the mechanism, the propagation of a shock wave induced by the impulse of laser irradiation and the dynamic response of the irradiated material were analyzed through time-dependent elasto-plastic calculations with a finite element program. The calculated results are compared with the measured results obtained by experiments in which laser pulses with an energy of 200mJ are focused to a diameter of 0.8mm on a water-immersed test piece of 20% cold-worked Type 304 austenitic stainless steel to simulate neutron irradiation hardening. A residual compressive stress, which is nearly equivalent to the yield stress of the processed material, remains on the material surface after passage of the shock wave with enough amplitude to induce a permanent strain. Multiple irradiation of laser pulses extends the stress-improved depth to about 1mm, which would be the limit corresponding to the three-dimensional dispersion effect of the shock wave.