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利用高功率Nd:YAG固体激光器对12Crl Mo Vg合金钢进行表面强化实验,利用维氏硬度计测定了激光冲击强化前后12Crl Mo Vg耐热低合金钢试样表面硬度,利用电解抛光去除材料方法测得激光冲击区域试样厚度方向显微硬度。结果发现,激光冲击强化可以明显改善12Crl Mo Vg耐热低合金钢显微硬度,且两次冲击对表面硬度改善效果更好。利用X射线衍射技术测得了试样深度方向残余应力分布,分析了合金钢试样激光冲击强化前后高周疲劳性能,利用扫描电子显微镜观察了疲劳试样断口形貌特征。实验结果表明,激光冲击强化在12Crl Mo Vg耐热低合金钢试样表面引入的残余压应力有效增加12Crl Mo Vg耐热低合金钢试样的高周疲劳寿命,同时,残余压应力的存在可以大幅抑制疲劳裂纹萌生及扩展。
Surface hardening experiments of 12Crl Mo Vg alloy steel were carried out with high power Nd: YAG solid state laser. The hardness of 12Crl Mo Vg heat-resistant low alloy steel before and after laser shock hardening was measured by Vickers hardness tester. In the laser impact area thickness direction of the sample microhardness. The results show that the laser shock can significantly improve the hardness of 12Crl Mo Vg heat-resistant low alloy steel, and the impact of the two shocks to improve the surface hardness better. The distribution of residual stress in the depth direction of the sample was measured by X-ray diffraction. The high-cycle fatigue behavior of the alloyed steel before and after laser shocking was analyzed. The fracture surface morphology of the fatigue specimen was observed by scanning electron microscopy. The experimental results show that the residual compressive stress induced by laser shock on the surface of 12Crl Mo Vg heat-resistant low-alloy steel samples effectively increases the high-cycle fatigue life of the 12Crl Mo Vg heat-resistant low alloy steel samples, meanwhile, the residual compressive stress can exist Greatly suppress fatigue crack initiation and propagation.