裂纹倾向严重和搭接区软化是激光表面强化技术面临的两大难题,为此,提出了一种激光点状合金化方法:使预涂在基体表面的合金涂层或由喷嘴送入的合金粉,在激光小孔效应作用下,与基体形成混合熔池,得到合金化点。研究表明,大量规则分布、互不重叠的合金化区及其周围的相变硬化区从总体上降低了疲劳裂纹扩展速率,提高了材料的疲劳寿命。对疲劳裂纹断口的初步分析显示,相变硬化区对阻滞裂纹扩展其到了重要作用。 The severe crack tendency and the softening of overlap area are the two major challenges faced by the laser surface strengthening technology. For this reason, a laser spot-like alloying method is proposed: the alloy coating pre-coated on the surface of the substrate or the alloy fed by the nozzle Powder, under the effect of laser pinhole, form a mixed molten pool with the substrate to obtain the alloyed point. The results show that a large number of regularly distributed and non-overlapping alloying zones and the surrounding transformation hardening zone reduce the fatigue crack growth rate and improve the fatigue life of the material. A preliminary analysis of the fatigue crack fracture shows that the hardening zone in the phase transformation plays an important role in retarding the crack propagation.