中文摘要：

为提高38CrMoAl钢渗氮层质量和耐磨性能，提出了激光冲击处理增强渗氮的组合方法。利用球磨实验分析了不同激光冲击次数下渗氮的耐磨性能，采用SEM和XRD研究了激光不同冲击次数对38CrMoAl渗氮的微观组织和相成分的影响。结果表明随着冲击次数的增加，试样的比磨损率先降低后增加。从微观组织和相分析两个方面讨论了冲击次数对渗氮耐磨性能的影响机理激光冲击强化可促进渗氮的过程。在没有新相形成的条件下，随着激光冲击次数的增加，试样的表层形成的氮化物颗粒增大、数量增多，固溶强化和第二相强化作用增强，从而提高其耐磨性能。但当冲击次数继续增加，大量的氮化物沿晶界成网状分布时，就会降低38CrMoAl钢的耐磨性能。

英文摘要：

In order to improve the nitridation layer＇s quality and wear performance of 38CrMOAl steel, we put forward a combined method of laser shock processing and nitridation. Through ball milling experiments, we measured the wear performances of 38CrMOAl steel samples, which were nitridated after processing by different times of laser shocks. We also examined the microstructure and phase composition of the samples using SEM and XRD. The result shows that, with increasing times of laser shocks, the wear rates of the samples decrease firstly and increase afterwards. Moreover, we discussed the mechanism of improving wear resistance by laser shock treatment from two perspectives, namely, the microstructure and phase composition of the nitridated surface. It is concluded that laser shock processing can promote nitridation. When no new phase is formed in the nitridation layer, with increasing times of laser shocks, the sizes and number of the nitride particles in the surface increases, hence, the second diphase strengthening and the solution streng-thening effects are enhanced, as well as the wear resistance is improved. However, when the laser shocks are more than a certain value, lots ofnitride particles along the grain boundary will distribute with reticulation, thus reduce the wear resistance.