利用高速微粒轰击技术在45钢表面制备了纳米晶,利用透射电镜(TEM)和X射线衍射(XRD)等分析技术对距表面不同深度的微观结构进行分析,研究铁素体相晶粒细化过程。结果显示:随着距表面距离的减小结构尺寸逐渐减小,在最表面形成了纳米晶层,平均晶粒尺寸约为15 nm。通过不同尺寸位错胞的逐步形成,以及位错墙不断向晶界演化,晶粒被细化为细小的纳米晶。 The nanocrystalline was prepared on the surface of 45 steel by high-speed particle bombardment. The microstructure of the 45 steel was analyzed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The microstructure of the ferrite phase was studied. process. The results show that with the decrease of the distance from the surface, the size of the nanostructured nanocrystalline layer decreases with the increase of the surface area. The average grain size is about 15 nm. Through the gradual formation of dislocation cells of different sizes and the continuous dislocation wall to the grain boundary, the grains are refined into fine nanocrystals.