SFPB处理的38CrSi钢表面纳米化层微观结构特征

采用超音速轰击技术（Supersonic Fine Particles Bombarding，SFPB）对调质态合金钢38CrSi进行表面纳米化处理，在材料表面制备了纳米结构表层；利用X射线衍射、扫描电镜和透射电镜等分析技术研究了表面纳米层的微观结构特征。结果表明：经SFPB处理后，材料表层发生了严重的塑性变形，表面形成了晶粒尺寸约为15nm的纳米结构层，微观应变约为0．19％；表面纳米层的厚度约为20μm（晶粒尺寸〈100nm），纳米晶粒的尺寸随着距表面距离的增加而增大；在距表面40μm的范围内，高密度的位错墙和位错缠结将晶粒分为了尺寸为200～400nm的胞块结构，分析表明表面纳米化主要是位错运动的结果。

Microstructure of Nanocrystalline Surface Layer of 38CrSi Steel Induced by Supersonic Fine Particles Bombarding

A nanocrystalline surface layer is fabricated on a quenched and tempered 38CrSi Steel by using Supersonic Fine Particles Bombarding （SFPB）. The micro-structural evolution of 38CrSi Steel is characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Experimental evidence show that obvious grains refinement is observed after SFPB treatment and a nano- structure surface layer （grain size 〈 100 nm） of about 20 μm is found. The average grain size in the surface layer is about 15 nm, and the mean microstrain is about 0. 19%. The grain size of the nanocrystalline surface layer varies depending upon distance from the top surface layer. In the region of 40 μm depth, large numbers of cell structures with size of 200 - 400 nm separated by dense dislocation walls and dislocation fangle are formed. Experimental analysis indicates that grain refinement can be attributed to the movement of dislocation.