关键词: 纳米材料, 38CrMoAl钢, 铁, 渗氮, 表面机械研磨

Abstract:

The microstructure of the surface layer on a pure iron and a 38CrMoAl steel samples was refined into the nanometer scale by means of the surface mechanical attrition treatment ( SMAT) that generates repetitive severe plastic deformation in the surface layer. The subsequent nitriding kinet ics of the SMAT samples with a nanostructured surface layer is greatly enhanced so that the nitriding temperatures can be reduced to 300 e for iron and about 400 e for 38CrMoAl steel, respectively, which are much lower than the convent ional nitriding temperatures ( above 500 e ). The novel nitriding process not only facilitates reduction of torsion of the treated samples, but also provides a new approach for select ive surface reactions of solids.

Key words: nanocrystalline materials, 38CrMoAl steel, iron, nitriding, surface mechanical attrition treatment