Abstract
A nano-structured alloying layer was fabricated by the addition of 304 stainless steel powder to the surface of a low carbon steel (LCS) plate by surface mechanical attrition treatment (SMAT). The coverage of the stainless steel layer was 93 % after SMAT for 60 min. The thickness of the surface layer was approximately 35 μm. The average grain size in the top layer was in the range of 55–65 nm with random crystallographic orientation, and the grain size increased with increasing depth from the treated surface. Both the surface hardness and wear resistance of the sample that underwent a surface nano-alloying treatment (SNAT) increased compared with those of the LCS sample. Additionally, the wear resistance increased for the nanocrystalline (nc) surface layer. Nanoindentation measurements indicated that micro-hardness in the nc surface layer was approximately 645 HV, which was three times as high as that of the LCS matrix.

Key words
surface nano-alloying treatment (SNAT), surface mechanical attrition treatment (SMAT), microstructure, 304 stainless steel layer, micro-hardness

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