2025 Volume 69 Issue 1 Pages 30-34
To obtain hybrid surface modification capable of achieving both high compressive residual stress and coating with Cu or Sn on the peened surface, media with high hardness containing a Cu or Sn phase were used for micro-shot peening. FeCrBCu and FeCrBSn alloy powders with Vickers hardness exceeding 1200 HV were manufactured by gas atomization, followed by sieving for particle diameter under 45μm for shot peening media. The peened workpieces were SUJ-2 with quenching and tempering. High compressive residual stress of -1500 MPa and transfer of Cu and Sn onto the peened surface were observed using FeCrBCu and FeCrBSn media, respectively. Cu and Sn were detected at >10 mass% on the surface by EDX analysis. As the solubility limits of Cu and Sn to α´Fe are both <1 mass% at room temperature, at least some of the Cu and Sn on the surface was considered to have formed a solid solution to supersaturation with α´Fe. These results indicated that hybrid surface modification was successfully achieved.
