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.

In this study, we developed a cylindrical electrodeposited diamond mesh grinding wheel for machining large-diameter holes (80 and 160 mm in diameter) in CFRP plates. This tool differs from a general hole saw in that it can also be used on the sides, and can even finish the hole wall surface by taking advantage of its high chip discharge performance due to the wire mesh base metal. When using the side face of this wheel, the main machining is performed at points of wire crossing where the radial protrusion is large, but a smooth surface can be obtained by tracing the hole contour while oscillating the tool up and down. After repeated finishing operations without increasing the depth of cut, the difference from the target dimension becomes as small as approximately 0.02 mm, indicating that the surface roughness meets the standard values for aircraft parts.