Fig. 1. Size of fretting wear samples and laser shock path. (a) Size of fatigue sample; (b) size of fretting pad; (c) multi-spot overlapping laser shock path

Fig. 2. Schematic illustration of fretting wear equipment. (a) Macroscopic image; (b) fretting contact

Fig. 3. Schematic illustrations of multi-spot overlapping laser shock micro-dimples. (a) Schematic illustration of multi-spot overlapping; (b) imaginary unit cell and the texturing dimples

Fig. 4. Morphology, microhardness, and residual stress of laser shock textured dimples at different overlapping rates. (a)‒(c) Morphology of laser shock textured dimples; (d) surface microhardness of laser shock dimple-textured samples and DLC coated samples; (e) surface residual stress of LSP-30% sample and LSP-30% sample with DLC coating (LSP-30%&DLC sample)

Fig. 5. Indentation morphology of the samples with DLC coating. (a) As-received sample with DLC coating; (b) LSP-20% sample with DLC coating; (c) LSP-30% sample with DLC coating; (d) LSP-40% sample with DLC coating

Fig. 6. Fretting wear SEM morphology, EDS maps and 2D wear profiles of each coated sample. (a)(a1)(a2)(a3)(a4) As-received sample with DLC coating; (b)(b1)(b2)(b3)(b4) LSP-20% sample with DLC coating; (c)(c1)(c2)(c3)(c4) LSP-30% sample with DLC coating; (d)(d1)(d2)(d3)(d4) LSP-40% sample with DLC coating

Fig. 7. Microscopic wear morphology of as-received sample with DLC coating. (a) Region a1 in Fig. 6(a); (b) enlarged image of region b

Fig. 8. Microscopic fretting wear morphology of the coating on the surface of LSP-30% and LSP-40% samples with DLC coating. (a) Marked c1 region in Fig. 6(c); (a1) enlarged image of region a1; (b) marked d1 region in Fig. 6(d); (b1) enlarged image of region b1