Early elastoplastic stability of LSPwC micro-dimpled AISI 9310 steel under non-uniform lubrication-pressure loading

Surface micro-textures adjust friction, bearing capacity and surface deformation, yet their stability relies on machining-affected subsurface material states. Laser shock peening without coating (LSPwC) fabricates micro-dimples on AISI 9310 steel with hardness gradients and residual stresses. Uneven lubrication pressure triggers localized plasticity around dimples prior to obvious pit depth reduction, decoupling plastic evolution and geometric degradation. This study establishes a cross-scale elastoplastic model mapping non-uniform pressure from macro fluid-structure interaction lubrication simulations to a micro 3 × 3 dimple array constrained by tested hardness and residual stress data. Hardness-residual stress decoupling and pressure-template overload scanning isolate their individual influences. Plastic strain emerges and expands before notable pit-depth loss. The tensile near-surface portion of reconstructed residual-stress field promotes earlier local yielding, whereas the hardness gradient markedly limits subsequent plastic spreading. Tribological data and post-test morphology provide a consistency check, offering a tool to assess contact stability of LSPwC textures under uneven lubrication overloads.