Synergistic evolution mechanism of deformation and surface integrity for aeroengine blades under laser and mechanical shot peening

Laser and mechanical shot peening (LSP-SP) is an emerging surface modification technology for aeroengine blades. However, while improving the surface integrity of the blades, LSP-SP can also introduce undesirable deformation. In this study, the LSP-SP process was discretized to investigate the deformation of blade cross-sections at various processing stages. Residual stress measurements and microstructural characterizations were conducted to establish the synergistic evolution between deformation and surface integrity. Through stress-strain analysis of a representative thin-walled structure, a plasticity-induced stress theory is proposed to elucidate the synergistic mechanism between residual stress evolution and deformation. Specifically, plastic strain induces a plasticity-driven stress field that initiates elastic deformation, leading to the generation of elasticity-induced stress. The interaction between these stress causes reconstruction of the residual stress field, with deformation ceasing upon achieving internal stress equilibrium. Building on this mechanism, a deformation prediction model for LSP-SP-treated blades was developed, achieving a prediction accuracy exceeding 90 %. This work not only provides forward validation of the proposed theoretical framework but also provides theoretical and methodological references for the deformation-resistant surface integrity design of the blades.