Review of short-to-ultrashort pulsed laser shock peening research: mechanisms, processes, and applications

Laser shock peening (LSP) is an advanced surface strengthening technique crucial for enhancing the performance of critical components operating in extreme service environments. By generating gradient residual compressive stress and refining the microstructure via the interaction between the laser and metallic materials, LSP achieves multiscale modulation of the surface properties of metal components and considerably improves the fatigue, wear, and corrosion resistance of the material under demanding conditions. Owing to its noncontact surface modification process and properties, LSP has garnered considerable interest across fields such as aerospace, rail transit, biomedicine, and the nuclear industry. The pulse duration of the laser used in LSP considerably influences its interaction with metallic materials. Ultrashort-pulsed LSP exhibits extreme nonlinear, nonequilibrium, and multiscale time/space properties during its interaction with metallic materials, distinguishing it from short-pulsed LSP. However, existing reviews have predominantly analyzed LSP based on various factors, equipment, single performance, and applications. The pulse duration, which inevitably influences the application of LSP, has not been investigated yet. This review analyzes about 180 short-pulsed LSP and approximately 100 ultrashort-pulsed LSP papers published between 1963 and 2025 and focuses on the laser pulse duration to elucidate the existing status and prospective application value of short- and ultrashort-pulsed LSP from the viewpoints of mechanisms, processes, and applications. The associated challenges and prospects are examined and summarized using strengthening mechanisms, high-fidelity prediction models, process coupling innovations, and intelligent and efficient strengthening equipment. This work offers valuable insights for advancing laser manufacturing processes towards meeting the rigorous demands of extreme applications.