Enhancement of the Properties of Different Metal Materials by Femtosecond Laser Shock Peening: A review

Recent advancements in alloy engineering have unlocked unprecedented performance in titanium, aluminum, and nickel systems through innovative processing and microstructural control. Titanium alloys, such as FsLSP-treated Ti6Al4V, achieve multifunctional enhancements via femtosecond laser shock peening (FsLSP), which introduces compressive residual stresses (200–800 MPa) and ultrafine/nanocrystalline grains (50–500 nm), elevating high-cycle fatigue life (3.7–7× improvement), hardness (~28% increase), and wear resistance (30–50% reduction). Simultaneously, laser-induced TiO 2 passivation layers suppress corrosion currents to 1.45×10 –9 A/cm 2 , while hierarchical surface texturing enhances hydrophobicity (contact angle ~111°), positioning these alloys for aerospace and biomedical applications. Aluminum alloys leverage precipitation hardening (e.g., η-phase MgZn 2 in AA7075, yield strength >500 MPa) and severe plastic deformation (SPD) techniques like ECAP to refine grains to <1 μm, boosting AA6061’s ultimate tensile strength to 600 MPa with retained ductility. Surface anodization and LSP mitigate chloride-induced pitting (corrosion current <0.1 μA/cm 2 ), while Al-Li variants (AA2099) reduce density by 8–10%, enhancing aerospace efficiency. Recycled Al-Si-Mg alloys processed via additive manufacturing achieve 320 MPa tensile strength with 50% energy savings. Nickel alloys, exemplified by γ′-strengthened Inconel 718, maintain >1,200 MPa yield strength at 700°C via Ni 3 (Al,Ti) precipitation, supported by Cr 2 O 3 layers for oxidation resistance. Single-crystal designs (CMSX-4) extend creep lifetimes beyond 10,000 hours at 1,000°C, while additive manufacturing (e.g., Haynes 282) enables complex geometries with 98% density. Challenges—thermal limits in aluminum (~200°C), σ-phase embrittlement in nickel alloys, and machining complexities—are addressed via Sc/Zr microalloying, controlled annealing, and ultrafast laser processing. Environmentally, nickel alloys recycling recovers >95% content via plasma arc melting, aligning with circular economy principles. Collectively, these alloys redefine material capabilities, balancing mechanical robustness, environmental durability, and manufacturing adaptability for applications ranging from additive-manufactured aerospace components to high-temperature turbines and sustainable infrastructure.