Damage effect of high-energy laser on 2A12 aluminum alloy under boundary preload

High-energy laser weapons have gradually emerged as a critical new destructive capability on modern battlefields, complementing traditional kinetic weapons. In real service conditions of aircraft, external structures such as skins are subjected to long-term cyclic loads due to air pressure. Therefore, it is essential to consider the influence of boundary loads when studying laser-induced damage. Focusing on the problem of high-energy laser damage effects under boundary loading conditions, this study conducted experiments on a typical 2A12 aerospace aluminum alloy under high-energy continuous laser irradiation. By integrating a boundary preload loading apparatus, the effects of boundary preloads on material response and damage behavior were analyzed. It was found that the primary damage mode under continuous high-energy laser irradiation involves molten material flowing downward under gravitational forces to form perforations. Under boundary preload conditions, thermo-expansion and thermal softening jointly influence the thermomechanical response of the target. Observations of boundary load curves during the ablation process revealed three distinct stages. After laser irradiation ceased, residual boundary loads in tensile and compressive preloading conditions recovered to approximately 80% and 25%, respectively, indicating irreversible damage akin to plastic deformation. Furthermore, a thermomechanical coupling simulation model incorporating phase transformation and material flow was established based on experimental results. By analyzing the degradation pattens of thermal expansion coefficients and elastic modulus, the roles of thermo-expansion and thermal softening during laser ablation were elucidated.