As a progressive surface-hardening technology, laser shock processing (LSP) can enhance the mechanical properties and extend fatigue life for metallic components through laser-generated high-pressure plasma shock waves. In this work, LSP was used to treat titanium alloy Ti-13Nb-13Zr experimental coupons, and the microstructural response and surface mechanical properties of the Ti-13Nb-13Zr experimental coupons were investigated. After the LSP treatment, the X-ray diffraction (XRD) peaks were shifted without any new phase formation. The surface roughness of the experimental coupons increased, which can be explained by the LSP-induced severe plastic deformation. The LSP treatment effectively enhanced the surface compressive residual stress of Ti-13Nb-13Zr. Meanwhile, the microhardness of the Ti-13Nb-13Zr was also obviously increased after the LSP treatment. The experimental results also showed that the number of shocks times is an important factor in the improvement of surface mechanical properties. LSP treatment with multiple shocks can lead to more severe plastic deformation. The surface roughness, surface compressive residual stress and microhardness of the Ti-13Nb-13Zr experimental coupons shocked three times are higher than those after one shock. What is more, grain refinement accounts for the mechanical properties’ enhancements after the LSP treatment.

The titanium alloy thin-walled part with light in weight and high specific strength is widely used in the aviation engine fan, turbine and compressor. The fatigue damage of the thin-walled part often happens under the action of the cyclic loads and high temperatures. Laser shock peening(LSP) is an innovative surface treatment process, which has been used to improve the fatigue life of metallic materials. Considering the shape and size of the thin-walled parts, the TC6 titanium alloy thin-wall parts were treated by the oblique incident laser beam in this work. The purpose of this study is to investigate the effects of multiple oblique LSP on TC6 titanium alloy thin-wall parts. Nd: YLF laser with a wavelength of 1053 nm was applied. The laser incidence angle was determined first by experiment. The effects of laser energies, impact times, pulse durations and pulse frequencies on the surface residual stress, micro-hardness and geometry of TC6 titanium alloy thin-wall parts were investigated. The results showed that by the use of oblique LSP, the higher surface residual stress and surface micro-hardness could be induced on the surface of treated specimens. However, surface deformation and surface roughness of treated specimens can also increase.

Aluminum alloy 6082-T6 is an important material for manufacturing the outer skin of high-speed trains, and laser shock forming can realize the rapid forming of complex-shaped plates. In order to improve the efficiency of the simulation modeling of laser shock forming for aluminum alloy 6082-T6, Python scripting language was used for the secondary development of Abaqus. A plugin was utilized to simulate and analyze the laser shock forming process of aluminum alloy 6082-T6. The coordinates of the plate after laser impact molding were measured using a coordinate measuring machine to calculate the arc bow height of the plate. The accuracy of the simulation model was verified by comparing with the simulation results. The deformation characteristics of plastic strain and arc height of aluminum alloy 6082-T6 under different laser process parameters were analyzed. The simulation plugin has a concise interface, high operability, and accurate results with the other parameters unchanged. When the laser energy is 5 J, 6 J, and 7 J, the corresponding arc heights are 5.9 mm, 6.6 mm, and 7.2 mm, respectively. As the thickness of the sheet increases, the deformation changes from concave at 1 mm to convex at 2 mm, 3 mm, 4 mm, and 5 mm. As the spot size increases from 1 mm to 5 mm, the transmission mode of the shock wave gradually changes from spherical wave to planar wave, and the arc height of the sheet increases from 4.6 mm to 8.2 mm. With the increase in the spot overlap rate, the impact area accumulates residual stress, and the arc height of the sheet is 5.7 mm, 6.6 mm, 7.3 mm, and 8.5 mm, respectively. The secondary development of ABAQUS 2021 using Python 3.6 scripting language has improved the efficiency of simulation modeling and provided reference for rapidly predicting the deformation characteristics of aluminum alloy 6082-T6 under different laser process parameters.

The metallic implants made of Ti13Nb13Zr alloy are usually used under the action of the cyclic loads conditions and fatigue failure occurs occasionally. Laser shock peening (LSP) is an innovative surface treatment process, which has been used to improve the fatigue life of metallic materials. The present research was performed on the Ti13Nb13Zr alloy subject to laser modification in order to determine the effects on the residual stress distribution and surface geometry. A neodymium doped yttrium lithium fluoride (Nd: YLF) pulse laser with a flat-top beam was applied at three different overlapping rates (10%, 30%, 50%), laser pulse energies (5J, 6J, 7J), and impact times (1 impact, 2 impacts, 3 impacts), respectively. The residual stresses were determined by X-ray diffractometer with sin 2ψ method. Firstly, the 30% overlap was chosen by comparing the residual stresses induced by LSP with different overlapping rates. Then, the effects of laser energies and impact times on surface residual stresses, in-depth residual stresses, surface deformation, and surface roughness were investigated and compared. The results showed that the residual stresses, surface deformation, and surface roughness increase with the increasing laser energies and impact times. The effected layer depth of residual stress is about 1058 μ m with the 6J laser energy.

In order to investigate the laws of the laser peening forming process and the effects of laser peening on the surface quality and tensile properties of 5083 aluminum alloy, experiments were conducted utilizing various laser peening paths, energies, and plate thicknesses. Subsequently, laser peening forming experiments were performed on S-shaped and different shapes of aluminum alloy substrates. The impact of different laser peening durations on surface morphology and tensile properties was then analyzed. Results indicated that the largest bending deformation perpendicular to the laser peening path reached 12.5 mm. In cases where the laser peening path was inclined relative to the horizontal direction, torsional deformations were observed in the aluminum alloy plate. For laser energy levels of 5 J, 6 J, and 7 J, deformation amounts were 3.8 mm, 4.9 mm, and 5.4 mm, respectively. Plates with thicknesses of 4 mm exhibited convex deformation, while those with 2 mm thickness showed concave deformation. Furthermore, following one and two laser peening cycles, the residual stresses in the alloy plates were −80 MPa and −107 MPa, the surface hardness increased by 16 HV and 31 HV, the roughness increased by 2.495 μm and 3.615 μm, and the tensile strength increased by 9.5 MPa and 18.5 MPa, respectively.

A systematic investigation was conducted on the laser shock forming (LSF) process of carbon steel Q355ME sheets and practical skin components, focusing on the influence of absorption layer types, laser energy, and impact cycles on forming capacity and surface properties. Three kinds of absorbing layers were compared in the experiment: no absorbing layer, 0.1 mm aluminum foil and 0.12 mm black tape. The results show that when the black tape is used as the absorbing layer, the forming effect is the best, the arc height value reaches 2.63 mm, and the radius of curvature is 1066 mm. Using 0.1 mm thick black tape as the absorption layer and laser parameters of 10% overlap rate, 15 ns pulse width, 4 mm spot, and 1064 nm wavelength, the single impact of 13 J, 15 J, and 17 J, and one, two, and three impacts of 15 J energy were carried out on the plate. It was found that the increase in laser energy and impact times resulted in increases in deformation, surface roughness, microhardness, and residual stress of the plate. The surface work hardening phenomenon of Q355ME plate after laser shock slowed down the increase in these performance parameters. The experimental results show that the laser energy is linearly positively correlated with the residual stress in a certain energy range. Under the optimized laser process parameters, the forming error of the actual skin parts is controlled within ± 0.4 mm, the surface residual stress increases by 368.9%, and the surface microhardness increases by 10.4%. The ultra-high strain plastic deformation and grain refinement on the surface of the sheet were caused by multiple laser shock peenings, which confirmed that LSF technology can improve the formability of carbon steel skin parts and improve its surface properties.