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Effect of laser shock processing on oxidation resistance of laser additive manufactured Ti6Al4V titanium alloy
摘要： The high-temperature oxidation resistance of laser additive manufactured (LAM) Ti6Al4V before and after laser shock processing (LSP) was investigated. The samples were oxidized at 400?800 °C for 1?50 h in air. The results revealed that the rate of weight gain of the Ti6Al4V fabricated through LAM decreased, and LSP had a positive effect on increasing the oxidation resistance. At an oxidation temperature of 700 °C, an aluminum-rich layer was observed in the cross-section before LSP. After LSP, the aluminum-rich layer changed to three layers. The aluminum-rich layer prevented the diffusion of oxygen, which improved the oxidation resistance of the Ti6Al4V.
关键词： Ti6Al4V titanium alloy,High-temperature oxidation resistance,Laser shock processing,Laser additive manufacturing
更新于2025-09-23 15:21:01
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The New Technologies Developed from Laser Shock Processing
摘要： Laser shock processing (LSP) is an advanced material surface hardening technology that can significantly improve mechanical properties and extend service life by using the stress effect generated by laser-induced plasma shock waves, which has been increasingly applied in the processing fields of metallic materials and alloys. With the rapidly development of modern industry, many new technologies developed from LSP have emerged, which broadens the application of LSP and enriches its technical theory. In this work, the technical theory of LSP was summarized, which consists of the fundamental principle of LSP and the laser-induced plasma shock wave. The new technologies, developed from LSP, are introduced in detail from the aspect of laser shock forming (LSF), warm laser shock processing (WLSP), laser shock marking (LSM) and laser shock imprinting (LSI). The common feature of LSP and these new technologies developed from LSP is the utilization of the laser-generated stress effects rather than the laser thermal effect. LSF is utilized to modify the curvature of metal sheet through the laser-induced high dynamic loading. The material strength and the stability of residual stress and micro-structures by WLSP treatment are higher than that by LSP treatment, due to WLSP combining the advantages of LSP, dynamic strain aging (DSA) and dynamic precipitation (DP). LSM is an effective method to obtain the visualized marks on the surface of metallic materials or alloys, and its critical aspect is the preparation of the absorbing layer with a designed shape and suitable thickness. At the high strain rates induced by LSP, LSI has the ability to complete the direct imprinting over the large-scale ultrasmooth complex 3D nanostructures arrays on the surface of crystalline metals. This work has important reference value and guiding significance for researchers to further understand the LSP theory and the new technologies developed from LSP.
关键词： laser shock processing,stress effect,warm laser shock processing,laser shock marking,laser shock imprinting,laser shock forming
更新于2025-09-23 15:19:57
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Numerical simulation of the surface morphology and residual stress field of IN718 alloy by Gaussian mode laser shock
摘要： Laser shock processing (LSP) is a new surface modification technology that can improve mechanical properties and extending fatigue life. The numerical simulation was utilized in this work, the IN718 alloy was treated by Gaussian mode laser with the laser pulse energy of 3?7 J, laser pulse width of 12 ns and laser spot in diameter of 3 mm. And the effects of laser pulse energy on the surface morphology and residual stress field of material was investigated. The numerical simulation results showed that after the treatment of LSP, the plastic deformation and compressive residual stress layer with a certain depth is formed on the near surface of material. The amount of the plasticity deformation of material was increased with the laser pulse energy. And the compressive residual stress in surface and the direction of depth are increased with the laser pulse energy too. With the laser pulse energy from 3?7 J, the maximum compressive residual stresses are appeared at the center of the surface corresponding to the laser spot. When the laser pulse energy is increased from 3 J–7 J, the plastic deformation in depth is increases from 0.50 μm–1.86 μm, and the maximum compressive residual stress is increased from 362 MPa–742 MPa. In conclusion, LSP can improve mechanical properties of IN718 significantly, and the laser pulse energy is the most important factor to affect the LSP effect. This work can provide a certain theoretical guidance for researchers to study the IN718 alloy treated by LSP.
关键词： Residual stress,Gaussian mode laser,Surface morphology,Laser shock processing,IN718 alloy,Laser pulse energy,Numerical simulation
更新于2025-09-23 15:19:57
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Fatigue Life of Materials Strengthened by Laser Shock Processing
摘要： The influence of the thickness of 03Х22Н6М2 stainless steel samples strengthened by laser shock processing on their fatigue life is investigated by finite-element modeling. This technology is found to increase the fatigue life of thin (2 mm) samples more than threefold.
关键词： finite-element modeling,fatigue life,residual stress,laser shock processing
更新于2025-09-23 15:19:57
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On the Effectiveness of Different Surface Finishing Techniques on A357.0 Parts Produced by Laser-Based Powder Bed Fusion: Surface Roughness and Fatigue Strength
摘要： Laser-based powder bed fusion (L-PBF) is an additive manufacturing (AM) technique that uses a computer-controlled laser beam as the energy source to consolidate a metal powder according to a layer-upon-layer strategy in order to manufacture a three dimensional part. This opens the way for an unprecedented freedom in geometry, but the layer-wise build-up strategy typically results in a very poor surface ?nish, which is a?ected by the staircase e?ect and by the presence of partially molten particles. Surface ?nishing treatments are therefore necessary to obtain an adequate surface ?nish, to improve the fatigue behavior and to meet mechanical and aesthetic needs. The present contribution systematically compares numerous surface ?nishing techniques, including laser shock processing, plastic media blasting, sand blasting, ceramic shot peening and metal shot peening with steel particles of di?erent sizes (φ = 0.2 mm and φ = 0.4 mm). The results show that all the proposed methods improve the surface quality and the fatigue life of A357.0 L-PBF parts. However, the achievement of the lowest surface roughness does not necessarily correspond to the best fatigue performance, thus suggesting that multiple mechanisms may be active and that besides surface roughness also residual stresses contribute to increase the fatigue strength.
关键词： laser shock processing,additive manufacturing,fatigue,shot peening,surface ?nishing,plastic media blasting,sand blasting,surface roughness,A357.0,laser-based powder bed fusion
更新于2025-09-16 10:30:52
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Fatigue crack growth behavior of laser-shock processed aluminum alloy 2024-T3
摘要： Laser shock processing (LSP) is a surface modification technique aimed at enhancing the resistance to wear, corrosion and fatigue of structural alloys. Recently, LSP without coating (LSPwC) has been gaining ground, using lasers with lower energies, shorter pulse duration, smaller laser spots and higher surface coverage per shot. In the present work, LSPwC treatment was performed in both sides of pre-cracked compact tension specimens of aluminum alloy 2024-T3. A pulsed (9 ns) Nd:YAG laser system operating in the second harmonic (532 nm) at 10 Hz repetition rate and with pulse energy of about 270 mJ was positioned with a 500 mm focal distance lens in order to conduct LSPwC with an estimated power density of 5.2 GW/cm2 and two distinct overlapping rates: 50% and 75%. The objective of the work was to investigate the effect of the LSPwC and cyclic load condition on the crack closure and fatigue crack growth (FCG) behavior shown by the samples. Constant amplitude FCG tests were performed with two distinct load ratios: R = 0.2 and R = 0.5. A small increase in the crack closure loads (Pcl ? 1.1-1.2 Pmin) and in the number of cycles to crack propagation was evinced for the specimens tested at R = 0.2 compared to the untreated ones, whereas negligible effect was observed in the R = 0.5 tests. Besides, the obtained results indicate that the increase in overlapping rate is not effective for the adopted LSPwC conditions.
关键词： Laser shock processing,Fatigue crack growth,Aluminum alloy 2024
更新于2025-09-12 10:27:22
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Experimental and Numerical Investigation of Surface Texturing 316L Stainless Steel by Laser Shock Processing
摘要： Surface texturing is considered as a promising method to reduce friction coefficient and improve wear resistance of frictional pairs. In this study, laser peen texturing (LPT) based on laser shock process is proposed to fabricate dimple array on 316L stainless steel. LTP experiments are carried out to investigate the geometrical characteristics of the micro-dimple. It is shown that LPT is capable of fabricating micro-dimples with good repeatability. Numerical simulation based on finite element method is conducted to further study the process of LPT. It is found that the dimple depth obtained from numerical simulation shows a good agreement with that measured from experiments. Moreover, by means of stress analysis, it is shown that residual compressive stress exists in the specimen, which is supposed to be helpful to improve the triboligical performance of frictional pairs.
关键词： friction reduction,wear resistance,316L stainless steel,surface texturing,laser shock processing
更新于2025-09-11 14:15:04