王文泉,赵新甜,于文慧,郑宏宇,王宗申.激光冲击强化对增材制造镁合金表面完整性的影响[J].表面技术,2025,54(11):173-183.
WANG Wenquan,ZHAO Xintian,YU Wenhui,ZHENG Hongyu,WANG Zongshen.Effect of Laser Shock Peening on Surface Integrity of Additively Manufactured Mg Alloy[J].Surface Technology,2025,54(11):173-183 |
| 激光冲击强化对增材制造镁合金表面完整性的影响 |
| Effect of Laser Shock Peening on Surface Integrity of Additively Manufactured Mg Alloy |
| 投稿时间：2024-12-09 修订日期：2025-04-10 |
| DOI：10.16490/j.cnki.issn.1001-3660.2025.11.014 |
| 中文关键词: 激光冲击强化 选区激光熔化 增材制造 AZ91镁合金 表面完整性 缺陷调控 |
| 英文关键词:laser shock peening selective laser melting additive manufacturing AZ91 Mg alloy surface integrity defect regulation |
| 基金项目:国家自然科学基金项目(51605266);山东省自然科学基金项目(ZR2022ZD07，ZR2023ME134);山东省高等学校青创科技支持计划项目(2021KJ068) |
| 作者 | 单位 |
| 王文泉 | 山东理工大学 激光高端制造研究中心 机械工程学院，山东 淄博 255000 |
| 赵新甜 | 山东理工大学 激光高端制造研究中心 机械工程学院，山东 淄博 255000 |
| 于文慧 | 山东理工大学 激光高端制造研究中心 机械工程学院，山东 淄博 255000 |
| 郑宏宇 | 山东理工大学 激光高端制造研究中心 机械工程学院，山东 淄博 255000 |
| 王宗申 | 山东理工大学 激光高端制造研究中心 机械工程学院，山东 淄博 255000 |
|
| Author | Institution |
| WANG Wenquan | Centre for Advanced Laser Manufacturing School of Mechanical Engineering, Shandong University of Technology, Shandong Zibo 255000, China |
| ZHAO Xintian | Centre for Advanced Laser Manufacturing School of Mechanical Engineering, Shandong University of Technology, Shandong Zibo 255000, China |
| YU Wenhui | Centre for Advanced Laser Manufacturing School of Mechanical Engineering, Shandong University of Technology, Shandong Zibo 255000, China |
| ZHENG Hongyu | Centre for Advanced Laser Manufacturing School of Mechanical Engineering, Shandong University of Technology, Shandong Zibo 255000, China |
| WANG Zongshen | Centre for Advanced Laser Manufacturing School of Mechanical Engineering, Shandong University of Technology, Shandong Zibo 255000, China |
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| 中文摘要: |
| 目的 改善增材制造镁合金的表面完整性。方法 利用激光冲击强化技术对选区激光熔化制备的AZ91镁合金板材进行不同冲击次数的表面后处理。通过扫描电子显微镜与激光共聚焦显微镜、显微硬度测量和残余应力测试分析，分别评价增材制造镁合金的表面形貌及粗糙度、显微硬度和残余应力水平，并通过光学显微镜、电子背散射衍射和X射线衍射对增材制造镁合金的微观组织和气孔缺陷进行分析。结果 激光冲击强化后，试样表面未熔颗粒及其团聚现象得到改善，表面区域平整光滑，粗糙度随冲击次数的增加逐渐降低(由初始的15.47 μm降低至8.87 μm)，降幅约43%;表面显微硬度由103.04HV提高至160.81HV，提高幅度约为56%，截面显微硬度沿深度方向呈梯度分布且在冲击2次时最为显著，影响深度约为400 μm;表面残余压应力由初始的3.52 MPa增至24.02 MPa。同时，激光冲击强化试样内部孔洞缺陷数量大幅下降且孔洞形态发生改变，并在近表层形成梯度微观结构与晶粒细化。结论 在激光诱导的高温高压等离子体冲击波的力学效应与热效应的共同作用下，增材制造镁合金试样的表面完整性得到显著改善。 |
| 英文摘要: |
| Mg alloys have drawn considerable attention in the biomedical field due to their superior biological properties, ultra-low density close to human bone, and no stress shielding phenomenon. Owing to its capability of fabricating geometrically complex structures, additive manufacturing has provided unprecedented opportunities to produce biodegradable metallic implants especially using Mg alloys. However, defects such as porosity, residual tensile stress and anisotropy resulted from the high cooling rates, high temperature gradients and multiple transient cycles greatly limit further applications of Mg alloys produced by additive manufacturing. Laser shock peening (LSP) stands as an innovative surface treatment technique by inducing intense plastic deformation and residual compressive stress at the material surface with a significant affecting depth. Thus, in this work, to improve the surface integrity and expand the application range of additively manufactured Mg alloys, the surface of AZ91 Mg alloy sheets prepared by selective laser melting (SLM) is creatively post-treated by employing different number of LSP and the effect of impact number on surface integrity of the alloy is investigated. The surface morphology and roughness, microhardness and residual stress level of additively manufactured Mg alloys are evaluated by scanning electron microscope, laser scanning confocal microscope, microhardness measurement and residual stress test, respectively. The evolution of microstructure and porosity defects of the alloy samples are analyzed by optical microscope, electron back-scattered diffraction (EBSD) and X-ray diffraction (XRD). The results show that, after LSP, the unmelted particles and their agglomeration phenomenon on the sample surface are evidently reduced and the surface tends to be flat and smooth. The surface roughness is decreased with the increase of impact number from the initial 15.47 μm to 8.87 μm after 4 impacts by about 43%. The surface microhardness is increased from 103.04HV to 160.81HV with an increase of about 56%. The cross-sectional microhardness exhibits a gradient distribution along the depth direction, which is the most significant after 2 impacts, and the affecting depth is around 400 μm. The residual compressive stress is raised from the initial 3.52 MPa to 24.02 MPa. Meanwhile, the additively manufactured samples experience a prominent decrease in the number of internal porosity defects and the porosity morphology is evidently changed after LSP. Besides, gradient microstructure and grain refinement near the sample surface is introduced. The average grain size of the sample subsurface is refined from the initial 5.36 μm to 1.68 μm after 4 impacts, and a crystalline size of about 255 nm estimated by XRD results is finally obtained. In conclusion, the surface integrity of the additively manufactured Mg alloy samples is effectively improved by the combined action of the mechanical effect and the thermal effect generated by the laser-induced high-temperature and high-pressure plasma shock wave during LSP. The effect of LSP is gradually promoted by increasing impact number whereas basically the optimum results are achieved after 2 impacts and further repetition brings no more benefits. The availability and efficiency of LSP as a promising post-treatment technique utilized for improving surface integrity and related properties as well as enhancing their performance of additively manufactured Mg alloys are innovatively tried and proved in this work. |
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