| 摘要: |
| 针对透平叶片易受点蚀、水蚀甚至断裂的问题，采用25 mm×8 mm矩形光斑激光固溶时效对17-4PH沉淀硬化不锈钢进行表面强化，利用光学显微镜、XRD、SEM、EBSD、显微硬度计、拉伸试验机对激光固溶硬化层的显微组织、物相、硬度、拉伸性能进行了测试和分析。结果表明：与传统固溶时效相比，激光固溶硬化层有明显的ε-Cu与残余奥氏体的衍射峰，激光快速加热、冷却条件下形成的高密度位错、空位等显微缺陷有利于时效过程中析出ε-Cu、NbC等强化相，其与高密度位错的交互作用使得位错运动能量增高；同时激光固溶硬化层最大厚度约3.5 mm（HV>400），硬度最高达500 HV，比基体高130~140 HV，且从表及里呈梯度分布；测试其抗拉强度为1 290 MPa，约为未处理叶片基体的1.5倍，同时保持良好的塑性，完全适用于需局部选区固溶时效强化的透平叶片。 |
| 关键词: 激光固溶 矩形光斑 17-4PH 力学性能 显微组织 |
| DOI：10.11933/j.issn.1007-9289.20171201001 |
| 分类号:TG174.44 |
| 基金项目: |
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| Mechanical Properties of 17-4PH Stainless Turbine Blades by Laser Solution and Aging |
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DU Jin-zheng1, LU Yuan-yuan2, CHEN Hao1, GUO Xi-xi1, LIN Shou-gang1, LIU De-jian1
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1.State Key Laboratory of Material Processing and Die Mould Technology, Huazhong University of Science and Technology, Wuhan 430074;2.School of Engineering Technology, Hubei University of Technology, Wuhan 430068
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| Abstract: |
| Laser solid solution and aging with a rectangular laser beam of 25 mm×8 mm was performed on 17-4PH precipitation-hardening stainless steel for surface strengthening to resolve pitting, water erosion and fracture of turbine blades. The treated samples were characterized by optical microscopy (OM), X-ray diffraction (XRD), SEM, EBSD, microhardness tester and tensile tester. Results show that the laser solid solution hardening layer has obvious diffraction peaks of ε-Cu and retained austenite compared with the traditional solid solution. The rapid heating and cooling of laser solid solution has a positive effect on the formation of high density dislocation and vacancy. The interactions between the precipitated second phase particles, such as ε-Cu and NbC, with the high density of dislocations increase the energy of dislocation movement. The thickness of the hardening layer is about 3.5 mm (HV>400), and a hardness gradient of 130~140 HV exists in hardening layer, while the highest hardness is 500 HV on the surface. The hardening layer shows a good plasticity with a tensile strength of 1 290 MPa, which is 1.5 times of the substrate. Thus, the laser solid solution is a suitable candidate for an application in the turbine blades. |
| Key words: laser solution rectangular laser beam 17-4PH mechanical property microstructure |
