金属热处理 ›› 2023, Vol. 48 ›› Issue (11): 161-167.DOI: 10.13251/j.issn.0254-6051.2023.11.025

• 工艺研究 • 上一篇    下一篇

热处理对SLM成形TiN/AlSi10Mg合金复合材料组织性能及残余应力的影响

黄卫东1,2, 王璐2, 黄旭1,2, 成徐珩1,2   

  1. 1.福建省智能加工技术及装备重点实验室, 福建 福州 350118;
    2.福建理工大学 机械与汽车工程学院, 福建 福州 350118
  • 收稿日期:2023-06-20 修回日期:2023-09-26 出版日期:2023-11-25 发布日期:2023-12-27
  • 作者简介:黄卫东(1971—),男,教授,主要研究方向为增材制造技术、先进制造工艺与装备,E-mail:hwd@fjut.edu.cn
  • 基金资助:
    国家自然科学基金青年基金(52205340);福建省自然科学基金青创项目(2021J05214)

Effect of heat treatment on microstructure, properties and residual stress of TiN/AlSi10Mg alloy composites fabricated by SLM

Huang Weidong1,2, Wang Lu2, Huang Xu1,2, Cheng Xuheng1,2   

  1. 1. Fujian Key Laboratory of Intelligent Machining Technology and Equipment, Fuzhou Fujian 350118, China;
    2. School of Mechanical and Automotive Engineering, Fujian University of Technology, Fuzhou Fujian 350118, China
  • Received:2023-06-20 Revised:2023-09-26 Online:2023-11-25 Published:2023-12-27

摘要: 为了进一步提高样件力学性能和消除成形过程的残余应力,研究了不同热处理工艺(时效、去应力退火、固溶+人工时效(T6))对SLM(selective laser melting)成形TiN/AlSi10Mg合金复合材料的组织性能和残余应力的影响。结果表明,成形态样品的平均硬度为136.2 HV0.2,抗拉强度为397.7 MPa,伸长率12.5%,显微组织由初生α-Al基体和亮白色网状共晶Si组成。对成形态样品进行T6 处理后,连续的Al-Si共晶结构在520 ℃、2 h下解体,离散的Si颗粒发生Ostwald熟化,伸长率(11.0%)与成形态样品相近,抗拉强度降至239.1 MPa。经过250 ℃×2 h去应力退火处理后,少量网状Si边界出现球化现象,抗拉强度和伸长率分别下降至344.9 MPa和8.8%。经160 ℃×6 h时效处理后,SLM成形过程中形成的a-Al/Si共晶组织基本保留,残余应力降低了78.9%,同时又促进了纳米级Si相和Mg2Si强化相的析出,获得了最佳材料力学性能,其硬度为143.5 HV0.2,抗拉强度为408.7 MPa,伸长率为15.3%。此结果表明,采用适当的时效处理可以获得最佳的综合力学性能,同时还能显著降低残余应力。

关键词: 增材制造, 选区激光熔化, TiN/AlSi10Mg合金复合材料, 热处理, 力学性能

Abstract: Selective laser melting (SLM) was used to prepare TiN/AlSi10Mg alloy composites. In order to further improve the mechanical properties of the specimen and eliminate the residual stress in the forming process, different heat treatment processes (aging, stress relief annealing, T6) were selected for microstructure regulation. The results show that the average hardness of the formed specimens is 136.2 HV0.2, the tensile strength is 397.7 MPa, the elongation is 12.5%, and the microstructure is composed of primary α-Al matrix decorated with brilliant white eutectic Si networks. After T6 treatment on the SLM specimens, the continuous Al-Si eutectic structure disintegrates at 520 ℃ and 2 h, and the discrete Si particles undergo Ostwald ripening, the elongation (11.0%) is similar to that of the formed specimen, and the tensile strength decreases to 239.1 MPa. After stress relief annealing treatment at 250 ℃ for 2 h, a small number of mesh Si boundaries are spheroidized, and the tensile strength and elongation decrease (344.9 MPa, 8.8%). After aging at 160 ℃ for 6 h, the fine a-Al/Si eutectic structure formed during SLM forming is basically retained, while the residual stress is reduced by 78.9%, and at the same time, the precipitations of nanoscale Si phase and Mg2Si strengthening phase are promoted, the optimal mechanical properties are obtained with the hardness of 143.5 HV0.2, tensile strength of 408.7 MPa, and elongation of 15.3%. It is shown that an appropriate aging treatment can be used to obtain the best comprehensive mechanical properties, and also significantly reduce the residual stress.

Key words: additive manufacturing, selective laser melting, TiN/AlSi10Mg alloy composites, heat treatment, mechanical properties

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