| 摘要: |
| 增材制造技术可实现复杂结构的无模具，快速、近净成形，高致密度。为保证零件的成形质量，建立金属增材制造技术工艺参数—微观结构—宏观力学性能的关联机制十分关键。采用选区激光熔化技术(SLM)制备四种不同工艺参数组合的 Ti-6Al-4V 合金(又称 TC4)，对比和讨论试件微观形貌。通过单轴拉伸试验从宏观角度研究准静态条件下材料本构行为，并确定流动应力和应变极限等关键力学性能参数，通过纳米压痕试验从微观角度研究 0.01 / s 和 0.10 / s 压痕应变率下材料荷载位移曲线，并基于连续刚度法获取材料弹性模量和硬度。最后通过引入约束因子和位错密度，结合单轴拉伸和纳米压痕试验所得的力学性能，讨论 SLM 成形过程中激光能量输入密度对 TC4 材料宏观力学性能的影响规律。通过开展工艺参数与力学性能的相关性分析，从更具统计意义的角度阐明 SLM 工艺参数—微观结构—宏观力学性能的关联机制，进而更加有效地确定可用于调控 SLM 成形 TC4 材料宏观力学性能的工艺参数优化组合。研究结果可为提升 TC4 材料力学性能的 SLM 成形工艺参数提供指导。 |
| 关键词: 选区激光熔化 TC4 微观形貌 力学性能 工艺参数优化 |
| DOI：10.11933/j.issn.1007-9289.20210924002 |
| 分类号:TG156;TB114 |
| 基金项目: |
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| Mechanical Properties and Parameter Optimization of TC4 Alloy by Additive Manufacturing |
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LONG Xu1, JIA Qipu1, LI Jiao1, CHONG Kainan1, DU Leiming2, PAN Xiangnan2, CHANG Chao3
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1.School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University,Xi’ an 710072 , China;2.State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences,Beijing 100190 , China;3.School of Applied Science, Taiyuan University of Science and Technology,Taiyuan 030024 , China
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| Abstract: |
| Additive manufacturing can realize die free, rapid and near net shape of complex structures with high densities. In order to ensure the forming quality of manufactured components, it is critical to establish a correlation mechanism between processing parameters, microstructure, and macro-mechanical properties in the additive manufacturing for metals. The Ti-6Al-4V alloy (referred to as TC4) is created by selective laser melting (SLM) using four distinct processing settings, and the microstructures are compared and discussed. The constitutive behavior is studied by uniaxial tensile tests under quasi-static conditions to determine the key mechanical properties such as flow stress and ultimate strain. The load-displacement curves of the TC4 alloy under the indentation strain rates of 0.01 / s and 0.10 / s are studied by nanoindentation experiments, in which the Young’s modulus and hardness are obtained based on the continuous stiffness method. Finally, the effect of laser energy density during the SLM processing on the macro-mechanical properties of TC4 alloy is discussed by adopting the concepts of constraint factor and dislocation density, which combines the mechanical properties obtained from uniaxial tension and nanoindentation experiments. From a statistical standpoint, a correlation analysis is performed between SLM processing parameters and mechanical properties to elucidate the prevailing pathways among SLM processing parameters, microstructural morphology, and macro-mechanical properties. As a result, the most effective combination of processing parameters is identified and then used to tune the macro-mechanical properties of SLM-fabricated TC4 alloy. A guidance is provided for the SLM forming process parameters to improve the mechanical properties of TC4 material. |
| Key words: selective laser melting TC4 microstructure mechanical properties optimal processing parameters |
