Selective laser melting additive manufacturing of pure tungsten: Role of volumetric energy density on densification,microstructure and mechanical properties |
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| Affiliation: | 1. Global Tungsten and Powders Corp., Towanda, USA;2. University of Louisville, Louisville, USA;1. KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, B-3001 Heverlee, Belgium;2. KU Leuven, Department of Mechanical Engineering, Member of Flanders Make, Celestijnenlaan 300B, B-3001 Heverlee, Belgium;1. College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu Province, PR China;2. Jiangsu Provincial Engineering Laboratory for Laser Additive Manufacturing of High-Performance Metallic Components, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu Province, PR China;1. State Ley Laboratory of New Ceramic and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;2. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden;3. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China;4. University of Science and Technology of China, Hefei 230026, China |
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| Abstract: | Due to the intrinsic properties of tungsten, such as high melting point and high thermal conductivity, selective laser melting of pure W parts experiences many challenges. In this study, the effects of volumetric energy density on the densification behavior, microstructure evolution and mechanical performances of SLM-processed pure tungsten parts were investigated. A maximum density of 19.0 g/cm3 (98.4% of the theoretical density) was obtained at the optimal energy density of 1000 J/mm3 and its microstructure was free of pores and balling phenomenon. The formation mechanism of pores and cracks was systematically investigated. The microhardness and compressive strength of SLM-processed pure W parts reached 474 HV and 902 MPa, respectively, which were comparable to the samples produced by conventional manufacturing methods. The morphology of fracture demonstrated that the fracture mechanism of SLM-processed pure W parts was brittle fracture and intergranular fracture was the main fracture mode. Dry sliding wear tests showed that the wear mechanism changed with the energy density. For pure W parts processed by SLM at the optimal parameters, the adhesion of hardened tribolayers was formed. In this case, the reduced coefficient of friction (COF) of 0.45 and a low wear rate of 1.3 × 10−5 mm3·N−1·m−1 were obtained. |
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