Selective laser melting of high-performance pure tungsten: parameter design, densification behavior and mechanical properties

• Published in: Science and technology of advanced materials Vol. 19; no. 1; pp. 370 - 380
• Main Authors: Tan, Chaolin, Zhou, Kesong, Ma, Wenyou, Attard, Bonnie, Zhang, Panpan, Kuang, Tongchun
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 31.12.2018; Taylor & Francis Ltd; Taylor & Francis Group
• Subjects: 10 Engineering and Structural materials; 106 Metallic materials; 210 Thermoelectronics / Thermal transport / insulators; 303 Mechanical / Physical processing; 305 Plasma / Laser processing; Additive manufacturing; Compressive strength; Densification; Design parameters; Electron backscatter diffraction; Engineering and Structural materials; Laser beam melting; laser parameter; Lasers; linear energy; Mathematical analysis; Mechanical properties; molten pool; parameter design; Process parameters; property; Rapid prototyping; refractory metal; Refractory metals; selective laser melting; Temperature gradients; Theoretical density; Thickness; Tungsten; densification; laser parameter; 210 Thermoelectronics / Thermal transport / insulators; molten pool; Additive manufacturing; parameter design; 10 Engineering and Structural materials; 106 Metallic materials; tungsten; 303 Mechanical / Physical processing; linear energy; property; refractory metal; selective laser melting; 305 Plasma / Laser processing
• DOI: 10.1080/14686996.2018.1455154
• ISSN: 1468-6996

Selective laser melting (SLM) additive manufacturing of pure tungsten encounters nearly all intractable difficulties of SLM metals fields due to its intrinsic properties. The key factors, including powder characteristics, layer thickness, and laser parameters of SLM high density tungsten are elucidated and discussed in detail. The main parameters were designed from theoretical calculations prior to the SLM process and experimentally optimized. Pure tungsten products with a density of 19.01 g/cm 3 (98.50% theoretical density) were produced using SLM with the optimized processing parameters. A high density microstructure is formed without significant balling or macrocracks. The formation mechanisms for pores and the densification behaviors are systematically elucidated. Electron backscattered diffraction analysis confirms that the columnar grains stretch across several layers and parallel to the maximum temperature gradient, which can ensure good bonding between the layers. The mechanical properties of the SLM-produced tungsten are comparable to that produced by the conventional fabrication methods, with hardness values exceeding 460 HV 0.05 and an ultimate compressive strength of about 1 GPa. This finding offers new potential applications of refractory metals in additive manufacturing.