Microstructure and mechanical behavior of porous tungsten skeletons synthesized by selected laser melting

Zhou, Kai, Chen, Wenge, Yang, Yana, Li, Rong, Dong, Longlong and Fu, Yong Qing (2022) Microstructure and mechanical behavior of porous tungsten skeletons synthesized by selected laser melting. International Journal of Refractory Metals and Hard Materials, 103. p. 105769. ISSN 0263-4368

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Official URL: https://doi.org/10.1016/j.ijrmhm.2021.105769

Abstract

Because of its high ductile-brittle transition temperature, tungsten (W) is normally alloyed with other metal elements in order to obtain high fracture strength, excellent thermal and electrical properties for industrial applications. For tungsten samples sintered using the conventional powder metallurgy methods, bonding among tungsten particles is normally through sintered necking process, thus without providing a good metallurgical bonding strength. In this paper, we proposed to apply additive manufacture methodology to synthesize two types of porous tungsten skeleton structures, honeycomb (65% porosity) and square skeleton (80% porosity), using a selective laser melting (SLM) method. Results showed that for both these skeleton structures, grains in the XY plane showed an equiaxed crystal appearance, whereas those in the YZ/XZ plane showed columnar patterns parallel to the Z axis. The measured porosities for these two types of skeletons were 52 vol% and 68 vol%, and their compressive strength values were 256 MPa and 149 MPa, respectively. Both their compressive strengths and hardness showed anisotropic behaviors, with their highest values along the direction of Z axis. Results also showed that fracture morphology and mechanisms of these skeletons under compression were quite different when they were compressed along different directions, mainly due to the formed columnar crystals of the skeletons along the Z axis. Fracture morphology along the Z axis showed transgranular fracture and tearing features, whereas those along X axis showed only intergranular fracture features.

Item Type: Article
Additional Information: Funding information: The authors would like to acknowledge the financial supports from Xi’an Science Research Project of China (No. 2020KJRC0089) and Shaanxi Coal Industry Group United Fund of China (No.2019JLM-2), Shaanxi Key Research and Development Plan of China(2019GY-188), National Natural Science Foundation of China (No.51901192), and Electrical Materials and Infiltration Key Laboratory of Shaanxi Province, and International Exchange Grant (IEC/NSFC/201078) through Royal Society UK and the National Natural Science Foundation of China, and Royal academy of Engineering UK-Research Exchange with China and India.
Uncontrolled Keywords: Selective laser melting, Porous tungsten, Microstructure, Fracture mechanism
Subjects: F300 Physics
H300 Mechanical Engineering
H900 Others in Engineering
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 04 Jan 2022 09:40
Last Modified: 04 Jan 2022 09:45
URI: http://nrl.northumbria.ac.uk/id/eprint/48053

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