Tailoring the microstructure and properties of tungsten-copper composites by minor addition of SiC particles for nuclear fusion reactor application

Abstract

In this work, minor addition of SiC ceramic particles were tested to tailor the microstructure and properties of infiltrated tungsten-copper (W–Cu) composites. The resultant microstructure, density, electrical conductivity, compressive behavior and arc resistant property of the WCu-x wt%SiC (x = 0.5, 1, 2, 3) composites were studied in comparison. The phase constituents of bcc-W, fcc-Cu and hcp-SiC were confirmed by X-ray and electron diffraction techniques. It is also revealed that gradual sintering growth of W particles occurred with the increasing content of SiC under the same processing and sintering parameters. Besides, with the increase of the mixed SiC, the density and electrical conductivity showed a steady decreasing trend due to the retarded rearrangement of W during sintering and the inherently low conductivity of SiC. Specifically, the composite of WCu–2%SiC exhibited the highest room-temperature strength of 1323 MPa and the highest particle-particle contiguity value of 0.373. Moreover, it showed excellent high-temperature arc resistance and compressive properties. Electron backscattering diffraction (EBSD) analysis further validated that the origin of its high damage tolerance can be attributed to its hierarchical microstructure both in grain size and misorientation.