Interfacial reactions and mechanical properties of W–SiC in-situ joints for plasma facing components

Joints of tungsten and SiC were produced by a hot-pressing method and characterized on interfacial reaction and ambient temperature mechanical properties. Reaction phases were identified and the diffusion path was demonstrated by means of quantitative analysis. Four distinctive reaction phases, namely tungsten silicides (WSi2, W5Si3) and tungsten carbides (WC, W2C), were formed in various processing conditions. Complex reactions were confirmed in tungsten-SiC diffusion pair, and the diffusion path was experimentally verified as SiC/WSi2/WC/W5Si3/W2C/W. Mechanical properties of the joints were evaluated by flexural and shear tests. Joint shear strength as high as ∼90 MPa was obtained even when substantial interfacial reaction occurred, however, excessive growth of the reaction layer caused a severe degradation in strength.