High temperature properties of the monolithic CVD β-SiC materials joined with a pre-sintered MAX phase Ti3SiC2 interlayer via solid-state diffusion bonding

摘要

Monolithic high purity CVD β-SiC materials were successfully joined with a pre-sintered Ti_3SiC_2 foil via solid-state diffusion bonding. The initial bending strength of the joints (~ 220 MPa) did not deteriorate at 1000 °C in vacuum, and the joints retained ~ 68 % of their initial strength at 1200 °C. Damage accumulation in the interlayer and some plastic deformation of the large Ti_3SiC_2 grains were found after testing. The activation energy of the creep deformation in the temperature range of 1000 - 1200 °C in vacuum was ~ 521 kjmol~(-1). During the creep, the linkage of a significant number of microcracks to form a major crack was observed in the interlayer. The Ti_3SiC_2 interlayer did not decompose up to 1300 °C in vacuum. A mild and well-localized decomposition of Ti_3SiC_2 to TiC_x was found on the top surface of the interlayer after the bending test at 1400 °C in vacuum, while the inner part remained intact.