Thermophysical Properties of Ti3SiC2 MAX Phase Composites with SiC Reinforcement

In the present work, dense (similar to 100%) Ti3SiC2 composites (TSC) are processed along with 20 vol% of SiC reinforcement (TSC20) via spark plasma sintering at 1400 degrees C, 40 MPa, 15 min, and dynamic vacuum environment. Thermal expansion of both the composites increases from RT to 1273 K and linear fitting of data yields coefficient of thermal expansion (CTE) of 9.4 x 10(-6) K-1 for TSC which decreases to 8.3 x 10(-6) K-1 for TSC20. With increase in temperature from RT to 773 K, specific heat for both TSC and TSC20 composites is observed to increase from 598-850 J.kg-1.K-1, whereas thermal diffusivity and thermal conductivity values decrease with testing temperature. SiC reinforcement in Ti(3)SiC(2 )resulted in improved thermal diffusivity from 12.7 to 18.7 mm(2).s(-1) and thermal conductivity from similar to 57 to similar to 79 W.m(-1).K-1 at RT. However, with increase in temperature (773 K), thermal diffusivity and conductivity decrease, and values get closer for both TSC and TSC20 composites. Further extrapolation of thermal conductivity data showed cross-over at similar to 973 K due to domination of phonon-phonon scattering and thus lower values of thermal conductivity for TSC20 than TSC. Therefore, reduced CTE and higher thermal conductivity of TSC20 make it a viable choice for applications in high temperatures. [GRAPHICS] .