Influence of proton-irradiation temperature on the damage accumulation in Ti3SiC2 and Ti3AlC2

The effect of irradiation temperature on the crystallographic stability of the ternary carbides Ti₃SiC₂ and Ti₃AlC₂ was investigated in the 350 to 600 °C temperature range, using 2 MeV protons to a fluence of 2.25 × 10¹⁸ protons cm⁻². Both materials shrink along the basal planes and expand normal to them. Defect recovery decreases the magnitude of these anisotropic lattice changes with increasing irradiation temperature. However, reduced recovery in Ti₃AlC₂ causes irradiated surface exfoliation at low temperatures and elevated damage rates. The extent of lattice change suggests that in-reactor use of these compositions will likely be limited to high-temperature applications.