Plastic deformation of single crystals of TiSi2 with the C54 structure

The deformation behavior of single crystals of TiSi₂ with the orthorhombic C54 structure has been investigated as a function of crystal orientation in the temperature range from room temperature to 1400 °C in compression. Plastic flow is possible only when slip along 〈 110 〉 on (001) is operative and no other slip systems are observed in the whole temperature range investigated. While plastic flow is observed above 300 °C for as-grown crystals, the onset temperature for plastic flow is lowered considerably down to room temperature when the crystal is prestrained at 1300 °C and then re-deformed at low temperatures. The critical resolved shear stress (CRSS) for (001) 〈 110 〉 slip decreases with increasing temperature, exhibiting a moderate peak (or plateau) in the temperature range from 800 to 1100 °C. The deformation mechanism of TiSi₂ is discussed in comparison with those reported for other transition-metal disilicides with the C11_b and C40 structures, which are closely related to the C54 structure of TiSi₂.