Metallurgical Abstracts on Light Metals and Alloys vol. 58

Enhanced deformability of TiC in Mo-Ti-C ternary system by off-stoichiometry

Shuntaro Ida*, Eri Nakagawa**, Viola Paul**, Takahito Ohmura** and Kyosuke Yoshimi*
* Department of Materials Science, Graduate School of Engineering, Tohoku University
** Research Center for Structural Materials, National Institute for Materials Science

[Published in Materilalia, 40, (2025)]

https://doi.org/10.1016/j.mtla.2025.102412
E-mail: shuntaro_ida[at]jfcc.or.jp
Key Words: Deformation, TiC, Off-stoichiometry, Micropillar compression

The deformation behavior of B1-type stoichiometric TiC and off-stoichiometric (Ti_0.96, Mo_0.04)C_0.67 was investigated by micropillar compression test utilizing an in situ scanning electron microscope. The yield stress of (Ti_0.96, Mo_0.04)C_0.67 was found to be sufficiently lower than that of the stoichiometric TiC. In addition, the {001}<110>, {110}<110>, and {111}<110> slip systems were identified to be active during the plastic deformation of (Ti_0.96, Mo_0.04)C_0.67. The critical resolved shear stresses of these slip systems decreased in the following order: {110}<110> (5.6 GPa), {001}<110> (5.0 GPa), and {111}<110> (4.4 GPa). In contrast to the stoichiometric TiC, which underwent complete fracture at a relatively early stage of deformation, (Ti_0.96, Mo_0.04)C_0.67 deformed under >10% plastic strain without fracturing, with crack preferentially initiating along the {001} plane. The findings demonstrate that the off-stoichiometry of (Ti_0.96, Mo_0.04)C_0.67 improves plastic deformability and has a suppressive effect on crack propagation. The enhanced deformability may be attributed to the significantly reduced shear modulus caused by off-stoichiometry.