The High Temperature Deformation Behavior of TiC0.98 Grown by the Floating Zone Technique

In order to investigate the high temperature deformation behaviors of TiC0.98, crystals were grown by the radio frequency (r.f.) floating zone technique and were deformed by a compression test at temperatures from 1283 to 2133 K and a strain rate from 5.87 × 10-4 to 6.01 × 10-3s-1. TiC0.98 exhibited a marked work-softening phenomena which is characteristic of covalently bonded materials such as Ge and Si, and the phenomena became less clear with an increasing temperature and with a decreasing strain rate. After the softening, work hardening was observed. The rate hardening decreased as the temperature increased. The stress-strain curve can be explained in terms of the increase in the athermal internal stress and the decrease in the thermal effective stress with the increase in dislocation density by the deformation. The upper yield stress was mainly determined by the frictional resistance to dislocation motion, and the athermal internal stress contribution was very small.