Processing and mechanical properties of Ti3SiC2:: II, effect of grain size and deformation temperature

In this article, the second part of a two-part study, we report on the mechanical behavior of Ti3SiC2, In particular, we have evaluated the mechanical response of fine-grained (3-5 mu m) Ti3SiC2 in simple compression and flexure tests, and we have compared the results with those of coarse-grained (100-200 mu m) Ti3SiC2, These tests have been conducted in the 25 degrees-1300 degrees C temperature range. At ambient temperature, the fine- and coarse-grained microstructures exhibit excellent damage-tolerant properties. In both cases, failure is brittle up to similar to 1200 degrees C, At 1300 degrees C, both microstructures exhibit plastic deformation (>20%) in flexure and compression. The fine-grained material exhibits higher strength compared with the coarse-grained material at all temperatures. Although the coarse-grained material is not susceptible to thermal shock (up to 1400 degrees C), the fine-grained material thermally shocks gradually between 750 degrees and 1000 degrees C, The results presented herein provide evidence for two important aspects of the mechanical behavior of Ti3SiC2: (i) inelastic deformation entails basal slip and damage formation in the form of voids, grain-boundary cracks, kinking, and delamination of individual grains, and (ii) the initiation of damage does not result in catastrophic failure, because Ti3SiC2 can confine the spatial extent of the damage.