Microstructure and mechanical properties of porous Ti3SiC2

A ~43 vol.% porous Ti3SiC2 ternary compound was fabricated by the reactive sintering of elemental powders. Under cyclic compression, the first loading cycle resulted in a measurable deformation, but subsequent cycles to the same load resulted in fully reversible, closed hysteresis loops that were smaller in area than the first loop. Cyclic nanoindentation loadings on solid bridges separating pores displayed behavior that was qualitatively similar to the uniaxial compression testing results. The results are interpreted in light of our kink band formation model. The significantly larger areas associated with the porous material than the fully dense sample with comparable grain size are ascribed to the formation of more incipient and regular kink bands as a consequence of the lack of constraint due to the presence of pores. The technological implications of having a porous material that dissipates more energy - on an absolute scale - than its fully dense counterpart are discussed.