Abnormal response of Ti3SiC2 to high strain-rate loading

Abstract

The authors of this paper have recently shown that deformation in layered solids is not mediated by basal dislocations, as conventional wisdom would have it, but rather by a new mechanism labeled ripplocations. The latter are defects that form in layered materials as a consequence of confined buckling. Here, using shock wave compression---at extremely high strain rates---of Ti${}_{3}$SiC${}_{2}$, a member of the nanolayered MAX-phase family, the authors show that in some ways Ti${}_{3}$SiC${}_{2}$ behaves like a ductile metal but, in others, it behaves more like a hard, brittle ceramic. In other words, the unique dual-nature behavior of Ti${}_{3}$SiC${}_{2}$ is like nothing seen before. The authors attribute this behavior to its nanolayered structure and believe it reflects how ripplocations respond to very high strain rates. This work not only provides new results on the dynamic mechanical properties of Ti${}_{3}$SiC${}_{2}$, but is a critical first step towards understanding the response of ripplocations in layered solids to high strain rates.