Abnormal response of Ti₃Si C₂ to high strain-rate loading

Herein, we report on the response of the MAX phase, Ti3SiC2, to shock wave compression at strain rates above 104s-1. The shock response was determined by measuring the rear, free surface, and velocity of samples - subjected to impact by high-velocity projectiles launched by a gas-gun - using interferometry. The effects of temperature and sample thickness on the dynamic yield and dynamic tensile (spall) strengths were studied. The most important result of this work is the unique dual nature, at high strain rates, of the response of Ti3SiC2, in that it is reminiscent of both metals and ceramics. For low-energy impacts, the elastic response is reminiscent of ductile metals. However, for high-energy impacts, it performed like a hard ceramic with quite high work hardening rates. In other words, Ti3SiC2 behaves like nothing before it and thus must reflect its nanolayered structure. This work not only provides results on the dynamic mechanical properties of Ti3SiC2, but is a critical first step toward understanding the response of ripplocations in layered solids to high strain rates.