Abstract
Experiments were performed to evaluate the dynamic mechanical response of MAX phase material Ti2AlC at high temperature (HT) and under radial confinement. A Split Hopkinson Pressure Bar (SHPB) apparatus was employed to conduct experiments at a strain rate of 500 s−1. High speed photography was used to capture the dynamic response of unconfined specimens. An induction coil was used to heat the specimens from 25 to 1000 °C. Nickel–cobalt–ferrous alloy (Kovar) shrink fit sleeves were utilized to produce a mechanical radial pressure of 30–195 MPa. Unconfined room temperature (RT) and HT experiments revealed that Ti2AlC fails in a gradual, brittle manner (also referred to as graceful failure) with a low dependency on temperature up to 800 °C. All experiments conducted with radial confinement produced a fully plastic response without failure. The addition of hydrostatic confinement increased the maximum compressive stress for all temperatures and allowed specimens to reach strains in excess of 8% without failing. Optical and Scanning Election Microscopy (SEM) images were taken of the cross-section of recovered confined specimens. Imaging revealed conical damage patterns on each end of the specimen which facilitate the plastic response.
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