The tolerance of Ti3SiC2 to hydrogen-induced embrittlement: A first principles calculation

• Cleavage fracturing inherent in Ti3SiC2 is not aggravated by hydrogen because the chain of Ti2-C-Ti1-C-Ti2-Si as a constructing unit of the crystal remains intact when hydrogen presented.
• Hydrogen interstitials primarily hybridize with the s states of the neighboring Si atoms, and thus the p-d hybridization between Si-Ti atoms for binding the two atoms in the atomic chain does not significantly disturbed by hydrogen.
• The behavior of hydrogen in Ti3SiC2 is different from metals in nature.

Ti3SiC2, a layered ternary compound material combining the ceramic and metal properties, is considered one of candidate materials in nuclear industry. However, the problems of hydrogen embrittlement commonly existing in metals have not been investigated yet. Using the first-principles calculation, we investigated the effect of hydrogen on the cleavage characteristics of Ti3SiC2. It was found that cleavage fracturing inherent in Ti3SiC2 is not aggravated because the chain of Ti2–C–Ti1–C–Ti2–Si as a constructing unit of the crystal remains intact when hydrogen presented. The mechanical response of Ti3SiC2 to hydrogen is different from metals in nature.

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