Decohesion of Ti3SiC2 induced by He impurities

Using the first principle method, we investigated the effect of He impurities on the properties of layered Ti3SiC2. Helium usually segregates near Si planes. The evolution of He weakens the cohesion between Si–Ti layers, and intensifies delamination in a way of cleaving between Ti and Si layers. As a consequence, the effect of He impurities on weakening the mechanical properties of Ti3SiC2 has to be considered when such Ti3SiC2 materials are chosen as high temperature structural materials.

► MAX phase materials possess properties integrated metallic and ceramic attributes into one.
► Helium impurities accumulating on Si planes weaken the cohesion between Si–Ti layers in Ti3SiC2.
► He–vacancy complexes will grow up in the form of tabular configuration along Si layers.
► Helium intensifies the delamination of Ti3SiC2 and degrades its mechanical properties.