Influencing mechanism of nanoscale He bubbles on the crack propagation in TiT_1.75 under tension

This work investigates the influence of the pre-existing He bubble on the crack propagation in TiT_1.75 with molecular dynamic simulations. Under high strain rate tension, TiT_1.75 exhibits typical brittle fracture characteristics with low fracture toughness at the microscopic scale, and the crack propagation path approximately follows the (111) plane with normal stretching direction. However, the presence of He bubble may change the stress concentration near the crack tip, resulting in the bending and even branching of cracks. The position relationship between He bubbles and crack tips is discussed, and the variation of the tensile strength with the distance and the angle is revealed. The total length and pattern of crack propagation are also presented. It is found that the tensile strength approximately linearly decreases with the He bubble concentrations, and the self-expansion and coalescence of He bubbles will gradually dominate the fracture process.