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Abstract

Molecular dynamics simulations are an excellent tool for understanding crack-tip interactions in interface-dominated microstructures, but the simulation setup can affect the predicted behavior as there are many degrees of freedom. To shed light on this and at the same time to understand the impact of the specific interface structure, a systematic study of crack-tip interface interactions in nano-lamellar two-phase TiAl was carried out. To separate microstructure and crack geometry influences, the type of interface, crack configuration, and loading direction were varied in these simulations. Results show that the semicoherent 𝛾-pseudo twin interface is the strongest barrier for the crack propagation while the coherent true twin interface is the weakest. The analysis of the contributing factors shows, that the crack orientation has more influence on the crack evolution than the crack aspect ratio. The effect of the individual interfaces can be quantified by calculating their shielding effects, but as it turns out this effect is strongly dependent on the crack configuration. However, regardless of the crack configurations, the coherent true twin interface appears to be the most effective interface in terms of shielding.