The role of γ/γ interfacial spacing on the tensile behavior in lamellar TiAl alloy via molecular dynamics simulations

X Zhou and SP Wang and ZT Lu and XG Huang and XB Feng and JY Fu and WJ Li and PC Zhai and GD Li, ACTA MECHANICA SINICA, 41, 124030 (2025).

DOI: 10.1007/s10409-024-24030-x

The lamellar microstructure is one of the most typical microstructures of TiAl alloys. There are three gamma/gamma interfaces with different microstructures in lamellar gamma-TiAl alloys. In this work, we investigated the deformation processes of lamellar gamma-TiAl alloys with different interfacial spacing (lambda) via uniaxial tensile loading using molecular dynamics simulations, including true twin (TT), pseudo- twin (PT), rotational boundary (RB), and the mixed structure (TT parallel to PT parallel to RB). The results show that in all lamellar gamma-TiAl samples, the Shockley partial dislocation prefers to nucleate in the region between two neighboring interfaces. Then, dislocations move towards, crossing the gamma/gamma interface. Finally, the dislocation slippage leads to the destruction of the interface, resulting in cracks and structural failure. With the decrease of lambda, the ultimate strength slightly increases in the TT or PT structure of gamma-TiAl, which follows the Hall-Petch relation. But in general, the interfacial spacing has a slight effect on the ultimate strengths of these four structures of gamma-TiAl.

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