Impact of phase/grain boundary on tensile properties and dynamic deformation mechanisms of duplex fully lamellar TiAl polycrystalline

M Zheng and XB Dai and DF Qu and Q Lu and WH Chen and XC Wei and DL Luo and ZX Zhu, JOURNAL OF ALLOYS AND COMPOUNDS, 1039, 183111 (2025).

DOI: 10.1016/j.jallcom.2025.183111

Phase/grain boundary plays a crucial role in the plastic deformation mechanism and strengthening effect of TiAl alloys. This paper systematically investigates the influence of phase/grain boundary coupling on the mechanical properties and microstructural evolution of duplex fully lamellar TiAl polycrystalline (DFL-TiAl-PC) during triaxial synchronous stretching based on molecular dynamics (MD) simulations. The results show that compared with gamma-TiAl polycrystalline (gamma-TiAl- PC), DFL-TiAl-PC exhibits higher yield strength, toughness, and ductility, but these properties decrease with increasing temperature, this stems from the phase boundary's hindering effect on dislocation movement. In the initial stage of plastic deformation, high shear strain and dislocation density are concentrated in the phase/grain boundary region, when the temperature rises, the aggregation of dislocations in this region increases significantly. Under the same conditions, the phase boundary formed by the ordered stacking of the gamma phase and the alpha 2 phase can effectively inhibit grain boundary slip, resulting in a significantly lower tendency for pore formation in DFL-TiAl-PC than in gamma-TiAl-PC.

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