Micromechanism of Cold Deformation of Two-Phase Polycrystalline Ti-Al Alloy with Void

RC Feng and MM Wang and HY Li and YN Qi and Q Wang and ZY Rui, MATERIALS, 12, 184 (2019).

DOI: 10.3390/ma12010184

Cold deformation behavior of polycrystalline metallic material is affected by intrinsic defects such as dislocations, voids, inclusions etc. Existing studies on alpha(2)(Ti3Al) + gamma(TiAl) two-phase Ti Al alloy cover about deformation behavior mainly on macro scale. This paper focuses on the cold deformation mechanism of two-phase Ti Al alloy at micro scale, and the role of voids in deformation process. Molecular dynamics simulations were performed to study the evolution of micro structure of material under uniaxial tension. Interaction between spherical nano voids with different size and position was also examined in the simulation. The results show that (1) In elastic stage, deformation of the two-phase is coordinated, but Ti3Al is more deformable; (2) In plastic stage, gamma phase is the major dislocation source in two-phase alloy; (3) voids detracts the strength of the two- phase alloy, while the position of void affect the degree of this subtraction, voids located at the boundary of alpha(2)/gamma phase have significant detraction to strength.

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