Deformation Mechanism of Solidified Ti3Al Alloys with Penta Twins under Shear Loading

Abstract

Owing to the excellent mechanical properties of the Ti3Al alloy, the study of its microstructure has attracted the extensive attention of researchers. In this study, a Ti3Al alloy was grown based on molecular dynamics using a decahedral precursor. Face centered cubic nanocrystals with tetrahedral shapes were formed and connected by twin boundaries (TBs) to form penta twins. To understand the shear response of the Ti3Al alloy with multiple and penta twins, a shear load perpendicular to the Z-axis was applied to the quenched sample. The TBs slipped as Shockley dislocations commenced and propagated under shear loading, causing the detwinning of the penta twins and the failure of the system, indicating that the plastic deformation had been due to Shockley dislocations. The slip mechanism of multi-twinned structures in the Ti3Al alloy is discussed in detail. This study would serve as a useful guide for the design and development of advanced alloy materials.