Influence of temperature, strain rate, and loading direction on the mechanical properties of D022-TiAl3: Insights from molecular dynamics simulations

TL Nguyen and AV Pham and V Nguyen and HP Nguyen and XT Nguyen and TC Cheng, MATERIALS TODAY COMMUNICATIONS, 46, 112875 (2025).

DOI: 10.1016/j.mtcomm.2025.112875

Molecular Dynamics (MD) simulations are pivotal in investigating the dynamic behavior, thermodynamic properties, and mechanical characteristics of materials. This study investigates the deformation properties of single crystal D022-TiAl3 using MD simulations under uniaxial tensile loading, with a focus on the effects of temperature, strain rate, and loading direction. The D022-TiAl3 structure, modeled using a body-centered tetragonal (BCT) unit cell, was subjected to simulations at temperatures ranging from 300 K to 1373 K, various strain rates (1 x108 to 5 x10 10 s-1), and different loading directions (1 0 0, 0 0 1, and 1 0 1). The results reveal significant temperature dependence, showing a decrease in tensile strength, Young's modulus, and flow stress with increasing temperature, along with pronounced phase transitions and dislocation movement at higher temperatures. At lower temperatures, the material exhibited brittle behavior, while increased ductility was observed at elevated temperatures. The study also explored the influence of strain rate on the deformation mechanisms, finding that higher strain rates lead to increased tensile strength and reduced amorphous regions, with dislocation networks becoming denser and more distributed. Additionally, the material's mechanical response was found to exhibit significant anisotropy due to the asymmetry of the BCT lattice, with different behavior observed along the different loading directions. The 1 0 0 direction showed the highest yield strain but lower tensile strength and stiffness, while the 0 0 1 direction exhibited superior tensile strength, Young's modulus, and structural stability. In contrast, the 1 0 1 direction displayed the lowest yield strain and tensile strength due to rapid dislocation saturation and strain localization. These findings highlight the potential of D022-TiAl3 for high-temperature structural applications in aerospace and automotive industries, where its combination of strength, stability, and oxidation resistance can contribute to improved performance and durability of critical components.

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