Atomic-scale insights into the effect of interlayer spacing on the tensile mechanical properties of Ti-TiAl laminated composites

Q Zhu and Z Zhang and M Chen and LF Zhang and K Liu and GH Fan and P Zhang, MATERIALS TODAY COMMUNICATIONS, 45, 112381 (2025).

DOI: 10.1016/j.mtcomm.2025.112381

Titanium aluminide (TiAl) alloys are ideal for aerospace and automotive applications due to their low density, high specific strength, and excellent high-temperature performance, but their inherent brittleness at room temperature limits widespread adoption. To enhance the ductility and overall mechanical performance of TiAl alloys, Ti/TiAl laminated composites (LMCs) have been developed by alternately stacking layers of Ti and TiAl. This study employs molecular dynamics (MD) simulations to investigate the impact of interlayer spacing on the tensile mechanical properties of Ti/TiAl LMCs at the atomic scale. Models with interlayer spacings of 4 nm, 8 nm, and 16 nm were constructed and subjected to uniaxial tensile deformation. The results reveal a nonlinear relationship between interlayer spacing and mechanical properties: yield stress increases marginally with spacing, while the average flow stress peaks at an interlayer spacing of 8 nm, with a 12.1 % improvement over the 4 nm spacing. Smaller spacings (4 nm) lead significant strain and stress concentrations, particularly in the TiAl phase, resulting to localized necking and early failure. In contrast, larger spacings (16 nm) maintain nearly planar interfaces but reduce the strengthening effects due to the smaller interfacial area. The 8 nm interlayer spacing demonstrates an optimal balance, enhancing both strength and plasticity by effectively distributing stress and accommodating dislocation activity. These findings provide critical insights for optimizing the layered structure of Ti/TiAl LMCs, offering pathways to improve their mechanical performance for high-performance engineering applications.

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