Design of functionally graded Ti–Al alloy with adjustable mechanical properties: a molecular dynamics insights

Gao, Yue; Xie, Quan; Gao, Tinghong; Yang, Wensheng; Chen, Qian; Tian, Zean; Li, Lianxin; Liang, Yongchao; Wang, Bei

doi:10.1016/j.jmrt.2023.01.016

Cited by 6 publications

(1 citation statement)

References 57 publications

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“…The interatomic interactions in the Ti–Al system are modeled using the embedded atom model (EAM) potential developed in ref by fitting to both experimental and ab initio data. This potential model has proven to be effective in various investigations and has been successfully tested for many mechanical and structural-energy properties of Ti–Al systems. ,− A recent comprehensive study has demonstrated that after over two decades since its creation, this potential model remains a highly effective representation of the physical properties of the Ti–Al systems, even compared to newer models. , …”

Section: Methodsmentioning

confidence: 99%

Elucidating Interfacial Dynamics of Ti–Al Systems Using Molecular Dynamics Simulation and Markov State Modeling

Li,

Tian,

Moridi

et al. 2023

ACS Appl. Mater. Interfaces

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Due to their remarkable mechanical and chemical properties, Ti–Al-based materials are attracting considerable interest in numerous fields of engineering, such as automotive, aerospace, and defense. With their low density, high strength, and resistance to corrosion and oxidation, these intermetallic alloys and metal-compound composites have found diverse applications. However, additive manufacturing and heat treatment of Ti–Al alloys frequently lead to brittleness and severe formation of defects. The present study delves into the interfacial dynamics of these Ti–Al systems, particularly focusing on the behavior of Ti and Al atoms in the presence of TiAl3 grain boundaries under experimental heat treatment conditions. Using a combination of molecular dynamics and Markov state modeling, we scrutinize the kinetic processes involved in the formation of TiAl3. The molecular dynamics simulation indicates that at the early stage of heat treatment, the predominating process is the diffusion of Al atoms toward the Ti surface through the TiAl3 grain boundaries. Markov state modeling identifies three distinct dynamic states of Al atoms within the Ti/Al mixture that forms during the process, each exhibiting a unique spatial distribution. Using transition time scales as a qualitative measure of the rapidness of the dynamics, it is observed that the Al dynamics is significantly less rapid near the Ti surface compared to the Al surface. Put together, the results offer a comprehensive understanding of the interfacial dynamics and reveal a three-stage diffusion mechanism. The process initiates with the premelting of Al, proceeds with the prevalent diffusion of Al atoms toward the Ti surface, and eventually ceases as the Ti concentration within the mixture progressively increases. The insights gained from this study could contribute significantly to the control and optimization of manufacturing processes for these high-performing Ti–Al-based materials.

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