Reactivity of the Ti–Al system: Experimental study and molecular dynamics simulations

Bizot, Quentin; Politano, O.; Непапушев, А. А.; Вадченко, С. Г.; Рогачев, А. С.; Baras, F.

doi:10.1063/5.0004550

Cited by 14 publications

(7 citation statements)

References 27 publications

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“…The influence of vacancies in this case is explained by the fact that diffusion under a solid-phase contact did not take place at all without any other defects with the given IPB orientation. This was also noted by the authors of [18], who explained it by high similarity of the atomic planes (0001) in Ti and (111) in Al (distances between the nearest atoms in these planes are very close for both metals: 2.951 and 2.864 Å at absolute zero respectively; this difference becomes even smaller under heating).…”

Section: Solid-phase Contact On the Ti−al Boundarysupporting

confidence: 72%

Influence of the orientation of Ti-Al interphase boundary on the mutual diffusion rate at the solid and liquid states of aluminium: molecular dynamics simulation

Полетаев

Rakitin

2022

Physics of the Solid State

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The influence of the orientation of Ti-Al interphase boundary on the intensity of mutual diffusion at solid-phase and solid-liquid-phase contacts was studied by the method of molecular dynamics. Four orientations of the boundary with respect to the Ti (hcp) and Al (fcc) lattices were considered: (0001) : (111), (0001) : (001), (1010) : (111), (1011) : (001). At solid-phase contact, an important phenomenon influencing the intensity of mutual diffusion was the formation, due to the mismatch of the lattices of Ti and Al, of grain boundaries in Al parallel to the interphase boundary. This boundary was both the main source and sink of structural defects, including vacancies required for diffusion to proceed. In the case of solid-liquid-phase contact, after melting of aluminium, part of it near the interphase boundary remained in the crystalline state, repeating the titanium lattice. That is, the boundary between the crystal and the liquid metal was shifted by two or three atomic planes deep into the aluminium. For the considered orientations, concentration curves were obtained after simulating mutual diffusion at different temperatures. The flatter parts of the curves, which are responsible for the diffusion of Ti atoms deep into liquid Al, turned out to be similar for all orientations. However, the parts related to the diffusion of Al atoms into crystalline Ti were different: diffusion of Al atoms in Ti proceeded more intensively with the orientation of the boundary (0001) and more slowly with the orientations (1010) and (1011). Keywords: molecular dynamics, diffusion, interphase boundary, titan, aluminum.

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Section: Solid-phase Contact On the Ti−al Boundarysupporting

confidence: 72%

Influence of the orientation of Ti-Al interphase boundary on the mutual diffusion rate at the solid and liquid states of aluminium: molecular dynamics simulation

Полетаев

Rakitin

2022

Physics of the Solid State

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“…895.15 K is a typical temperature used in ref 9 Besides, multiple experimental studies show a temperature range of 825− 1220 K for Ti/Al system heat treatment. 14,9,10,31,32 2.2. Markov State Modeling Methods.…”

Section: Molecular Simulation Detailsmentioning

confidence: 99%

“…11−13 Moreover, a recent MD study combined with experiments on the reactivity of the Ti−Al system has identified an exothermic atom substitution process at the Ti/Al interface, where liquid Al atoms replace solid Ti atoms, leading to continued dissolution from areas where multiple Ti atoms have been substituted in close proximity. 14 Another recent study used MD to investigate the self-diffusion in liquid and solid alloys of the Ti−Al system. The results show that the activation energy of self-diffusion depends on the concentration of components and is smaller in disordered alloys than in ordered alloys.…”

Section: Introductionmentioning

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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“…Indeed, the structural transformation hcp → fcc of Ti atoms has been observed in Ti-Al multilayers as a function of bilayer thickness and orientation at interfaces [45,46]. Nanometric Ti-Al multilayers can nevertheless be very stable in specific conditions: the interface between (002)-Ti plane and (111)-Al plane is very stable because of the slight misfit between the two structures [47]. In this case, the solubility of Ti in Al is very limited in the solid state.…”

Section: Study Of Deformationmentioning

confidence: 99%

Mechanical activation of metallic powders and reactivity of activated nanocomposites: a molecular dynamics approach

et al. 2021

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This work provides a description, at the atomic level, of a mechanical treatment on a mixture composed of two metallic powders. We used Molecular Dynamics to simulate the impact of grinding balls involving compaction and plastic deformation. Four binary mixtures were considered: Ni-Al, Ti-Al, Fe-Ni, and Fe-Cr, in order to assess the influence of the mechanical and structural properties of these pure elements on the characteristics of the activated mixture. The formation of nanometric mixing zones was tracked over deformation steps. The microstructure of the activated mixture was characterized using various indicators: local crystallographic configuration, radial distribution function, potential energy distribution, and mixing efficiency. The effects induced by the mechanical treatment were found to be specific for each binary system, and depended on both the mechanical and structural properties of the pure elements. Mechanical activation induces solid-state solubility, structural transformations, and defects. We also evaluated reactivity and transport properties at different temperatures in Ni-Al and Ti-Al nanocomposites fabricated by mechanical activation. We assessed the extent of their mixing zones, together with solubility, mobility, and the formation of intermetallics within these zones.

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Reactivity of the Ti–Al system: Experimental study and molecular dynamics simulations

Cited by 14 publications

References 27 publications

Influence of the orientation of Ti-Al interphase boundary on the mutual diffusion rate at the solid and liquid states of aluminium: molecular dynamics simulation

Influence of the orientation of Ti-Al interphase boundary on the mutual diffusion rate at the solid and liquid states of aluminium: molecular dynamics simulation

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

Mechanical activation of metallic powders and reactivity of activated nanocomposites: a molecular dynamics approach

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