Theoretical investigation on helium incorporation in Ti3AlC2

Xiao, Jingren; Wang, Chenxu; Yang, Tonghai; Kong, Shuyan; Xue, Jianming; Wang, Yugang

doi:10.1016/j.nimb.2013.04.006

Cited by 28 publications

(16 citation statements)

References 41 publications

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“…For the fully relaxed Ti 3 AlC 2 structure, we obtain the lattice constants of a = 3.082 Å and c = 18.652 Å, in good agreement with the findings of the previous studies. 12,14 To determine the most stable site for a single He atom in perfect or defective Ti 3 AlC 2 , we calculate the solution energy for a He atom at different sites. The solution energy for a He atom in Ti 3 AlC 2 with and without a vacancy is defined as 22,23…”

Section: Resultsmentioning

confidence: 99%

New insight into the helium-induced damage in MAX phase Ti3AlC2 by first-principles studies

Bai

Zha

et al. 2015

The Journal of Chemical Physics

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In the present work, the behavior of He in the MAX phase Ti 3 AlC 2 material is investigated using first-principle methods. It is found that, according to the predicted formation energies, a single He atom favors residing near the Al plane in Ti 3 AlC 2 . The results also show that Al vacancies are better able to trap He atoms than either Ti or C vacancies. The formation energies for the secondary vacancy defects near an Al vacancy or a C vacancy are strongly influenced by He impurity content. According to the present results, the existence of trapped He atoms in primary Al vacancy can promote secondary vacancy formation and the He bubble trapped by Al vacancies has a higher tendency to grow in the Al plane of Ti 3 AlC 2 . The diffusion of He in Ti 3 AlC 2 is also investigated. The energy barriers are approximately 2.980 eV and 0.294 eV along the c-axis and in the ab plane, respectively, which means that He atoms exhibit faster migration parallel to the Al plane. Hence, the formation of platelet-like bubbles nucleated from the Al vacancies is favored both energetically and kinetically. Our calculations also show that the conventional spherical bubbles may be originated from He atoms trapped by C vacancies. Taken together, these results are able to explain the observed formation of bubbles in various shapes in recent experiments. This study is expected to provide new insight into the behaviors of MAX phases under irradiation from electronic structure level in order to improve the design of MAX phase based materials. C 2015 AIP Publishing LLC. [http://dx

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Section: Resultsmentioning

confidence: 99%

New insight into the helium-induced damage in MAX phase Ti3AlC2 by first-principles studies

Bai

Zha

et al. 2015

The Journal of Chemical Physics

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“…It is important to note that, in contrast to neutrons, which pass through the bulk, the penetration depth of heavy ion a nd He irradiation is limited t o t he s ubsurface, a nd H e a toms t end to a ccumulate a nd f orm bubbles inside the material after momentum transfer. This has been illustrated by Xiao et al via ab initio methods, showing the He most energetically favors Al-site interstitials in Ti 3 AlC 2 [22]. More recently, Wang et al irradiated Ti 3 AlC 2 samples with 50 keV He ions with fluences ranging from 8×10 16 cm -2 to 1×10 18 cm -2 , resulting in the formation of spherical He bubbles, string-like bubbles and faulting zones [23].…”

Section: Introductionmentioning

confidence: 93%

Effect of neutron irradiation on select MAX phases

et al. 2015

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Herein we report on the effect of neutron irradiation-of up to 0.1 displacements per atom at 360(20)°C or 695(25)°C-on polycrystalline samples o f Ti 3 AlC 2 , Ti 2 AlC, Ti 3 SiC 2 and Ti 2 AlN. X-ray diffraction refinement of the irradiated samples showed irradiation-enhanced dissociation into TiC of the Ti 3 AlC 2 and Ti 3 SiC 2 phases, most prominently in the former. Ti 2 AlN also showed an increase in TiN content, as well as Ti 4 AlN 3 after irradiation. In contrast, Ti 2 AlC was quite stable under these irradiation conditions. Dislocation loops a re seen t o f orm in T i 2 AlC a nd Ti 3 AlC 2 after ir radiation at 360(20)°C. The room temperature electrical r esistivity of al l samples i ncreased by an or der of magnitude after irradiation at 360(20)°C, but onl y by 25% after 695(25)°C, providing e vidence for t he MA X pha ses' dy namic recovery at temperatures as low at 695(25)°C. Based on these preliminary results, it appears that Ti 2 AlC and Ti 3 SiC 2 are the more promising materials for high-temperature nuclear applications.

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“…• Class IV: theoretical calculations on non-metallic compounds [212][213][214][215][216][217][218][219][220][221][222][223][224].…”

Section: Statistical Detailsmentioning

confidence: 99%

“…They are mainly focused on binary or ternary compounds: SiC [215,218], UC [216], β-ErH2 [219], UO2 [220], ZrSiO4 [221], Ti3AlC2 [223], and more scarcely to complex substrate such as sodalite (Na8Al6Si6O24Cl2) [213] or nanostructured materials such as metal/oxide interface [222].…”

Section: Class III and Iv: Theoretical Calculations On Metallic And mentioning

confidence: 99%