The reaction mechanism and interfacial crystallization of Al nanoparticle-embedded Ni under shock loading

YF Xie and JL Shao and R Liu and PW Chen, DEFENCE TECHNOLOGY, 33, 114-124 (2024).

DOI: 10.1016/j.dt.2023.05.021

The shock -induced reaction mechanism and characteristics of Ni/Al system, considering an Al nanoparticle-embedded Ni single crystal, are investigated through molecular dynamics simulation. For the shock melting of Al nanoparticle, interfacial crystallization and dissolution are the main characteristics. The reaction degree of Al particle first increases linearly and then logarithmically with time driven by rapid mechanical mixing and following dissolution. The reaction rate increases with the decrease of particle diameter, however, the reaction is seriously hindered by interfacial crystallization when the diameter is lower than 9 nm in our simulations. Meanwhile, we found a negative exponential growth in the fraction of crystallized Al atoms, and the crystallinity of B 2-NiAl (up to 20%) is positively correlated with the speci fic surface area of Al particle. This can be attributed to the formation mechanism of B 2 -NiAl by structural evolution of finite mixing layer near the collapsed interface. For shock melting of both Al particle and Ni matrix, the liquid -liquid phase inter -diffusion is the main reaction mechanism that can be enhanced by the formation of internal jet. In addition, the enhanced diffusion is manifested in the logarithmic growth law of mean square displacement, which results in an almost constant reaction rate similar to the mechanical mixing process.
(c) 2023 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Return to Publications page