Effects of uniaxial stress and temperature on the interfacial tensile strength and stability of Al/NiO nanolaminates: A first-principles study

Abstract

Nanoenergetic multilayer films have been widely prepared due to their unique advantages in realizing “nanoenergetics-on-a-chip”. Recently, the potential for adjusting the performance of nanothermites without altering their film thickness has attracted much attention, prompting researchers to concentrate on film stress. Here, we employed first-principles tensile tests and ab initio molecular dynamics simulations to investigate the tensile properties, fracture mechanisms, and film stability of two Al/NiO interfaces under pre-stress. An analysis of electron localization function and bond overlap population shows that the weakest locations of the (100)-Top and (111)-Top interface systems are distinctly different, leading to two different fracture mechanisms. When the pre-stress and temperature are coupled, the reactivity of Al/NiO as an energetic material is enhanced. Particularly for (111)-Top, the amorphous, mixed region between the two phases replaces the original coherent interface. With the increase of the pre-stress, the crack evolves ahead of the critical strain, indicating that the coupling effects of the pre-stress and temperature have an important influence on the stability and fracture strength. This work not only reveals the mechanical properties of Al/NiO, but also provides a theoretical guidance for optimizing the structure of energetic nanolaminates.