The Design of Aluminum-Matrix Composites Reinforced with AlCoCrFeNi High-Entropy Alloy Nanoparticles by First-Principles Studies on the Properties of Interfaces

The present work reports the interfacial behaviors and mechanical properties of AlCoCrFeNi high-entropy alloy (HEA) reinforced aluminum matrix composites (AMCs) based on first-principles calculations. It is found the stability of HEA-reinforced AMCs is strongly dependent on the local chemical compositions in the interfacial regions, i.e., those regions containing more Ni atoms (>25%) or fewer Al atoms (<20%) render more stable interfaces in the HEA-reinforced AMCs. It is calculated that the interfacial energy of Al(001)/Al20Co19Cr19Fe19Ni19(001) interfaces varies from -0.242 eV/angstrom(2) to -0.192 eV/angstrom(2), suggesting that the formation of interfaces at (100) atomic plane is energetically favorable. For those constituent alloy elements presented at the interfaces, Ni could stabilize the interface whereas Al tends to deteriorate the stability of interface. It is determined that although the HEA-reinforced AMCs have less yield strength compared to aluminum, their Young's modulus is enhanced from 69 GPa for pure Al to 134 GPa. Meanwhile, the meaningful plasticity under tension could also be improved, which are related to the chemical compositions at the interfaces. The results presented in this work could facilitate the designs of compositions and interfacial behaviors of HEA-reinforced AMCs for structural applications.

Automated summary

The present study investigates the interfacial behaviors and mechanical properties of AlCoCrFeNi high-entropy alloy reinforced aluminum matrix composites (AMCs) through first-principles calculations. The stability of the HEA-reinforced AMCs is found to be strongly dependent on the chemical compositions in the interfacial regions. The interfacial energy of the Al(001)/Al20Co19Cr19Fe19Ni19(001) interfaces is calculated to vary, suggesting favorable formation of interfaces at the (100) atomic plane. Ni stabilizes the interface while Al deteriorates its stability. The HEA-reinforced AMCs show improved Young's modulus and meaningful plasticity under tension, which are related to the chemical compositions at the interfaces.