Probing the mechanical and deformation behaviour of CNT-reinforced AlCoCrFeNi high-entropy alloy – a molecular dynamics approach

This present study investigates the mechanical and deformation behaviour of pristine and carbon nanotube (CNT)-reinforced AlCoCrFeNi high-entropy alloys (HEAs) using molecular dynamics (MD) simulations. The results reveal that an increase in the atomic fraction of Al in pristine AlCoCrFeNi HEAs leads to reduced mechanical behaviour. The mechanical behaviour of the pristine AlCoCrFeNi HEAs notably improves following CNT reinforcement, particularly when using CNT with higher chirality. As the chirality of the CNT increases from (6,6) to (15,15), Young's modulus, yield stress, and toughness of the (15,15) CNT-Al20CoCrFeNi HEA enhance by 17.34%, 29.44%, and 44.44% compared to the (6,6) CNT – Al20CoCrFeNi HEA. HEAs with lower Al fractions experience more substantial stress drops due to rapid structural changes. CNT reinforcement, particularly with higher chirality, decelerates this structural transformation, enhancing yield strength greatly. The analysis of the dislocation evolution revealed that the CNT-reinforced HEA exhibits higher dislocation density compared to the pristine HEA, indicating strain hardening from CNT reinforcement. Furthermore, examination of atomic shear strain reveals confined deformation along shear bands in CNT-reinforced HEAs, leading to the deformation and eventual fracture of CNTs. This study provides valuable insights for enhancing the mechanical behaviour of CNT-reinforced AlCoCrFeNi HEAs, aiding in their design and development.