Analysis of deformation behaviour of Al-Ni-Co thin film coated aluminium during nano-indentation: a molecular dynamics study

In the present work, molecular dynamics simulations of AlNiCo metallic film deposition on FCC Al substrate and subsequently nano-indentation on the same specimen considering different indenter velocities have been performed using Embedded Atom Method (EAM) potential. The mechanical properties and deformation behaviour of AlNiCo thin film deposited Al substrate is investigated subjected to simulated nano-indentation test. It has been found that indenter velocity significantly influences the calculated hardness of the thin film coated substrate specimen and faster indentation process increases the hardness of the specimen. This finding has been rationalised by correlating with the generation of various full and partial dislocations and their interactions during the nano-indentation process. Sessile dislocations such as stair-rod and Frank partials are found to aid/help the strain hardening phenomena. Furthermore, the effect of indenter velocity on the pile-up formation during the nano-indentation process is also investigated here and it is observed that the amount of pile-up reduces as indenter velocity increases.