Exploring the Effect of Aluminium Solute Atoms on Nanomechanical Properties of Copper‐Aluminium System using Nanoindentation

In this work, nanomechanical properties for Cu and Cu–Al (where Al = 2, 4, 6, and 8 wt%) alloys are determined using nanoindentation with Berkovich tip. Nanoindentation experiments are performed using trapezoidal load function where maximum load ( P _m ) varies from 1000 to 9000 μN at an equal interval of 1000 μN by maintaining equal loading and unloading rate. It is found that Cu8Al sample shows lower depth of penetration ( h ) at any load ( P ) in comparison to other samples due to more pinning of dislocations or hinderance of the dislocation movement by solute (Al) atoms during nanoindentation deformation. In addition, it is observed that the recovery is maximum for Cu8Al sample among all samples; however, this recovery is reducing with the increasing P _m for all samples. Thereafter, the elasticity and plasticity index are calculated from the area under the P – h curves, which shows that the elastic index is maximum for Cu8Al and minimum for Cu. Furthermore, the nanomechanical properties (reduced elastic modulus [ E _r ] and hardness [ H ]) are reported for all samples and significant indentation size effect is observed for Cu8Al due to dislocation structure during deformation.