Size effect of indenter on determining modulus of nanowires using nanoindentation technique

This study uses a finite element modeling to simulate the behavior of copper nanowires submitted to nanoindentation and estimate their mechanical properties. The simulation results reveal that using the well-known Oliver-Pharr theory, generally applied for materials with semi-infinite half-space, yields an underestimate elastic modulus of the wire materials. Moreover, the radius of the indenter tip also influences the accuracy of the predicted elastic modulus. Such errors are mainly from the overestimate of the contact area between the indenter and the specimen. They can be corrected from the numerical modeling. The elastic modulus of the wires calculated from the corrected contact area is highly close to the bulk value.