Cylinder indenter size effect in Nanoindentation test

The initial plastic deformation of single crystal aluminium was simulated to study the indentation size effect in the nanoindentation test by using quasicontinuum method.The feature of elastic and initial plastic deformation in the indentation tests in case of rigid cylinder indenters with different diameter was investigated.The corresponding load-depth curves were obtained.The nanohardness and elastic modulus were estimated based on the Oliver-Pharrmethod.The simulated results show that nanohardness decreases significantly with the increase of the indenter size,i.e.,there exists strong indentation size effect on nanohardness.However,the size effect phenomenon vanishes for a larger indenter size more than 80Å.The results also show that size effect on elastic modulus may be ignored.It indicates that the elastic modulus is dependent on the binding energy of the atoms,whereas it is independent on the indenter size.