Determining the Constitutive Properties of Sintered Nano Silver via Reverse Analysis and Nanoindentation

Nanoindentation testing technology can effectively and conveniently evaluate the mechanical properties of materials at the micro- and nano-scales. However, the nanoindentation test is a nonlinear mechanical process, which is difficult to determine the elastic–plastic constitutive parameters of the indentation material via analytical solution. It is important to mastering these constitutive parameters for the application of the materials at micro and nano scales. In this study, a reverse analysis method for determining elastic–plastic constitutive properties of metallic materials is proposed via the dimensional analysis and finite element (FE) simulation. The dimensionless function including the yield stress (σy) and strain hardening exponent (n) is firstly constructed via the dimensional analysis method. After assuming a reasonable the n value, the constitutive properties are determined via constructing the dimensionless function to solve the σy value and the FE simulations are carried out. By adjusting the n value until the simulated unloading curve is agreement with the experimental curve we can determines the n of the materials. Next the σy of the materials is obtained accurately and solely via the dimensionless function and modified simulation. Finally, nanoindentation experiments were conducted with sintered nano-silver to verify the accuracy and effectiveness of the method.