Creep correction of elastic modulus and hardness for viscoelastic <scp>materials during</scp> microindentation
Erqiang Liu, Lingyu Kong, Gesheng Xiao, Jinbao Lin, Guanghui Zhao, Huaying Li
Abstract
In this paper, a dimensionless creep correction factor is proposed to simplify the calculation by using a fitting function of creep displacement combined with reduced modulus formula. Using experimental results of PA12 under different testing conditions during indentation, the creep‐corrected calculations of contact depth, reduced modulus, and hardness are studied. Results show that the elastic modulus without creep correction is significantly over‐estimated, while the creep‐corrected elastic modulus is a constant value (1.25 GPa) which does not change with the test variables. Conversely, the nanohardness extracted by the conventional approach is under‐estimated and the creep‐corrected contact hardness is not constant due to the time‐dependent deformation. The introduction of creep correction factor can significantly simplify the correction calculation process of material parameters.