Abstract
The purpose of this paper is to investigate the effects of parameters like loading, unloading rates, and dwell period on the depth-sensing indentation properties is. A bowing out or nose is the most common behavior for polymeric materials in nanoindentation tests due to the viscoelastic behavior. This leads to the negative slope and consequently, significant errors in the calculations of hardness and elastic modulus values using depth-sensing indentation techniques. A common practice to minimize this effect if to apply a creep at maximum indentation load or increase the unloading rates as considered in this work. The results showed that these parameters have significant impact on the nanoindentation hardness and elastic modulus. The hardness and elastic modulus increase with increasing the loading rate during nanoindentation testing. The elastic modulus values reduce significantly by increasing the unloading rate. Contrarily, hardness increase with increasing the unloading rate. Hardness and elastic modulus values are significantly affected by increasing the dwell period. The hardness reduces by 20% after increasing creep time and elastic modulus increases with increasing the dwell time. (C) 2020 The Authors. Published by IASE.