Quantitative approach to determine the mechanical properties by nanoindentation test: Application on sandblasted materials

• A method for determination of macrohardness from nanoindentation test is introduced.
• Four sandblasted 2017A samples with different roughness are studied by the method.
• The effect of surface roughness on the scatter of nanoindentation curves is estimated.

A novel method is developed to improve the accuracy in determining the mechanical properties from nanoindentation curves. The key point of this method is the simultaneous statistical treatment of several loading curves to correct the zero point error and identify the material properties considering size effects. The method is applied to four sandblasted aluminum-based specimens with different surface roughness. A linear relationship is obtained between the standard deviation of the initial contact error and the roughness which highlights the effect of the surface roughness on the reproducibility of the indentation curves. Moreover, the smaller standard deviation of the hardness given by the method confirms the importance of considering the initial contact error for an accurate determination of the material properties.