Study of analysis methods of depth-sensing indentation test data for spherical indenters

The underlying theory behind the extraction of elastic modulus and hardness from the unloading load-displacement data obtained with a spherical indenter was explored in detail. A formal treatment of the effect of indenter elasticity was given, and the validity of the use of the reduced or combined modulus in analytical treatments was verified. The "Oliver and Pharr" method and the "Field and Swain" methods of analyses were compared in detail and shown to be equivalent.