Abstract
Indentation tests are used widely to assess mechanical properties of materials such as hardness, strength and fracture toughness. More recently, indentation has been used to explore phenomena such as strain gradient plasticity and creep. The parameters of the deformation field, e.g., strain rate, strain and strain gradient; in plane strain indentation of metals with a wedge and flat punch is measured in situ using a Particle Image Velocimetry technique. The formation of shear bands, dependence of strain rate on indenter velocity and scaling of deformation field are characterized explicitly. These results are analyzed in the context of prior descriptions of the field obtained from indirect measurements using observation of flow lines, metallographic features and grid deformation. Lastly, slip line fields for plane strain indentation are derived from the measured deformation fields and compared with those proposed by Prandtl. ©2008 Society for Experimental Mechanics Inc.