The correlation of the indentation size effect measured with indenters of various shapes

• Published in: Journal of the mechanics and physics of solids 2002-04, Vol.50 (4), p.681-694
• Main Authors: Swadener, J.G., George, E.P., Pharr, G.M.
• Format: Article
• Language: English
• Subjects: A. Dislocations; C. Mechanical testing; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Indentation and hardness; Measurement and testing methods; Measurement methods and techniques in continuum mechanics of solids; Mechanical contact (friction...); Physics; Solid mechanics; Strengthening and mechanisms; Structural and continuum mechanics; Tribology and mechanical contacts
• ISSN: 0022-5096
• DOI: 10.1016/S0022-5096(01)00103-X

Experimental results are presented which show that the indentation size effect for pyramidal and spherical indenters can be correlated. For a pyramidal indenter, the hardness measured in crystalline materials usually increases with decreasing depth of penetration, which is known as the indentation size effect. Spherical indentation also shows an indentation size effect. However, for a spherical indenter, hardness is not affected by depth, but increases with decreasing sphere radius. The correlation for pyramidal and spherical indenter shapes is based on geometrically necessary dislocations and work-hardening. The Nix and Gao indentation size effect model (J. Mech. Phys. Solids 46 (1998) 411) for conical indenters is extended to indenters of various shapes and compared to the experimental results.