Nanoindentation in materials research: Past, present, and future

The method we introduced in 1992 for measuring hardness and elastic modulus by nanoindentation testing has been widely adopted and used in the characterization of mechanical behavior at small scales. Since its original development, the method has undergone numerous refinements and changes brought about by improvements to testing equipment and techniques, as well as advances in our understanding of the mechanics of elastic-plastic contact. In this article, we briefly review the history of the method, comment on its capabilities and limitations, and discuss some of the emerging areas in materials research where it has played, or promises to play, an important role.