caa a22 4500 388021349 CHVBK 20180307124925.0 cr unu---uuuuu 161130e199802 xx s 000 0 eng 10.1557/JMR.1998.0055 doi S0884291400042928 pii (NATIONALLICENCE)cambridge-10.1557/JMR.1998.0055 Elastic loading and elastoplastic unloading from nanometer level indentations for modulus determinations [Elektronische Daten] A new method for evaluating modulus and hardness from nanoindentation load/ displacement curves is presented. As a spherical indenter penetrates an elastoplastic half-space, the elastic displacement above the contact line is presumed to diminish in proportion to the total elastic displacement under the indenter. Applying boundary conditions on the elastic and plastic displacements for elastic and rigid plastic contacts leads to an expression that can be best fit to the entire unloading curve to determine E*, the reduced modulus. Justification of the formulation is presented, followed by the results of a preliminary survey conducted on three predominantly isotropic materials: fused quartz, polycrystalline Al, and single crystal W. Diamond tips with radii ranging from 130 nm to 5 μm were used in combination with three different nanoindentation devices. Results indicate that the method gives property values consistent with accepted values for modulus and hardness. The importance of surface roughness and indentation depth are also considered. Copyright © Materials Research Society 1998 Gerberich W. W. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 Yu W. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 Kramer D. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 Strojny A. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 Bahr D. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 Lilleodden E. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 Nelson J. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 Journal of Materials Research Cambridge University Press 13/2(1998-02), 421-439 0884-2914 13:2<421 1998 13 JMR https://doi.org/10.1557/JMR.1998.0055 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/JMR.1998.0055 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gerberich W. W. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 NATIONALLICENCE 700 1- Yu W. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 NATIONALLICENCE 700 1- Kramer D. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 NATIONALLICENCE 700 1- Strojny A. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 NATIONALLICENCE 700 1- Bahr D. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 NATIONALLICENCE 700 1- Lilleodden E. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 NATIONALLICENCE 700 1- Nelson J. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 NATIONALLICENCE 773 0- Journal of Materials Research Cambridge University Press 13/2(1998-02), 421-439 0884-2914 13:2<421 1998 13 JMR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge