MECHANICAL MATERIAL TESTS BY THE NANOINDENTATION METHOD AT VARIOUS INDENTER AND SPECIMEN TEMPERATURES

Theoretical and experimental studies have been made of the nonisothermal contact interaction of an unsharpened conical indenter and an elastic material with an inhomogeneous surface layer. A relevant contact problem of thermoelasticity with arbitrarily changed thermomechanical characteristics in the depth of the surface layer has been formulated. To solve the boundary-value problem, the apparatus of integral Hankel transforms is used. With the use of the asymptotic method, a numerical-analytical approximated solution of the problem has been constructed, the values of the corresponding heat fl ux and of the half-space surface displacement have been determined, and the values of contact stresses beneath the die have been found. The developed model is used to estimate the value of indenter displacement caused by the thermoelastic deformation of the specimen. The results of the experiment on nonisothermal indentation of the prepared specimen of steel 40Kh on a Nanotest 600 facility are presented. The application of nanoindentation for investigations of mechanical properties of materials at high temperatures is discussed.
   
Author:  L. I. Krenev, S. S. Volkov, E. V. Sadyrin, T. I. Zubar, and S. A. Chizhik
Keywords:  nanoindentation, heating, nonisothermal contact, contact problem, mathematical modeling
Page:  594