Finite element studies of the influence of pile-up on the analysis of nanoindentation data
- Rice Univ., Houston, TX (United States). Dept. of Materials Science
- Nano Instruments, Inc., Oak Ridge, TN (United States)
Methods currently used for analyzing nanoindentation load-displacement data give good predictions of the contact area in the case of hard materials, but can underestimate the contact area by as much as 40% for soft materials which do not work harden. This underestimation results from the pile-up which forms around the hardness impression and leads to potentially significant errors in the measurement of hardness and elastic modulus. Finite element simulations of conical indentation for a wide range of elastic-plastic materials are presented which define the conditions under which pile-up is significant and determine the magnitude of the errors in hardness and modulus which may occur if pile-up is ignored. It is shown that the materials in which pile-up is not an important factor can be experimentally identified from the ratio of the final depth after unloading to the depth of the indentation at peak load, a parameter which also correlates with the hardness-to-modulus ratio.
- Research Organization:
- Oak Ridge National Lab., TN (United States); Oak Ridge Associated Universities, Inc., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464; AC05-76OR00033
- OSTI ID:
- 230353
- Report Number(s):
- CONF-960401--17; ON: DE96009403
- Country of Publication:
- United States
- Language:
- English
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