Measuring the elastic modulus and residual stress of freestanding thin films using nanoindentation techniques
- University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)
- Agilent Technologies, Oak Ridge, TN
- Sandia National Laboratory (SNL)
- ORNL
A new method is proposed to determine the elastic modulus and residual stress of freestanding thin films based on nanoindentation techniques. The experimentally measured stiffness-displacement response is applied to a simple membrane model that assumes the film deformation is dominated by stretching as opposed to bending. Dimensional analysis is used to identify appropriate limitations of the proposed model. Experimental verification of the method is demonstrated for Al/0.5 wt% Cu films nominally 22 {micro}m wide, 0.55 {micro}m thick, and 150, 300, and 500 {micro}m long. The estimated modulus for the four freestanding films match the value measured by electrostatic techniques to within 2%, and the residual stress to within 19.1%. The difference in residual stress can be completely accounted for by thermal expansion and a modest change in temperature of 3 C. Numerous experimental pitfalls are identified and discussed. Collectively, these data and the technique used to generate them should help future investigators make more accurate and precise measurements of the mechanical properties of freestanding thin films using nanoindentation.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1049203
- Journal Information:
- Journal of Materials Research, Vol. 24, Issue 9; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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