About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
30 Years of Nanoindentation with the Oliver-Pharr Method and Beyond
|
Presentation Title |
Comparison between Long-term Nanoindentation Creep Testing under Constant Load and Constant Pressure |
Author(s) |
Thomas Chudoba |
On-Site Speaker (Planned) |
Thomas Chudoba |
Abstract Scope |
Creep effects can be observed during nanoindentation experiments when the load is held constant at maximum force. Attempts to correlate nanoindentation creep curves under constant load with the results of macroscopic creep tests failed because the depth change under load is accompanied by a pressure reduction, while uniaxial creep tests are done under constant stress. Further, the thermal drift is reducing the accuracy for measurements with nanometer resolution.
A test methodology has been developed that allows measurements under constant pressure and that considers thermal drift effects. The necessary calculations are done live during the measurement and used to correct force and depth accordingly. Pressure calculation and drift correction are based on dynamic contact stiffness measurements and on the assumption of a constant modulus. Results are presented for several materials and pressure levels and compared with creep results from constant force experiments. |
Proceedings Inclusion? |
Planned: |
Keywords |
Mechanical Properties, Characterization, Surface Modification and Coatings |