Abstract
We present the possibility of extracting the strain rate sensitivity, activation volume and Helmholtz free energy (for dislocation activation) using just one indentation stress relaxation test, and the approach is demonstrated with polycrystalline copper. The Helmholtz free energy measured from indentation relaxation agrees well with that from the conventional compression relaxation test, which validates the proposed approach. From the indentation relaxation test, the measured indentation strain rate sensitivity exponent is found to be slightly larger, and the indentation activation volume much smaller, than their counterparts from the compression test. The results indicate the involvement of multiple dislocation mechanisms in the indentation test.
| Original language | English |
|---|---|
| Article number | 245401 |
| Number of pages | 5 |
| Journal | Journal of Physics D: Applied Physics |
| Volume | 43 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - 23 Jun 2010 |
| Externally published | Yes |
Funding
This work is supported by the National Science Foundation CMMI-CAREER-0643726 and the Research Fund for the Doctoral Program of Higher Education of China N6CJ0001. XC is also supported by a Chang Jiang Scholar Program of the Ministry of Education of China, by a World Class University (WCU) program through the National Research Foundation of Korea (R32-2008-000-20042-0), and by the National Natural Science Foundation of China, Grant No 50928601.