Thesis
The effects of solid solution impurities corresponding to stacking fault energy on nanoindentation behavior in crystalline solids
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/102941
Abstract
The effects of solid solution impurities on small scale plasticity using nanoindentation was studied in a model face-centered-cubic alloy of copper and zinc. A copper-brass diffusion couple was formed using a long annealing time, and a typical (101) grain was identified for further study. Two sets of indentations were made within the single (101) grain for different zinc concentration. The expected solid-solution strengthening , where hardness increases with increasing zinc concentration, was documented as expected. However, the onset of plasticity, not only the deformation once existing dislocations exist, was also impacted by Zn concentration. The rapid initiation of plasticity at a given applied stress, the "pop-in", happens at higher loads as the zinc concentration is lowered. This change in concentration is associated with a higher stacking fault energy(SFE). The shear stress required to nucleate dislocation in 5%wt Zn-95%wtCu is approximately 1GPa while in 15%wt Zn-85%wt Cu a 0.8GPa shear stress is required. The results indicate impurities and therefore SFE has an effect on dislocation nucleation.
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Details
- Title
- The effects of solid solution impurities corresponding to stacking fault energy on nanoindentation behavior in crystalline solids
- Creators
- Bo Li
- Contributors
- David F. Bahr (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525047801842
- Language
- English
- Resource Type
- Thesis