About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
|
Bulk Metallic Glasses XVII
|
Presentation Title |
Nucleation of Shear Bands in Al-based Metallic Glasses and Their Composites |
Author(s) |
Wan Kim, Guen Hee Yoo, Eun Soo Park, John Perepezko |
On-Site Speaker (Planned) |
Wan Kim |
Abstract Scope |
A shear band(SB) is a region of highly localized plastic flow that develops during loading in metallic glasses(MGs). The deformation by SB is a nucleation-controlled process, however the initiation of the process is unclear. In the present study, we carefully investigate SB nucleation by measuring the first pop-in events via nanoindentation test. The statistical analysis of shear avalanches in Al90-xNi10MMx (x=2, 4, 6) MGs and Al88Ni10MM2 MG composites with different sizes and fractions of alpha-Al nanocrystals reveal the structural effects on the stochastic SB nucleation behavior. As a result, we discovered that there is the bimodal distribution of the first pop-in loads that are associated with different SB nucleation sites by concentrated shear mechanism and diffuse shear transformation mechanism. The density of each site, the nucleation barriers, and the nucleation kinetics have been carefully determined. These results offer novel guideline how to tailor the ductility of glass-forming alloys. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |