Abstract
We observed very high thermal stability (after annealing at 600 °C for 1 h) of the near-surface layers of ultrafine grains in the 99.9995 wt% (5N5) purity Cu processed by high-pressure torsion. We attributed this extraordinary thermal stability of ultrafine-grained microstructure to the nitrogen-filled nano-sized pores that pinned the grain boundaries. Our study reveals that a combination of severe shear strain and surface attrition causes the capture of N2 molecules in the near-surface layer of the deformed metal from the ambient atmosphere. This phenomenon may play an important role in formation of percolating porosity in metals processed by severe plastic deformation.
Original language | English |
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Pages (from-to) | 29-33 |
Number of pages | 5 |
Journal | Scripta Materialia |
Volume | 178 |
DOIs | |
State | Published - 15 Mar 2020 |
Keywords
- Copper
- Electron energy loss spectroscopy (EELS)
- Grain boundary migration
- High-pressure torsion
- Thermal stability
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- General Materials Science