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- Title
Deformation behavior and mechanisms of a nanocrystalline multi-phase aluminum alloy.
- Authors
Shaw, Leon L.; Luo, Hong
- Abstract
A nanocrystalline (nc) Al–Fe–Cr–Ti alloy containing 30 vol.% nc intermetallic particles has been used to investigate deformation behavior and mechanisms of nc multi-phase alloys. High compressive strengths at room and elevated temperatures have been demonstrated. However, tensile fracture strengths below 300 °C are lower than the corresponding maximum strengths in compression. Creep flow of the nc fcc-Al grains is suppressed even though rapid dynamic recovery has occurred. It is argued that the compressive strength at ambient temperature is controlled by propagation of dislocations into nc fcc-Al grains, whereas the compressive strength at elevated temperature is determined by dislocation propagation as well as dynamic recovery. The low tensile fracture strengths and lack of ductility at temperatures below 300 °C are attributed to the limited dislocation storage capacity of nanoscale grains. Since the deformation of the nc Al-alloy is controlled by dislocation propagation into nc fcc-Al grains, the smaller the grain size, the higher the strength. This new microstructural design methodology coupled with ductility-improving approaches could present opportunities for exploiting nc materials in structural applications at both ambient and elevated temperatures.
- Subjects
DEFORMATIONS (Mechanics); NANOCRYSTALS; ALUMINUM alloys; INTERMETALLIC compounds; METAL fractures; FRACTURE mechanics; DISLOCATIONS in crystals; STRENGTH of materials
- Publication
Journal of Materials Science, 2007, Vol 42, Issue 5, p1415
- ISSN
0022-2461
- Publication type
Article
- DOI
10.1007/s10853-006-1118-0