Exceptionally high-strength (@3 GPa) aluminum alloys demonstrated by oxygen ion implantation
Oxygen-implanted Al surface layers are shown to have exceptional flow stresses, with values up to 2.9 GPa for 20 at.% 0. Quantitative evaluations are obtained by probing the hardness with low-load indentation and evaluating the combined response of the layer and substrate with finite element modeling. The high densities of nanometer-size oxide precipitates observed with TEM account for the high strengths through conventional dispersion hardening theory. High strength is found even after the 20% alloy is annealed at 550{degrees}C (1.2 GPa). Relatively high strengths are also found for unannealed Al implanted with as little as 5 at.% 0 (1.4 GPa). In addition, the coefficient of friction of Al and associated stick-slip adhesion are greatly reduced by 0 implantation. This work indicates that the fcc Al matrix can be precipitation hardened far beyond the strengths of current aerospace alloys ({approximately}0.5 GPa), and that conventional hardening theories can be applied to high volume fractions of nanometer-size precipitates to aid in designing new high-strength alloys. Aluminum oxide precipitates should be considered for strengthening Al alloys because of their effectiveness in blocking dislocation motion at small sizes ({approximately}l mn) and their relatively high thermal stability. Oxygen implantation should be evaluated for treatment of Al-alloy engineering components in sliding contact to improve their tribological performance.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 7253564
- Report Number(s):
- SAND-92-0213C; CONF-921183--3; ON: DE92040980
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103 -- Metals & Alloys-- Mechanical Properties
360106* -- Metals & Alloys-- Radiation Effects
ALUMINIUM
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BEAMS
CHALCOGENIDES
CHARGED PARTICLES
DEPTH
DIMENSIONS
DISTRIBUTION
ELEMENTS
ENERGY RANGE
FLOW STRESS
FRICTION
HARDENING
ION BEAMS
ION IMPLANTATION
IONS
KEV RANGE
KEV RANGE 10-100
KEV RANGE 100-1000
LAYERS
METALS
OXIDES
OXYGEN COMPOUNDS
OXYGEN IONS
PRECIPITATION HARDENING
SPATIAL DISTRIBUTION
STRESSES
SURFACE TREATMENTS
TRIBOLOGY
WEAR