Exceptionally high-strength ({approximately}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:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 10180165
- Report Number(s):
- SAND-92-0213C; CONF-921183-3; ON: DE92040980
- Resource Relation:
- Conference: 8. international conference on TMS beam processing of advanced materials,Chicago, IL (United States),5 Nov 1992; Other Information: PBD: [1992]
- Country of Publication:
- United States
- Language:
- English
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