Nonequilibrium alloying of graphite-reinforced aluminum metal matrix composites

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Corrosion (Houston); (United States)

DOI:https://doi.org/10.5006/1.3316008· OSTI ID:5625546

Schrecengost, T R ^[1]; Shaw, B A ^[2]; Wendt, R G; Moshier, W C ^[3]

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1. Elliott Co., Jeannette, PA (United States)
2. Pennsylvania State Univ., University Park, PA (United States)
3. Martin Marietta Astronautics Group, Denver, CO (United States)

With corrosion behavior superior to pure aluminum (Al), nonequilibrium Al alloys produced by cosputter deposition have great potential for use a s matrix metals in graphite (Gr)-reinforced Al composites. These composites offer enhanced properties as a result of their low density matrix and a high modulus reinforcing fiber. Cosputter-deposited Al alloys provide a means to improve corrosion resistance of Al and to remove a conventional processing step that accelerates degradation of the composite once the Gr fibers are exposed. Additions of tungsten (W) and molybdenum (Mo) were found to enhance the localized corrosion resistance of Al. At concentrations of 19 at.% Mo or 26 at.% W breakdown potentials (E[sub b]) increased by 1,115 mV[sub sce] and 1,245 mV[sub sce] over pure Al, respectively. Heat treatment of these alloys at 400 C. for 1 h did not result in precipitation of a second phase. The alloys maintained excellent resistance to localized attack. Galvanic current diagrams predicted use of these alloys in composite structures would decrease galvanic corrosion rates by at least 2 orders of magnitude. This enhancement in galvanic corrosion resistance was a result of significant improvements in passivity which occurred with the nonequilibrium addition of Mo or W to Al. Galvanic current measurements confirmed the predicted reduction in galvanic corrosion rates.

• OSTI ID: 5625546
• Journal Information: Corrosion (Houston); (United States), Journal Name: Corrosion (Houston); (United States) Vol. 49:10; ISSN 0010-9312; ISSN CORRAK
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360604* -- Materials-- Corrosion
Erosion
& Degradation
ALLOYS
ALUMINIUM ALLOYS
CARBON
CHEMICAL REACTIONS
COMPOSITE MATERIALS
CORROSION
CORROSION RESISTANCE
ELEMENTAL MINERALS
ELEMENTS
GRAPHITE
MATERIALS
MATRIX MATERIALS
MINERALS
MOLYBDENUM ADDITIONS
MOLYBDENUM ALLOYS
NONMETALS
TUNGSTEN ADDITIONS
TUNGSTEN ALLOYS