National Aeronautics and Space Administration (NASA)
Published: 2018-07-17
Total Pages: 144
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The feasibility of applying conventional hot forming and welding methods to high temperature aluminum alloy, Al-8Fe-1V-2Si (FVS812), for structural applications and the effect of thermal exposure on mechanical properties were determined. FVS812 (AA8009) sheet exhibited good hot forming and resistance welding characteristics. It was brake formed to 90 deg bends (0.5T bend radius) at temperatures greater than or equal to 390 C (730 F), indicating the feasibility of fabricating basic shapes, such as angles and zees. Hot forming of simple contoured-flanged parts was demonstrated. Resistance spot welds with good static and fatigue strength at room and elevated temperatures were readily produced. Extended vacuum degassing during billet fabrication reduced porosity in fusion and resistance welds. However, electron beam welding was not possible because of extreme degassing during welding, and gas-tungsten-arc welds were not acceptable because of severely degraded mechanical properties. The FVS812 alloy exhibited excellent high temperature strength stability after thermal exposures up to 315 C (600 F) for 1000 h. Extended billet degassing appeared to generally improve tensile ductility, fatigue strength, and notch toughness. But the effects of billet degassing and thermal exposure on properties need to be further clarified. The manufacture of zee-stiffened, riveted, and resistance-spot-welded compression panels was demonstrated. Kennedy, J. R. and Gilman, P. S. and Zedalis, M. S. and Skinner, D. J. and Peltier, J. M. Unspecified Center ALUMINUM ALLOYS; DIFFUSION WELDING; DISPERSION STRENGTHENING; FUSION WELDING; HIGH TEMPERATURE ENVIRONMENTS; MICROSTRUCTURE; SPOT WELDS; DEGASSING; DUCTILITY; ELECTRON BEAM WELDING; GAS TUNGSTEN ARC WELDING; HOT WORKING; NOTCH SENSITIVITY; SUPERPLASTICITY; TEMPERATURE EFFECTS; TENSILE STRENGTH; THERMAL FATIGUE...