Nickel Aluminides: A New Family of Nickel + Aluminum Alloys Featuring Simple Composition, Low Density, Excellent Oxidation Resistance, and High Yield Strength That Increases with Temperature

摘要

The three alloys presented in this brochure are based on the intermetallic compound Ni sub 3 Al. Ni sub 3 Al is brittle, but by changing the composition to Ni sub 76 Al sub 24 and adding /approximately/200 ppM boron the alloy becomes ductile. The strength of these alloys depends entirely on the behavior of the ordered crystal structure and the grain size. Larger grain size favors good high temperature strength and fine grain size favors good low temperature strength. An unusual feature of the strength is that in annealed material the yield stress increases with test temperature up to about 800/degree/C. Nickel aluminides display excellent oxidation and corrosion resistance characteristics which can be further enhanced with simple additives. Forming and processing can be accomplished by a variety of methods. Molten aluminides can be formed into ingots, castings, and near net shapes by several different processes. Nickel Aluminides can also be produced and consolidated from powder. Both cast and powder ingots, sheet, tube hollows, and rod can be further processed in several ways. (ERA citation 13:036791)