16 Percent Aluminum-Iron Alloy Cold Rolled in the Order-Disorder Temperature Range

Abstract

The methods of fabricating 16 percent Al-Fe from cast slab to thin-gauge sheet are described in some detail. The melting, casting, homogenizing, hot rolling, and cold rolling at 575°C and room temperature are described. Particular attention is focused upon the 575°C cold rolling from the standpoint of the possible beneficial effects derived from an ordering reaction which occurs in this alloy. The technique of cold reduction from 0.007 in. to 0.0005 in. at room temperature is discussed. Magnetic data on a limited number of heat-treated laminated cores are given. Useful physical properties, other than magnetic, of previous limited interest because of the inability to fabricate the alloy into ductile strong thin sheets, are discussed. These properties include excellent oxidation resistance at high temperatures, good wet-corrosion resistance to certain chemical solutions, and high electrical resistivity.

Iron Aluminides

“…Developments of Fe-Al-based alloys in the United States can be traced back to at least the early 1950s, when alloy series termed Alfenol and Thermenol were developed at the Naval Ordnance Laboratory (13)(14)(15)(16), Ferral at the Ford Motor Company (17)(18)(19), DB-2 at The Martin Company (20,21), and Fe-Cr-Al at the Batelle Memorial Institute (22). Prototype duct halves and jet engine compressor blades were forged from these alloys, and furnace hearths, heat-treat boxes, and turbine exhaust cones were welded (13,15,16,23,24).…”

“…Whether the improved ductility of this alloy is due to internal stresses is not clear, as local X-ray diffraction investigations yielded no clear evidence. It has been frequently demonstrated that deformation processing can also improve ductility (14,34,(127)(128)(129)(130), although it is not clear whether, e.g., grain refinement or an increased number of mobile dislocations is responsible (123). Figure 7 includes examples of the improvement in ductility after rolling, forging, or additive manufacturing.…”

“…The possibility of producing plates, sheets, and tapes by hot and cold rolling of iron aluminides has been frequently demonstrated (14,(253)(254)(255). Alloys with an Al content of up to approximately 30-at% Al may be processed according to the parameters used for rolling of Cr steels (129,256).…”

“…However, ductility may be limited for coiling of sheets (260). From the produced sheets, laminated cores for magnetic applications and heating elements have been punched out (14,254).…”

Development and modeling of iron-gallium alloys

“…Process approaches that appear promising include growth texturing in an as-cast structure and the preferential recrystallization of thin sheets. Deformation texturing methods of interest, based on success in texturing of Fe-Si and Fe-Al alloys, include extrusion, forging and rolling [Nachman 1954, Kad 1997, Novikov 1997. A final potential texturing process includes the use of an aligning magnetic field in conjunction with powder metallurgy.…”