Development of Iron Aluminides.
Abstract
A program was conducted to develop improved iron-aluminide alloys with higher elevated temperature strength and room temperature ductility compared to the baseline Fe3Al alloy. The technical approach involved the screening evaluation of two experimental series of alloys which then formed the basis for the selection of a single alloy composition for more complete properties testing. The screening studies involved the evaluation of precipitation strengthening as well as solid solution strengthening alloy additions to the Fe3Al system. The most optimum of the precipitation strengthened alloys contained 2 a/o Nb and in the fully solution heat treated and aged condition exhibited 4 times the 600 C (1112 F) yield strength of Fe3Al, with about 60% the room temperature elongation. A negative feature of the two-phase alloys, however, was the occurrence of quench cracking, discovered during heat treatment of isothermally forged material. The most optimum of the solid solution strengthened alloys contained 3.5 Cr + 0.5 Mo (atomic percent) and exhibited 1.3 times the 600 C (1112 F) yield strength of Fe3Al, with equivalent room temperature ductility (4.8 percent elongation). Additional positive features of all the alloys were the attractive oxidation resistance compared to the Fe3Al baseline and the high degree of workability demonstrated during upset isothermal forging studies. Final alloy evaluation was conducted on Fe-35Al-4Cr-2Mo. Keywords: Powder metallurgy; Creep rupture; Fatigue resistance; Hot extrusion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1986
- Accession Number
- ADA168578
Entities
People
- C. S. Kortovich
- G. C. Culbertson