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Microstructure and tensile properties of Fe-40 at. pct Al alloys with C, Zr, Hf, and B additionsThe influence of small additions of C, Zr, and Hf, alone or in combination with B, on the microstructure and tensile behavior of substoichiometric FeAl was investigated. Tensile properties were determined from 300 to 1100 K on powder which was consolidated by hot extrusion. All materials possessed some ductility at room temperature, although ternary additions generally reduced ductility compared to the binary alloy. Adding B to the C- and Zr-containing alloys changed the fracture mode from intergranular to transgranular and restored the ductility to approximately 5 percent elongation. Additions of Zr and Hf increased strength up to about 900 K. Fe6Al6Zr and Fe6Al6Hf precipitates, both with identical body-centered tetragonal structures, were identified as the principal second phase in these alloys. Strength decreased steadily as temperature increased above 700 K, as diffusion-assisted mechanisms became operative. Although all alloys had similar strengths at 1100 K, Hf additions significantly improved high-temperature ductility by suppressing cavitation.
Document ID
19900024596
Document Type
Reprint (Version printed in journal)
Authors
Gaydosh, D. J. (NASA Lewis Research Center Cleveland, OH, United States)
Draper, S. L. (NASA Lewis Research Center Cleveland, OH, United States)
Nathal, M. V. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 14, 2013
Publication Date
September 1, 1989
Publication Information
Publication: Metallurgical Transactions A - Physical Metallurgy and Materials Science
Volume: 20A
ISSN: 0360-2133
Subject Category
METALLIC MATERIALS
Distribution Limits
Public
Copyright
Other