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Deformation behavior of NiAl-based alloys containing iron, cobalt, and hafniumThe effects of alloying additions on the mechanical properties of the B2 intermetallic NiAl have been investigated in both the melt-spun ribbon and consolidated, bulk form. The study is based on a matrix of NiAl-based alloys with up to 20 at. pct Co and Fe additions and with reduced Al levels in the range of 30-40 at. pct. Characterization of the melt-spun ribbon by optical and scanning electron microscopy indicates a range of microstructures, including single-phase beta, gamma-prime necklace phase surrounding either martensitic or beta grains, and a mixture of equiaxed martensitic and gamma-prime grains. Bend ductility is present in melt-spun and annealed ribbons exhibiting the gamma-prime necklace structure and in a single-phase beta material containing 20 at. pct Fe. The analysis of compressive flow behavior on consolidated, bulk specimens indicates that the single-phase beta alloys exhibit a continuous decrease in yield stress with increasing temperature and profuse microcracking at grain boundaries. In contrast, multiphase (gamma-prime + either martensite or beta) alloys tend to display a peak in flow stress between 600 and 800 K, with little or no signs of microcracking. In general, heat treatments which convert the martensitic grains to beta + gamma-prime result in improved strength at temperatures above 600 K and better resistance to crack initiation.
Document ID
19900029875
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Pank, D. R.
(Pennsylvania State Univ. University Park, PA, United States)
Koss, D. A.
(Pennsylvania State University University Park, United States)
Nathal, M. V.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1989
Subject Category
Metallic Materials
Meeting Information
Meeting: Symposium on High-Temperature Ordered Intermetallic Alloys III
Location: Boston, MA
Country: United States
Start Date: November 29, 1988
End Date: December 1, 1988
Sponsors: U.S. Navy, DOE, General Electric Co., NASA
Accession Number
90A16930
Distribution Limits
Public
Copyright
Other

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