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Deformation and fracture of a directionally solidified NiAl-28Cr-6Mo eutectic alloyA directionally solidified alloy based on the NiAl-(Cr, Mo) eutectic was examined by transmission and scanning electron microscopy to characterize the microstructure and room temperature deformation and fracture behavior. The microstructure consisted of a lamellar morphology with a group of zone axes (111) growth direction for both the NiAl and (Cr, Mo) phases. The interphase boundary between the eutectic phases was semicoherent and composed of a well-defined dislocation network. In addition, a fine array of coherent NiAl precipitates was dispersed throughout the (Cr, Mo) phase. The eutectic morphology was stable at 1300 K with only coarsening of the NiAl precipitates occurring after heat treatment for 1.8 ks (500 h). Fracture of the aligned eutectic is characterized primarily by a crack bridging/renucleation mechanism and is controlled by the strength of the semicoherent interface between the two phases. However, contributions to the toughness of the eutectic may arise from plastic deformation of the NiAl phase and the geometry associated with the fracture surface.
Document ID
19960011341
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Chen, X. F.
(Tennessee Univ. Knoxville, TN, United States)
Johnson, D. R.
(Tennessee Univ. Knoxville, TN, United States)
Noebe, R. D.
(NASA Lewis Research Center Cleveland, OH., United States)
Oliver, B. F.
(Tennessee Univ. Knoxville, TN, United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1995
Subject Category
Metallic Materials
Report/Patent Number
NAS 1.26:200016
NASA-CR-200016
NIPS-96-07174
Accession Number
96N17777
Funding Number(s)
CONTRACT_GRANT: NAG3-876
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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