Microstructure investigation in B2-phased Ni-25Al-40Fe intermetallic compound
- National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Materials Science and Engineering
To change the microstructures and improve the room-temperature ductility of B2-structured ({beta}{prime} phase) NiAl intermetallic compound, macroalloying with iron was reported by referring previous literature. In the previous investigation on the Ni-25Al-xFe alloys (x is from 20 to 40 at.%), the alloy was prepared by bulk-processing because of convenience for structural application. Therefore, the significant segregation could not be avoided due to the cooling rate. In the Ni-25Al-xFe alloy system, the alloys exhibited two-phased dendritic microstructures when x was lower than 40 at.%. The as-cast morphologies changed to a single-phased granular structure after the Fe-content reached to 40 at.%. This single phase existing in the as-cast Ni-25Al-40Fe alloy was identified as an ordered bcc {beta}{prime} phase like {beta}{prime}-NiAl by TEM and XRD analysis. The B2-phased compounds show a typical CsCl structure which is 3/2 Hume-Rothery electron compound (1.5 electrons/atom), order at high temperatures and has many interesting properties, as described by some literature. This B2 phase also revealed unusual diffraction patterns and images when examined in the transmission electron microscope. In this paper, the authors will show the behavior similarity of this bulk-processed Ni-25Al-40Fe alloy, moreover report the effect of segregation and the precipitates in the alloy during annealing.
- OSTI ID:
- 186808
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 2 Vol. 34; ISSN 1359-6462; ISSN XZ503X
- Country of Publication:
- United States
- Language:
- English
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