Metastable bcc phase formation in the Nb-Cr-Ti system
- Los Alamos National Lab., NM (United States)
- Wisconsin Univ., Madison, WI (United States). Dept. of Materials Science and Engineering
Metastable disordered bcc phases have been formed from the melt in the Nb-Cr-Ti system where primary Laves phases would develop under equilibrium solidification conditions. Three vertical temperature-composition sections in the ternary system incorporating NbCr, were evaluated: the Nb-Cr binary, the TiCr{sub 2}-NbCr{sub 2} isoplethal section, and the NbCr{sub 2}-Ti plethal section. In the rapid solidification of NbCr{sub 2}, metastable bcc phase formation was not observed, but deviations from NbCr{sub 2} stoichiometry or alloying with Ti was found to promote bcc phase formation by decreasing the required liquid undercooling to reach the metastable bcc liquidus and solidus. The metastable phases were characterized through x-ray diffraction (XRD), and systematic deviations from Vegard`s Rule have been defined in the three plethal sections. The metastable bcc phases decompose at temperatures >800{degrees}C to uniformly refined microstructures. As a result, novel microstructural tailoring schemes are possible through the metastable precursor microstructures.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- Department of Defense, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10171859
- Report Number(s):
- LA-UR--94-2528; CONF-9406229--1; ON: DE94016212; CNN: Grant ARO-DAAL-03090-G-0183
- Country of Publication:
- United States
- Language:
- English
Similar Records
Defects and site occupancies in Nb-Cr-Ti C15 Laves phase alloys
TITANIUM-NIOBIUM-CHROMIUM SOLIDUS SURFACE