Microstructure analysis of melt-spun Al{sub 3}Ti intermetallics by XRD and EXAFS
- Rice Univ., Houston, TX (United States). Dept. of Mechanical Engineering and Materials Science
- Naval Air Warfare Center, Patuxent River, MD (United States). Aircraft Div.
In an effort to expand the composition range over which Al{sub 3}Ti is stable, various amounts of niobium were substituted for titanium and processed by melt-spinning. Several samples were annealed both at 600 C and 1,000 C for 24 hours. The effects of processing parameters such as wheel speed, the amount of niobium, and annealing temperatures on the structure were investigated by XRD and EXAFS. XRD showed that for all the samples the only structure present was DO{sub 22}. The DO{sub 22} structure was stable even after the high temperature heat treatments. By means of EXAFS, niobium atoms were observed to occupy titanium sites in the DO{sub 22} structure. Furthermore, in the unannealed samples, increasing wheel speed of the melt spinning process or the niobium concentration tended to distort the crystal structure. It was observed that Ti EXAFS had different results from the Nb EXAFS beyond their occupying similar sites, which suggested there may exist some composition zones, i.e., rich Nb zone or rich Ti zones, although the structures present were still DO{sub 22}. The samples were found to experience different distortions as a function of annealing temperatures.
- Sponsoring Organization:
- Advanced Research Projects Agency, Washington, DC (United States); Office of Naval Research, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
- OSTI ID:
- 571715
- Report Number(s):
- CONF-961202-; TRN: IM9806%%54
- Resource Relation:
- Conference: 1996 Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 2-6 Dec 1996; Other Information: PBD: 1997; Related Information: Is Part Of High-temperature ordered intermetallic alloys VII; Koch, C.C. [ed.] [North Carolina State Univ., Raleigh, NC (United States)]; Liu, C.T. [ed.] [Oak Ridge National Lab., TN (United States)]; Stoloff, N.S. [ed.] [Rensselaer Polytechnic Inst., Troy, NY (United States)]; Wanner, A. [ed.] [Univ. Stuttgart (Germany)]; PB: 799 p.; Materials Research Society symposium proceedings, Volume 460
- Country of Publication:
- United States
- Language:
- English
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