A structural analysis of Al(3)Ti and Al(3)Ti-Nb titanium trialuminides by XRD and EXAFS

Date
1997
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Abstract

In an effort to expand the composition range over which Al\sb3Ti is stable, various amounts of niobium were substituted for titanium and processed by melt-spinning. In order to characterize Al\sb3Ti\sbxNb\sby, where x + y = 1 and y = 0.0, 0.1, 0.2, and 0.4 intermetallics, XRD and EXAFS were employed. Several samples were annealed both at 600\sp∘C and 1000\sp∘C. XRD showed that for all the samples the only structure present was the tetragonal DO\sb22 structure. The DO\sb22 structure was stable even after high temperatures heat treatments. Niobium atoms were observed to occupy titanium sites in DO\sb22 by EXAFS. 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. The samples were found to experience an order-disorder-order process with change of the annealing temperatures.

Description
Degree
Master of Science
Type
Thesis
Keywords
Condensed matter physics, Engineering, Materials science
Citation

Chen, Jinmin. "A structural analysis of Al(3)Ti and Al(3)Ti-Nb titanium trialuminides by XRD and EXAFS." (1997) Master’s Thesis, Rice University. https://hdl.handle.net/1911/17070.

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