Identification of a new tetragonal phase in the Nb-Ti-Al system |
| |
| Authors: | Keith J. Leonard Joseph C. Mishurda Bryan Molloseau Marc De Graef Vijay K. Vasudevan |
| |
| Affiliation: | 1. Institut für Theoretische Physik C, Technische Hochschule Aachen , D-5100, Aachen, Germany;2. Moscow Engineering Physics Institute , Moscow, U.S.S.R;3. Laboratoire des propriétes méchaniques et thermodynamique des matériaux , C.N.R.S. Université Paris-Nord, Avenue J. B. Clément , F-93430, Villetaneuse, France |
| |
| Abstract: | During the course of investigation of the phase equilibria in the Nb-Ti-Al system, a new phase, designated theta, was observed in three Nb-Ti-40at.%Al alloys following ageing at low temperatures (less than 1000 C). Using X-ray diffraction and transmission electron microscopy techniques, this phase was determined to have a bct structure, with lattice parameters a0 = 5.106 A and c0 = 28.168A, a space group of I 41/amd (number 141) and composition near 45at.%Nb25at.%Ti-30at.%Al. An orientation relationship between the new tetragonal phase and the gamma-TiAl phase of [101]gamma//[120]theta and (111)gamma//(001)theta was observed within the microstructure. |
| |
| Keywords: | |
|
|
