Determination of Al Site Preference in L1₂ TiZn₃ - Base Trialuminides

Abstract

The atoms site preference in the Al3Ti-Zn system has been studied using H. Rietveld method. The L12 Ti(Al, Zn)3 particles evolve in a ZnAl25 melt from the L12TiZn3 particles in the ZnTi4 master alloy. It is found that Zn is replaced by Al during the transformation TiZn3 → Ti(Al, Zn)3. In the evolving fcc L12 Ti(Al, Zn)3 phase Ti occupies (0, 0, 0) position while Al and Zn occupy (0, 0.5, 0.5) position, similarly to Al and X in the Al3Ti-X systems, where X = Ni, Cr, Mn, Cu, Ag, Pd [1, 2].

The crystal structure, microhardness and thermal stability of the Ti26Al55Zn19 alloy

“…Raman and Schubert [15] synthesized Ti 25 Al 66 Zn 9 alloy by sintering pure Al, Zn and Ti powders and obtained a mixture of D0 22 and L1 2 phases. Krajewski [16] studied the atom site preference in TiZn 3 -base trialuminides using H. Rietveld method and observed that Zn was replaced by Al during the transformation from TiZn 3 to Ti(Al,Zn) 3 . Delsante et al [17] measured the formation heat of alloys along the TiZn 3 eTiAl 3 section at 27 C using a high temperature direct drop calorimeter and detected two phases in Ti 25 Al 65 Zn 10 sample, but only one phase with structure similar to that of TiZn 3 was observed in Ti 25 Al x Zn 75Àx (x ¼ 10, 20, 28 and 40) sample.…”

Crystallographic study of grain refinement of Al by Nb addition

“…The predictions quantitatively fit the measured grain size in standard (TP-1) tests on commercial purity and other aluminium alloys inoculated with an Al-Ti-B refiner. In addition, Krajewski and Greer (Krajewski, 2006;Krajewski & Greer, 2006) studied the microstructure of cast Zn-25 wt% Al alloy grain refined by a Zn-4 wt% Ti master alloy. They found that many in situ formed L1 2 Ti(Al, Zn) 3 particles with a size of around a few micrometres were located within the refined 0 -Zn-Al grains, which agrees well with the free growth model.…”

Experimental investigation and thermodynamic optimization of the Al–Zn–Ti system in the Al-rich corner

“…For the ternary phase, Raman and Schubert [30] synthesized Al 66 Zn 9 Ti 25 alloy by sintering pure Al, Ti and Zn powders and obtained a mixture of D0 22 and L1 2 phases. Krajewski [31] studied the atom site preference in TiZn 3 -based trialuminides using H. Rietveld method, and found that Zn was replaced by Al during the transformation from TiZn 3 to Ti(Al,Zn) 3 . In our previous work [16], the existence of the seTi 26 Al 55 Zn 19 phase has been confirmed by Zn/TiAl 3 diffusion couple at 400 C. The crystal structure and thermal stability of the seTi 26 Al 55 Zn 19 alloy were experimentally determined.…”