The ω phase in a Zr-25 at.% Ti alloy

Structural State of ?-Solid Solution in Quenched Quasicrystal-Forming Alloys of Al61Cu26Fe13

“…An ªidealº hexagonal w-phase is formed at a certain critical concentration of the b.c.c.-alloy. It is known [21,22] that this phase is realized due to the instability of the b.c.c. lattice to the longitudinal wave of atomic displacements (2/3)K 111 (or to the transverse-polarized wave (1/3)K 112 ).…”

Omega-phase in Ti-Hf-Zr alloys produced by the hydride-cycle methodSpecial issue on Neutron Scattering in Canada.

“…Zr, Ti, and Hf are all very effective O getters. Sass reported an experiment on an alloy formed from zone-refined Zr and Ti quenched in diffusion pump oil from 1000 8C: when the heat treatment was done in Ar, u-phase was retained, whereas the same heat treatment done in a 5 Â 10 -5 torr (1 torr = 133.322 4 Pa) vacuum prior to quenching resulted in no u-formation [47]. In bottled Ar, trace amounts of N 2 and O 2 remain, and it seems probable that it is the effect of these small amounts of impurities that caused retention of u [14,40,47].…”

“…Sass reported an experiment on an alloy formed from zone-refined Zr and Ti quenched in diffusion pump oil from 1000 8C: when the heat treatment was done in Ar, u-phase was retained, whereas the same heat treatment done in a 5 Â 10 -5 torr (1 torr = 133.322 4 Pa) vacuum prior to quenching resulted in no u-formation [47]. In bottled Ar, trace amounts of N 2 and O 2 remain, and it seems probable that it is the effect of these small amounts of impurities that caused retention of u [14,40,47]. Therefore, it is likely that there is a continuum of structures, from the u-alloy containing a few octahedral interstitials to Ti 2 ZrO, so that the structure could be described as a defect, or interstitial, solid solution of O and octahedral vacancies: Ti 2-x (Zr,Hf) x O y & 1-y , where y could take a wide variety of values from near zero to 1.…”

“…There is an error in the ICSD database concerning the orthorhombic, fully O-ordered u-phase. It is probable that the u-phase exists all the way from a stoichiometric oxide such as Ti 2 ZrO to nearly pure alloy, stabilized by very small amounts of in- terstitials [47]. Therefore, the appearance of any u phase at ambient (T,P) in the X-ray powder diffraction of Ti-Zr-Hf alloys may be a sign of contamination, probably by O, as X-ray powder diffraction of alloys containing even 10 atom% O can barely distinguish alloy from oxide.…”

Decomposition Processes of β Phase in a Ti-15Zr-4Nb-4Ta Alloy

“…Such ! precipitation [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] has also been observed in Ti based alloys. Since the holding temperature, 600…”