Formations of amorphous and quasicrystal phases in Ti–Zr–Ni–Cu alloys

Unusual devitrification behaviour in rapidly solidified Ti45Zr38Ni17 alloy

“…From previous research, it has been shown that quasicrystals precipitation is favoured dur- ing rapid solidification since the icosahedral short-range order (i-SRO), prevailing in the hot liquid, acts as QC nucleation sites [30][31][32][33]. Indeed, it is somewhere quite unexpected because it underlines the surprising low nucleation barrier of ␤ phase during rapid solidification process.…”

“…In fact, most reports assume that icosahedral short-range order (SRO), existing in the starting hot liquid, can locally remain in the amorphous phase after quench [30] and acts as basic atomic clusters in icosahedral QCs formation [31]. It is supported as well by the low energy barrier existing between QCs nuclei and liquid glass [32].…”

Effect of microalloying on the formation and stability of the Ti–Zr–Ni icosahedral quasicrystal

“…Among all the elements in group IB (Cu, Ag, and Au), only the sample with the addition of 2 at.% Ag was pure i-phase, based on the diffraction pattern. The addition of Cu significantly destabilizes the formation of the i-phase; Cu has been reported to help glass formation in Ti 45 Zr 35 Ni 20Àx Cu x alloys [18]. The addition of Pb slightly degrades the formation of the i-phase, as seen by the additional diffraction lines arising from the C14 Laves phase.…”

“…Instead of the more widely studied Zr-based alloys [4][5][6]14], we have chosen a Ti-Zr-Ni alloy, since earlier studies have shown [8,15,16] that stable quasicrystals can be formed directly from the liquid at moderate cooling rates (<100 K/s) over a fairly wide composition range for Ti and Zr, but for a very narrow composition range for Ni (20.5-21.5 at.%). Several elements (Cu, Ag, Au, Pt, Pb, and Si) were chosen for microalloying in a Ti 37 Zr 42 Ni 21 alloy, since earlier studies have shown that glass formability in Ti-Zr-Ni alloys improved by the addition of Ag [17], Cu [18], Si [19] and Pb [20]. No corresponding studies for the i-phase formation have been reported with microalloying in Ti-Zr-Ni alloys, however.…”

The impact of ambient gas on the magnetic properties of Ti40Zr40Ni20 powders during mechanical alloying

“…Besides melt-spinning [4,5] and suction-casting [6,7], rapid quenching methods and mechanical alloying with subsequent annealing [8,9] are the most commonly used methods for the preparation of Ti-Zr-Ni quasicrystals, which due to their high density of tetrahedral sites are candidates for hydrogen storage in future hydrogen-technology applications, i.e., PEM fuel cells and Ni-MH batteries. However, as previously reported by our group [10], amorphous and crystalline Ti-Zr-Ni samples also store hydrogen, although to a different extent.…”