Local structure and site substitution in amorphous and quasicrystalline Zr–Ti–Ni–(Cu) alloys

Abstract

Local structures of amorphous and quasicrystalline phases in Zr–Ti–Ni and Zr–Ti–Ni–Cu alloys have been studied by means of x-ray absorption spectroscopy. The amorphous phases show a high degree of icosahedral short-range order. In all investigated systems local order around Cu and Ni atoms was found to be nearly identical pointing to site substitution of Ni by Cu as the reason for an improved glass forming ability when Ni is partly substituted by Cu. The results strengthen an icosahedral cluster based approach for the structure of metallic glasses and indicate the importance of the medium-range order on glass formation.

Atomic structure of nanoscale quasicrystal-forming Zr–noble metal binary metallic glasses

“…It is due to the stable clusters originating from the strong chemical affinity between Zr and noble metal. The investigation described above has been strongly suggested in the recent studies [10,21,22]. Mechler et al [21] have reported that QC grows from the undercooled liquid more likely by the attachment of performed icosahedral clusters, rather than by a single atom attachment in the local structure studies in Zr-Ti-Ni-Cu metallic glass.…”

“…The investigation described above has been strongly suggested in the recent studies [10,21,22]. Mechler et al [21] have reported that QC grows from the undercooled liquid more likely by the attachment of performed icosahedral clusters, rather than by a single atom attachment in the local structure studies in Zr-Ti-Ni-Cu metallic glass. The simulation study has also pointed out that icosahedral clusters would like to "wet" the core of the QC nucleus owing to the reduction of interfacial tension.…”

Review of the highlights of X-ray studies of liquid metal surfaces

“…4 for the Au 82 Si 18 eutectic alloy 19 and which was found again for the Ag-CuSi-Ag-Pd glass forming alloy. 31 In view of the fact that this type of surface freezing is not observed for Au 72 Ge 28 , which has a similar eutectic phase and similar chemistry to Au 82 Su 18 but which does not form a metallic glass in the same way as Au 82 Si 18 , it is tempting to conclude that surface freezing is associated with the glass forming ability. This is one subject that needs further exploration.…”

“…In addition, it appears as though they all have well developed short-range order that is often in the form of icosahedral packing. [26][27][28][29] One suggestion is that the icosahedral packing inhibits formation of the bulk crystalline phase on cooling. 30 Mechler et al suggested that surface freezing and glass formation might have a common origin.…”

Crystalline monolayer surface of liquid Au–Cu–Si–Ag–Pd: Metallic glass former

“…This SRO often appears in the form of an icosahedral SRO and/or medium range order in the liquid and the resulting amorphous phase. 13,14,16,17 It was suggested that this icosahedral order inhibits formation of bulk crystalline phases during undercooling/quenching. 18 In addition, the binary Au-Ge alloy cannot be quenched into an amorphous phase, 19 although it otherwise has similar properties than Au-Si.…”