Two-way tuning of structural order in metallic glasses

Abstract

Metallic glasses are expected to have quite tunable structures in their configuration space, without the strict constraints of a well-defined crystalline symmetry and large energy barriers separating different states in crystals. However, effectively modulating the structure of metallic glasses is rather difficult. Here, using complementary in situ synchrotron x-ray techniques, we reveal thermal-driven structural ordering in a Ce 65 Al 10 Co 25 metallic glass, and a reverse disordering process via a pressure-induced rejuvenation between two states with distinct structural order characteristics. Studies on other metallic glass samples with different compositions also show similar phenomena. Our findings demonstrate the feasibility of twoway structural tuning states in terms of their dramatic ordering and disordering far beyond the nearest-neighbor shells with the combination of temperature and pressure, extending accessible states of metallic glasses to unexplored configuration spaces.

Impact of Severe Deformation by HPT at Room Temperature on the Relaxation of the Glassy and the Supercooled Liquid States of PdNiP

“…Moreover, region A in Fig. 5 may also resemble a first-order transition of two amorphous phases (polyamorphism) 66,70,72 , represented in our case by the two different MRO networks. However, our data does not reveal a reentrant enthalpy change towards an ultra-stable second supercooled liquid configuration as reported for off-stoichiometric Pd 41.25 Ni 41.25 P 17.5 61 .…”

“…Kumar et al 71 performed TEM experiments on amorphous Zr 36 Ti 24 Be 40 suggesting that the occurrence of the exothermic peak is a consequence of shortrange order rearrangements paving the way for crystallization. Novel findings by Lou et al 72 using in-situ synchrotron Xray techniques also report an exothermic peak in the supercooled liquid. However, the observation of the exothermic peak was related to MRO changes involving ordering towards pre-nucleation sites 72 .…”

“…Novel findings by Lou et al 72 using in-situ synchrotron Xray techniques also report an exothermic peak in the supercooled liquid. However, the observation of the exothermic peak was related to MRO changes involving ordering towards pre-nucleation sites 72 . Moreover, additional transformations in the supercooled liquid region of Pd 41.25 Ni 41.25 P 17.5 were observed by Lan et al 73 using in-situ X-ray diffraction.…”

Nanostructured Metallic Glass in a Highly Upgraded Energy State Contributing to Efficient Catalytic Performance

“…One option to obtain the higher-energy MGs is faster and faster quenching from the molten state to the undercooled liquid to capture the higher energy state in liquid. [26] Various post-treatment processes to rejuvenate the MGs to higher energy state, such as cryogenic thermal cycling [27,28] or high-pressure treatment, [29,30] provide additional options, which have been explored extensively. These options face several problems due to the complex processing and, associated with that, large energy consumption.…”

Metallic Glacial Glass Formation by a First-Order Liquid–Liquid Transition

“…Liquid–liquid transition (LLT) is a first-order phase transition from one liquid to another liquid without the compositional change. LLTs have been reported in many glassy systems like amorphous ice, amorphous silicon, oxide glass, molecular glass, , and metallic glass (MG) systems. − To date, the presence of LLT in the metallic liquids at temperatures above the melting temperature ( T m ), including the manifestations of abrupt changes of liquid viscosity, the peak position of the diffraction peaks, and the Knight shift in nuclear magnetic resonance, have been reported in many MG systems. − Meanwhile, signs of LLT in the MG-forming supercooled liquid (SCL), − including a first-order exothermic transition at temperatures below T m and above the glass transition temperature ( T g ), have been reported. In these cases of the so-called reentrant glass transition, the MG first enters into its SCL via glass transition upon heating; then the SCL transforms to another amorphous phase through LLT; if quenched, new glass of higher T g is supposed to be made as it has an apparently glassy structure.…”