Pressure Induced Liquid-to-Liquid Transition in Zr-based Supercooled Melts and Pressure Quenched Glasses

Abstract

Through high-energy x-ray diffraction and atomic pair density function analysis we find that Zr-based metallic alloy, heated to the supercooled liquid state under hydrostatic pressure and then quenched to room temperature, exhibits a distinct glassy structure. The PDF indicates that the Zr-Zr distances in this glass are significantly reduced compared to those quenched without pressure. Annealing at the glass transition temperature at ambient pressure reverses structural changes and the initial glassy state is recovered. This result suggests that pressure causes a liquid-to-liquid phase transition in this metallic alloy supercooled melt. Such a pressure induced transition is known for covalent liquids, but has not been observed for metallic liquids. The High Pressure Quenched glasses are stable in ambient conditions after decompression.

Unveiling a new type of ultradense anomalous metallic glass with improved strength and ductility through a high-pressure heat treatment

“…In particular, polymorphic transition induced by pressure has been observed in many metallic glass systems [1][2][3][4][5] . The pressureinduced liquid-to-liquid transition was suggested by Dmowski et al in Zr-based metallic glasses 6 . In molecular dynamic (MD) simulation studies, polymorphic transitions and the creation of new types of abnormal glass through high-pressure heat treatment was predicted (i.e., a high-energy but high-density and well-ordered glass 7,8 ).…”

“…The high-pressure experiments were conducted on the rod samples using a belt-type large-volume press apparatus. In preparing the high-pressure heat-treated samples, we referred to a previous study by Dmowski et al to determine the experimental conditions 6 . An annealing temperature of 850 K, which might be slightly below T x , and an applied pressure of 5.5 GPa were selected.…”

“…Previously, Dmowski et al prepared a high-pressure heat-treated sample comprising a Zr-based metallic glass and discussed the glasses created at the high pressures and high temperatures 6 . However, they investigated only the atomic-scale structures of the created glasses by using the X-ray diffraction technique so that the material properties (e.g., thermal and mechanical properties) of the sample were not evaluated.…”

High-pressure annealing driven nanocrystal formation in Zr50Cu40Al10 metallic glass and strength increase

“…Dmowski et al 14 proposed that liquid-to-liquid transition occurs in Zr-based MGs, when they are heated to the supercooled liquid state under high-pressure conditions (~4-8 GPa). Notably, the high-pressure structure reported in Dmowski et al 14 is quenchable to room-pressure condition.…”

“…Dmowski et al 14 proposed that liquid-to-liquid transition occurs in Zr-based MGs, when they are heated to the supercooled liquid state under high-pressure conditions (~4-8 GPa). Notably, the high-pressure structure reported in Dmowski et al 14 is quenchable to room-pressure condition. The discovery of the quenchable high-pressure and high-temperature amorphous structure in Zr-based MGs is expected to open a new way to synthesize new MG materials, with unexpected structural and physical properties.…”