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The pressure-induced transitions discovered in metallic glasses (MGs) have attracted considerable research interest offering an exciting opportunity to study polyamorphism in densely packed systems. Despite the large body of work on these systems, the elastic properties of the MGs during polyamorphic transitions remain unclear. Here, using an in situ high-pressure ultrasonic sound velocity technique integrated with x-ray radiography and x-ray diffraction in a Paris-Edinburgh cell, we accurately determined both the compressional and shear wave velocities of a polyamorphous Ce68Al10Cu20Co2 MG up to 5.8 GPa. We observed elastic anomalies of a MG with minima (at ∼1.5 GPa) in the sound velocities, bulk modulus, and Poisson's ratio during its polyamorphic transition. This behavior was discussed in comparison to the elastic anomalies of silica glass and crystalline Ce.

Long-range topological order (LRTO) was recently revealed in a Ce75Al25 metallic glass (MG) by a pressure-induced devitrification (PID) at 300 K. However, what compositions may have PID and an understanding of the physical and chemical controls behind PID are still not clear. We performed in situ high pressure x-ray diffraction measurements on CexAl1−x (x = 65, 70, and 80 at. %) MGs. Combining our experimental results and simulations, we found PID is very sensitive to compositions and can only exist over narrow compositional ranges. These results provide valuable guidance for searching for PID in MGs.

To be structural materials, the critical size is always a bottleneck of bulk metallic glasses (BMGs) due to the cooling rate restriction. Here, we report a developed alloy of Zr46Cu30.14Ag8.36Al8Be7.5, which can be cast into amorphous rods in 73 mm diameter by copper mould casting. The strong glass forming ability of this alloy is closely related to the Be addition, which not only suppresses the phase separation happening in the as-cast Be-free BMG but also sustains low Gibbs free energy difference for crystallization. This finding will stimulate more interests in developing BMGs and their industrial applications.

Atomic configurations of an Mg61Cu28Gd11 bulk metallic glass and its molten state have been investigated. The supercooled liquid and melt have a volume expansion coefficient only two times as large as that below glass transition temperature. Although the dominant polyhedra are 12- and 13-coordinated, the melt has slightly more polyhedra of low coordinated and less of high coordinated than in the as-cast. By Gd addition, half-octahedra with more volume accommodated are likely formed in the polyhedra, causing the local atomic environments of Mg in the melt quite different from the competing crystalline phase, thereby suppressing crystallization upon quenching.

The uniaxial tensile behavior of Zr62Al8Ni13Cu17, Cu46Zr46Al8, Zr48Cu43Al7Ag2, and La62Al14(Cu5/6Ag1/6)14Co5Ni5 bulk metallic glasses (BMGs) has been investigated by using in situ synchrotron radiation diffraction technique. It is found that the local strain is basically homogeneously distributed at low stress. However, heterogeneity appears obviously when the stress is close to the fracture strength. The amplitude of fluctuation in local strain for four BMGs could relate to the distribution of excess free volume within the medium range order.