Does Bulk Metallic Glass of Elemental Zr and Ti Exist?

Abstract

To verify the high-pressure formation of the bulk metallic glass in elemental Zr and Ti, which Zhang and Zhao [Nature (London) 430, 332 (2004)] and Y. Wang et al. [Phys. Rev. Lett. 95, 155501 (2005)] recently reported, the high-pressure states were investigated by our newly developed in situ angle-dispersive x-ray diffraction using a two-dimensional detector and x-ray transparent anvils. Despite the disappearance of all the Bragg peaks in the one-dimensional energy-dispersive data, two-dimensional angle-dispersive data showed several intense Bragg spots even at the conditions where the amorphization was reported. This finding suggests that Zr and Ti do not transform into an amorphous state, but that their grain size becomes large, which causes the missing Bragg peaks in energy-dispersive data.

Shear-driven instability in zirconium at high pressure and temperature and its relationship to phase-boundary behaviors

“…Similar to previous studies [7,30], • ), but further heating results in loss of the pattern features and the emphasis of an amorphous appearing background signal. Additionally, the top panel of (a) shows an zoomed version of the lower pattern in red.…”

“…However, the actual phase boundary is quite difficult to pin down, as evidenced by many works [5,7,17,18,[23][24][25][26][27][28][29], where the prime difficulty is wide α − ω coexistence. Other interesting features exhibited include high pressure-temperature amorphous phases [7,30] and phase boundaries that exhibit possible kinks [7,27] (i.e., change from positive to negative dT/dP phase boundary slope). This report presents high pressure-temperature studies on zirconium in the range up to 7 GPa and 1400 K using UT and simultaneous x-ray diffraction and radiography.…”

Hydrostatic Compression Behavior and High-Pressure Stabilized β-Phase in γ-Based Titanium Aluminide Intermetallics

“…Deformation of the same material at 1493 K in the (α + β + γ)-phase field leads, qualitatively, to the conclusion that β is the actively deforming phase, while α and γ grains display greater stiffness [79]. This high kinetic activity of the β-phase is due to phonon softening, relating to extremely high self-diffusion, in the relatively open bcc lattice [47,80]. This results in rapid dynamic recrystallization, recovery and grain growth, which in essence, eradicates almost any deformation texture of this phase [7].…”

“…Because excessive grain growth in titanium alloys becomes a serious problem at very high temperature, a powder diffraction experiment might degenerate into a study of single crystals if the experimentally-accessible reciprocal space volume is collimated [47]. Moreover, studies of microstructural evolution, allowing for the segregation of the elements in a multi-phase field, such as the co-existing γ-and α 2 -phases in titanium aluminides, require larger sample volumes.…”

<I>In Situ</I> X-ray Diffraction Measurements of Aluminum Pulverization prior to the Hydrogenation Reaction

“…We employed the ADX method because the energy dispersive (EDX) method, which is the standard technique for high-pressure experiments using a multianvil press, was unsuitable to monitor changes of grain sizes of specimens. 12) Two-dimensional diffraction images were recorded using a combination of an imaging plate and cubic boron nitride pistons. For EDX measurements, six pistons made of tungsten carbide squeezed the cubic pressure media, and the specimen was pressurized.…”