Synchrotron X-rays reveal elemental Zr and Ti bulk metallic glass as phantom

Scientists at the Japan Atomic Energy Agency (JAEA) led by Dr W. Utsumi have proved that the formation of bulk metallic glass of elemental Zr and Ti, which was recently reported (see for example, Zhang and Zhao, Nature 430, 332 (2004) and Y. Wang et al., Phys. Rev. Lett. 95, 155501 (2005)) was some sort of phantom. The experiment basically took the form of X-ray diffraction in high-temperature and high-pressure conditions, but in addition to the normal energy-dispersive detector, the research group employed an in situ angular-dispersive X-ray diffractometer equipped with a 2D detector and X-ray transparent anvils. The disappearance of all the Bragg peaks in the one-dimensional energy-dispersive data could be taken as evidence of amorphization. However, the research group found several intense Bragg spots in their angular-dispersive data, even in the exact same conditions where amorphization was reported. This indicates that Zr and Ti do not form glass, but that the grains grow rapidly. The experiments were carried out at BL14B1 and BL22XU, SPring-8, Japan. For more information, see the paper, "Does Bulk Metallic Glass of Elemental Zr and Ti Exist?", T. Hattori et al., Phys. Rev. Lett., 96, 255504 (2006).