Does bulk metallic glass of elemental Zr and Ti exist? 
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.