Journal of Materials Research

Rapid Communications

Doubling the Critical Size for Bulk Metallic Glass Formation in the Mg–Cu–Y Ternary System

H. Maa1, Q. Zhenga1, J. Xua1 c1, Y. Lia2 and E. Maa3

a1 Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People’s Republic of China

a2 Department of Materials Science and Engineering, National University of Singapore, Singapore 117675, Singapore

a3 Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, Maryland 21218


Mg−Cu−Y alloys with optimal glass forming ability have been found at off-eutectic compositions. The critical size for bulk metallic glass formation at the pinpointed compositions more than doubles that of the previously discovered eutectic Mg65Cu25Y10 alloy, leading to fully glassy rods with near-centimeter diameters in the ternary system upon copper mold casting. The result is a striking demonstration of the strong composition dependence of the glass forming ability, as well as of the need to scrutinize off-eutectic compositions. The implications of the discovery are discussed.

(Received May 11 2005)

(Accepted June 07 2005)

Key Words:

  • Alloy;
  • Metallic glass;
  • X-ray diffraction (XRD)


c1 Address all correspondence to this author.e-mail: