Low Density Ti-based Bulk Metallic Glasses as a Matrix For High Performance Metallic Glass Composite @ California Institute of Technology

Author(s):

W.L. Johnson

In a recent publication in Nature, we reported bulk metallic glass (BMG) matrix composites exhibiting >10% tensile ductility and Fracture Toughness comparable to or exceeding the toughest metals known [1]. These high performance composites demonstrate the potential of metallic glass as revolutionary structural metals. The BMG matrix composites contain elastically soft dendrites comprised of Ti-Zr-Nb embedded in a glassy matrix. Toughening and ductility are achieved by a mechanism similar to the toughening of plastics by soft inclusions such as rubber. The SEM and TEM work displayed in the Nature publication were carried out using MRSEC supported facilities. In our efforts to further develop these novel structural materials, we have extended the work reported in Nature to new materials containing higher atomic fractions of Ti to produce lighter BMG-composites having the density of commercial Ti-alloys. The new glassy matrix alloys used in these low density composites are a series of novel Ti-rich bulk metallic glasses having very high strengths, high fracture toughness, and densities comparable to that of elemental Titanium. Fig.1 below shows examples of 6-8 diameter rods of three of the new alloys developed by graduate students Gang Duan and Mary Laura Lind [2] as part of the MRSEC IRG-3 effort. The work is described in Ref. [2]

caltech-mrsec-0520565-low-density2.ppt

Related publication(s):

1. Doug C. Hofmann, Jin-Yoo Suh, Aaron Wiest, Mary Laura Lind, Marios Demetriou, and W.L. Johnson, "Disigning Bulk Metallic Glass Matrix Composites with High Toughness and Tensile Ductility", Nature, 451, 1085 (February 28, 2008)
2. Gang Duan, Aaron Wiest, Mary Laura Lind, Annelen Kahl, and W.L. Johnson, "Lightweight Ti-based Bulk Metallic Glasses Excluding Later Transition Metals", Scripta Mater.,58, 465 (2008)