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 . 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  as part of the MRSEC IRG-3 effort. The work is described in Ref.