Nanostructured composites in multicomponent alloy systems

A group of novel nanostructured composites fabricated by different casting methods is presented. Nb, Ta and Mo are added into Ti-base bulk metallic glass (BMG)-forming alloys and Nb is added to the Zr-base BMG-forming alloy to induce the formation of dendrite/nanostructured matrix composites. These composites exhibit high fracture strength of up to 2400 MPa. Both Nb-bearing Ti- and Zr-base composites exhibit over 14% plastic strain upon room temperature compression. The Ti60Cu14Ni12Sn4Nb10 composite also exhibits over 7% room temperature tensile plastic strain. The high strength of the composites is attributed to the nanostructured matrix. The large plasticity is due to the retardation of excessive localized shear banding in the matrix by the presence of the ductile dendrites. The significant work hardening before fracture is attributed to the deformation behavior of the dendritic solid solution.