Microstructure and mechanical properties of ductile phase containing bulk metallic glass composites

Ductile phase containing bulk metallic glass composites are prepared and investigated by SEM, X-ray diffraction, microprobe, and demonstrate improved mechanical properties in compression, tensile, and Charpy impact tests. The remarkable glass forming ability of bulk glass forming compositions in Zr-Ti-Cu-Ni-Be system allows for the preparation of ductile metal reinforced composites with a bulk metallic glass matrix via in-situ processing. Primary dendrite growth accompanied by solute partitioning in the molten state yields an equilibrium microstructure containing of a ductile crystalline phase with bcc-structure in a metallic glass matrix with varying volume fractions of bcc-phase and varying scales of the microstructure. The incorporation of a ductile metal phase into a metallic glass matrix yields a constraint that allows for the generation of multiple shear bands and stabilizes crack growth in the matrix. These results increase global plasticity of metallic glass under unconstrained loading condition and increase toughness, impact resistance, and resistance to crack propagation. Sub-standard Charpy specimens prepared from one of these composites have demonstrated impact toughness 300% greater than that of metallic glass matrix alone. Also, the strain to failure in tension is about 5% and 12% in compression.