Improved mechanical behavior of bulk metallic glasses containing in situ formed ductile phase dendrite dispersions

In this paper, X-ray diffraction, microstructural, and mechanical property results are presented for a ductile metal reinforced bulk metallic glass (BMG) matrix composite based on Zr–Ti–Cu–Ni–Be bulk glass forming compositions. Solute partitioning in the molten state yields an equilibrium microstructure consisting of ductile Ti–Zr–Nb β-phase primary dendrites, with the b.c.c. structure, in a Zr–Ti–Nb–Cu–Ni–Be BMG matrix. Under mechanical loading highly organized shear band patterns are formed throughout the sample, where the shear band spacing is coherent with the periodicity of the dendrites. This dramatically increases the plastic strain to failure, impact resistance, and toughness of the material. These results are the first to show how microstructural inhomogeneities can be used to control the initiation and propagation of localized shear bands in metallic glasses under a variety of unconstrained loading conditions.