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 r esults are presented for a ductile metal reinforced bulk metallic glass (BM G) matrix composite based on Zr-Ti-Cu-Ni-Be bulk class forming compositions , Solute partitioning in the molten state yields an equilibrium microstruct ure consisting of ductile Ti-Zr-Nb beta -phase primary dendrites. with the b.c,c, structure, in a Zr-Ti-Nb-Cu-Ni-Be BMG matrix. Under mechanical loadi ng highly organized shear band patterns are formed throughout the sample, w here the shear band spacing is coherent with the periodicity of the dendrit es. This dramatically increases the plastic strain to failure, impact resis tance, and toughness of the material. These results are the first to show h ow microstructural inhomogeneities can be used to control the initiation an d propagation of localized shear bands in metallic glasses under a variety of unconstrained loading conditions. (C) 2001 Elsevier Science B.V. All rig hts reserved.