Bulk Metallic Glasses

Metallic glasses are attractive candidate materials for kinetic energy penetrators because shear localization is the dominant deformation and failure mode at high rates, achieving the desired “self-sharpening” penetration behavior. The penetration behavior of amorphous alloys rivals that of depleted uranium when normalized to alloy density, but they lag in absolute performance due to their low density. Although some improvements in alloy density have been made, it seems clear that effective penetrators will have to be based on materials consisting of crystalline particles of a high-density metal (to increase density) embedded in an amorphous metallic matrix (to promote shear localization). These metallic-glass-matrix composites (MGMCs) have the added advantage of providing additional microstructural parameters for tailoring mechanical properties such as strength and plastic deformation, while retaining the desired shear localization under dynamic deformation.

 Long-Range Objectives

· Determine the mechanism by which ductile, crystalline second-phase particles initiate or control shear bands in MGMCs, and how they influence shear band propagation under both quasi-static and dynamic loading.

· Determine how the microstructure of MGMCs (particle volume fraction, size, shape, and nature of the particle/matrix interface) influences macroscopic mechanical behavior.

ZrCuNiTaAl MGMC containing Ta particles

Metallic Glass Matrix Composites

CRG