Anisotropic mechanical properties of amorphous Zr-based foams with aligned, elongated pores

Equal-channel angular extrusion is used to consolidate a blend of amorphous Zr56.3Nb5.1Cu15.6Ni12.9Al10.0 and crystalline W powders into dense composites. Chemical dissolution of the crystalline phase results in amorphous foams with elongated pores, aligned at a 22-28 degrees angle with respect to the extrusion direction, whose compressive properties are studied for various orientations. As the angle between the pore long direction and the applied stress direction increases from 0 degrees to 68 degrees, there is a significant decrease in loading stiffness and peak stress, as expected from predictive analytical models; however, the observed increase in stiffness and peak stress observed when the pores are oriented 90 degrees to the direction of loading is not predicted by all of the models. Foams with pores aligned 24-68 degrees to the direction of loading show increased plastic bending in individual walls and accumulation in microscopic damage without failure, leading to increased compressive ductility and absorbed energy over other orientations. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.