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

Equal-channel angular extrusion is used to consolidate a blend of amorphous Zr_56.3Nb_5.1Cu_15.6Ni_12.9Al_10.0 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° 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° to 68°, 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° to the direction of loading is not predicted by all of the models. Foams with pores aligned 24–68° 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.