Preparation of a Zr-based bulk glassy alloy foam

A Zr48Cu36Al8Ag8 bulk metallic glass (BMG) containing spherical pores with 3.9% porosity was prepared by melting a Zr48Cu36Al8Ag8 powder under 1.0 MPa pressurized helium. Annealing treatment of the porous alloy in a supercooled liquid region causes expansion of the pores. Highly porous BMG with a cellular structure was prepared by sudden reduction of the helium pressure in the crucible before quenching. The porous alloys exhibited significant plasticity due to a high density of shear bands initiated from pores.