Formation of porous Pd-based bulk glassy alloys by a high hydrogen pressure melting-water quenching method and their mechanical properties

Porous glassy Pd42.5Cu30Ni7.5P20 alloy rods of 7 mm in diameter and 50 mm in length were produced by melting the Pd-Cu-Ni-P alloy for 600 s at 853 K in a hydrogen pressure of 1.5 MPa and then water quenching. The pores have a nearly spherical shape and their average size is approximately 200 mum. The volume fraction of the pores was changed in the range of 0.36 to 0.64. The glass transition temperature and crystallization temperature of the porous alloy are 577 and 671 K, respectively, in agreement with those of the pore-free alloy. The porous alloy rod exhibits unique mechanical properties with the features of much higher ductility and flexibility which are significantly different from those for the pore-free alloy rod. The unique mechanical characteristics indicate the possibility of future uses as a new type of structural and functional materials.