Fabrication, thermal stability and mechanical properties of porous bulk glassy Pd-Cu-Ni-P alloys

Porous Pd42.5Cu30Ni7.5P20 glassy alloy rods with diameters of 7 and 10mm and a length of about 20mm were produced by water quenching the mixture of Pd42:5Cu30Ni7.5P20 liquid and solid salt phases at a volume fraction ratio of 7 to 9, followed by leaching treatment into water to eliminate the salt phase. The pores had a polyhedral shape with sizes of 125 to 250 mum. The densities were 3.3 and 4.2 Mg/m(3) and their pore fractions were evaluated as 65 and 55% for the 7 mm and 10 mm rods, respectively. The thickness of the cell walls was in the range of 50 to 250mum. No crystalline phase was observed in the outer surface region as well as in the cell wall region. The glass transition temperature and crystallization temperature of the porous alloy rods were 578 and 679 K, respectively, in agreement with those of the pore-free alloy. Final rupture was not recognized for the porous alloys subjected to the uniaxial compressive test. The porous alloy exhibited lower Young's modulus, lower yield strength, much higher absorption energy, being significantly different from those for the pore-free glassy alloy rod. The unique mechanical characteristics combined with high absorption energy ability indicate the possibility of future uses as a new type of structural and functional materials.