Formation and mechanical properties of porous Pd-Pt-Cu-P bulk glassy alloys

Porous Pd ₃₅Pt ₁₅Cu ₃₀P ₂₀ bulk glassy alloy rods were prepared by holding the alloy melts under 1 MPa hydrogen atmosphere, followed by water quenching in reduced hydrogen pressures of 0.9 or 0.1 MPa. The volume fraction and size of pores were controlled by hydrogen pressure of the atmosphere. No crystalline phase was observed over the whole pore wall regions. The porous alloys show slightly decreased thermal stability as compared with the pore-free one, but still keep a large supercooled liquid region. The porous alloy rods exhibited significant plastic elongations in compression while the pore-free rod fractured instantly after the elastic strain limit. The high plasticity of the porous alloys is presumed to originate from the generation of a high density of shear-bands resulting from the effect of stress concentration around the pores.