Lowering critical cooling rate for forming bulk metallic glass

Small volumes of Pd44Ni10Cu26P20 and Pd43.2Ni8.8Cu28P20 were encapsulated in B2O3 and thermally cycled between T-g-60 degrees C and T-l+60 degrees C, where T-g and T-l denote the alloys' glass transition and liquidus temperatures. After this thermal treatment, the critical cooling rates (CCRs) for glass formation can be lowered by an order of magnitude, resulting in a critical cooling rate significantly lower than that reported for any other glass forming alloy melt. These experiments demonstrate that the CCR is not constant but strongly dependent on the degree of heterogeneous nucleation.