Cooling-rate dependence of the density of Pd₄₀Ni₁₀Cu₃₀P₂₀ bulk metallic glass

The effect of cooling rate on the density of the Pd₄₀Ni₁₀Cu₃₀P₂₀ bulk metallic glass (BMG) have been investigated by over the cooling rate range from 0.63 to 500 K/s. The cooling rate dependence of density, microhardness and thermal properties of the BMG is determined. Based on the thermal-expansion coefficients measured in the amorphous and supercooled liquid states, respectively, it is deduced that the density of the BMG in the "ideal" state approaches that of its crystalline counterpart. The effect of cooling rate on the density is discussed in terms of structural relaxation.