The indentation size effect in Pd₄₀Cu₃₀Ni₁₀P₂₀bulk metallic glass

The indentation size effect (ISE) in Pd40Cu30Ni10P20bulk metallic glass was investigated through instrumented nanoindentation under different applied loads. It was found that both the indentation hardness and the reduced contact modulus decrease with an increase in the indentation depth. The ISE is more pronounced in the relaxed alloy than in the as-cast ones. Pop-in events and the subsurface shear band patterns underneath the nanoindenter are also observed to be sensitive to the depth of penetration. The ISE was discussed in terms of strain-induced softening and friction that is related to the ratio of the surface area to volume.