Plasticity enhancement in bulk metallic glasses by electroless plating with Ni-P amorphous films

• Electroless plating is used to deposit Ni-P films on Zr-based bulk metallic glasses with different pH values and thicknesses.
• The special structure exhibits plasticity to 10.6 %, and it is without obvious sacrifice of the yielding strength.
• The amorphous Ni-P films provide high radial confinement stress, which leads to the formation of multiple shear bands.

In this study Electroless plating is used to deposit amorphous Ni-P films on the surface of the Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit.1) bulk metallic glasses (BMGs) with different pH values and film thicknesses. The special amorphous/amorphous structure exhibited large plasticity. The plastic strain is 10.6% for the coated pillars with a coating thickness of 86.5 μm, which is 5.9 times of 1.8% of the bare Vit.1 pillars. The amorphous Ni-P films provide high radial confinement stress, which leads to more homogeneous formation of a high density of smaller shear bands at the Ni-P/Vit.1 interface. The technique provides an effective way to enhance the plasticity without obvious sacrifice of the yielding strength for BMGs at room temperature.