Glass-forming ability and thermoplastic formability of a Pd40Ni40Si4P16 glassy alloy

The glass-forming ability of a Pd 40 Ni 40 Si 4 P 16 alloy has been investigated. This alloy exhibits a wide supercooled liquid region of 107 K, a high reduced glass transition temperature of 0.596 and a small fragility parameter of 28, indicating that this alloy is a good glass former. Using flux treatment, the Pd 40 Ni 40 Si 4 P 16 alloys can be easily produced as centimeter-scale metallic glasses. The glass transition and crystallization kinetics of this alloy were investigated by means of both differential scanning calorimetry (DSC) and differential isothermal calorimetry (DIC). Thermoplastic forming of the Pd 40 Ni 40 Si 4 P 16 glassy alloy is easily performed due to the high thermal stability and low viscosity of the supercooled liquid. By pressing a “flat” silicon wafer onto a sample within the thermoplastic forming region, the surface of the Pd 40 Ni 40 Si 4 P 16 metallic glasses could be significantly smoothened. The final surface showed a reduced root mean square roughness R q as low as ~2 nm. This indicates a simple approach to prepare “flat” surfaces for metallic glasses.