Surmounting the thermal processing limits: Patterning TiZrCuPdSn bulk metallic glass even with nanocrystallization

Ni-free Ti-based bulk metallic glasses (BMGs) are promising for biomedical applications, thanks to their excellent biocompatibility and high corrosion resistance. BMGs can be shaped and patterned by viscous flow deformation using thermoplastic net-shaping. This work presents a novel strategy for thermoplastic net-shaping of Ti₄₀Zr₁₀Cu₃₄Pd₁₄Sn₂ BMG. Instead of operating for a short time slightly above the glass transition temperature to avoid crystallization, the proposed method accepts the formation of nanocrystals and makes use of the lower viscosity of the supercooled liquid when processing above the glass transition temperature. Following this approach, Ti₄₀Zr₁₀Cu₃₄Pd₁₄Sn₂ BMG is deformed from a rod to a thin disk, and patterns scaling from 5 μm to 300 μm are successfully created on the Ti-BMG surfaces, demonstrating the potential to create complex features for functional materials. Furthermore, after the thermoplastic net-shaping treatment, the Vickers hardness increases by 6% while the corrosion and passivation current density decrease by an order of magnitude. This work reveals that the BMGs can still be deformed and patterned via the thermoplastic net-shaping technique if the first crystallization event of the BMG systems is the formation of nanocrystals. Most importantly, this work reveals the possibility of processing a broad family of mediocre glass-forming systems and semi-crystalline composites via thermoplastic net-shaping.