Abstract: The high cutting heat in machining of Zr-based bulk metallic glass (Zr-based BMG) can trigger the crystallization of workpiece materials, which in turn leads to the loss of excellent properties of the BMG. The use of icing clamp to fix workpiece in order to realize the freezing machining of BMG is proposed. The light emission features and associated influencing factors are studied. The effects of freezing cutting parameters, including cutting speeds, feed rates and tool coatings on BMG cutting force are analysed. The high-efficient, precise and non-crystallized processing technology in freezing cutting, is optimized. Also, the wear form for coated tools are revealed. The results show that the light emission in BMG freezing cutting is the primary causes for the machined surface crystallization and high surface roughness. The main factors that cause this phenomenon included high cutting speed, small feed rate and tool wear accumulation with increased cutting length. No light emission is observed when changing tool coatings. Cutting force was mainly affected by cutting speed, but it was not sensitive to feed rate. The failure modes for the four coated tools, TiSiN, TiAlN, CrSiN and AlCrN, are the adhesive wear of flank face, the coating peeling off of rake face and the tool tip chipping. Among them, the CrSiN coating had the best adhesive wear resistance, and can get the minimum cutting force and the best surface quality. By optimizing freezing cutting process, the high-speed milling of Zr-based BMG can be achieved, while avoiding the light emission, and getting high-quality non-crystallized machined surface.

Key words: Zr-based bulk metallic glass, freezing machining, cutting characteristics, non-crystallized processing technology