Warm negative incremental forming of magnesium alloy AZ31 Sheet: New lubricating method

摘要

The present study has been undertaken in order to investigate the suitable lubricants and lubricating methods, which can be employed to form a magnesium alloy AZ31 sheet by warm negative incremental forming (NIF). For the intended purpose, Nano-K_2Ti_4O_9 whisker and organic binder were employed to improve the bonding strength at lubrication coating/sheet interface and lubricating properties at elevated temperatures. The Nano-K_2Ti_4O_9 whisker enhanced solid lubrication film and the solid graphite or MoS_2 powder-coated porous ceramic coatings by pulsed anodic oxidation (PAO) almost have the same coefficient of the initial friction about 0.07-0.1 at room and elevated temperatures, which was satisfied with friction and lubrication condition of warm incremental forming (IF) of the metal sheet. Solid graphite or MoS_2 powder-coated ceramic coatings possessed the remarkable lubrication and self-lubrication effect. These suggested lubricating methods gave an excellent solid lubrication performance and good surface quality of the formed parts in warm IF process of the metal sheet.