Liquid forging of thin Al–Si structures

Liquid forging is a pressurized solidification process, wherein finished components can be produced in a single process from molten metal to solid, utilizing re-useable die tools. In conventional die casting (gravity and pressure), components with a minimum wall thickness of about 0.6 mm can be fabricated. However, parts with section thickness as thin as 0.2 mm can be liquid forged using near eutectic Al–Si or Al–Si–Cu alloys. Water based lubricant containing micrographite is effective in releasing the component during ejection. In addition, it aids in shaping the component to required dimensional accuracy. These liquid forged parts are pore free. Thermal analysis of liquid forged 0.8 mm plate revealed rapid freezing at the rate of about 700 °C/s. During the process, die and punch were maintained at 200–250 °C. X-ray residual stress analysis on the surface of the liquid forged plate showed high intensity values for 0.1 mm plate. Distribution of eutectic silicon at inter dendritic region is extremely fine to nanoscale level.