Liquid forging of thin Al–Si structures

Abstract: 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 0.6mm can be fabricated. However, parts with section thickness as thin as 0.2mm 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 0.8mm 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 0.1mm plate. Distribution of eutectic silicon at inter dendritic region is extremely fine to nanoscale level. [Copyright &y& Elsevier]