| 摘要 |
1400624 Casting processes MASSACHUSETTS INSTITUTE OF TECHNOLOGY 16 June 1972 [16 June 1971 31 May 1972] 28274/72 Heading B3F [Also in Divisions C7 and F4] A partially molten metal is agitated by mixer blades, gas-bubbling or electromagnetic stirring to disperse solid particles in the liquid metal and form a viscous slurry. The partially molten metal slurry may be cast into a mould or rapidly cooled to form a slug which comprises dispersed particles of degenerate dendrites in a matrix of solidified metal. The slug upon reheating becomes thixotropic and may be cast by forcing the apparently solid slug into a mould, the shear force causing the slug to flow. The casting of Sn-10% Pb, Cu-10% Sn, Fe-3% C-4% Si and Al-8À5% Si-3% Cu-1% Fe is exemplified. Sn-15% Pb, Al-30% Sn and Al-4À5% Cu can also be employed. Molten Pb may be dispersed in liquid-solid Al alloy to form a composite bearing material. Particulate additives, e.g. graphite, ceramic, sand or foaming agents, e.g. ZrH 2 can be added to the slurry. |
