| 摘要 |
A method for making a cast and forged metal article (20), comprising the steps of, a) preparing an expendable pattern of the part to be cast, b) dipping said pattern into slurry of fused silica and a binder to form a moist coating, c) sprinkling silicon carbide grit on said moist coating, d) drying said moist coating, e) repeating steps b), c), and d) until said shell (37) is built up to the desired thickness, and f) casting a metal article (20) in said mold (37) to form a preform blank, and g) subjecting said preform blank to extrusion (14), closed die forging (15), or both, to produce desired mechanical properties and microstructure. The alloy is a cobalt based metal alloy, wherein the carbon content of said cobalt based alloy is above 0.2 % by weight. The final forged workpiece is a hip replacement. A metal-matrix composite comprising a uniform distribution of ceramic particles (31) within a metal matrix (32) formed of a metal having a melting point above 1000 DEG C and a specific gravity of at least 4. The particles (31) are aluminum oxide or zircon. The metal (32) is a stainless steel. |
