Other approaches are under development. To reduce fabrication costs, continuous processes such as pultrusion and hot roll bonding are being developed. Three basic methods are being used to make whisker and particulate-reinforced MMCs. The two powder-metal processes differ primarily in the way the constituents are mixed. One uses a ball mill, the other employs a liquid to aid mixing, which is subsequently removed.
Mixtures are then hot pressed into billets.
Secondary processes are similar to those for monolithic metals, including rolling, extrusion, spinning, forging, creep-forming, and machining. The latter poses some difficulties because the reinforcements are very hard.