US Patent 7509738 Solid-free-form fabrication of hot gas valve discs

A hot gas valve disc for a divert and attitude control disc switching element used in a propelled craft. The hot gas valve disc comprises a first layer comprising a first metal material having a first grain size and a first grain orientation, and at least one additional layer comprising a second metal material having a second grain size that differs from the first grain size, or a second grain orientation that differs from the first grain orientation. A method of manufacturing the hot gas valve disc comprises the steps of fabricating a first metal layer using a solid-free-form fabrication process, the first metal layer having a set of grain characteristics comprising grain size and grain structure, followed by heating the first layer and thereby changing at least one of the grain characteristics.