The Keystone and MSU team propose to demonstrate the feasibility of solid-state joining high strength and temperature alloys utilizing the Thermal Stir Welding process. The alloy selected for this proposed effort is Haynes 230; the alloy of choice typically utilized in rocket engine nozzel skirts. This class of alloys is difficult to fusion weld and has not been shown weldable by friction stir methods. Thus, the Keystone team is proposing to utilize the Thermal Stir Welding process; a solid-state welding process that decouples the stirring and heating features of the process to enable optimization of each key parameter. By independently controlling and optimizing these two process parameters, the best metal working parameters can be identified and utilized to plasticize and stir the Haynes 230 alloy to achieve solid-state welding. Achievement of this objective will enable superior mechanical properties in the weld joint and thus maximize the capability of the weld for the intended application.