A round die hot coextrusion technique used to prepare rods having complex cross sections has been developed and successfully applied to the fabrication of powder metallurgy parts with and without external cladding. The procedure involves assembling and extruding steel billets of round cross section which contain an axially located assembly of powder metallurgy and sheet metal parts which is an enlarged and shortened mockup of the desired part. After extrusion, the steel parts are removed and a fully dense rod having the desired shape and composition remains. Rods having several compositions in metal lurgically joined zones along their lengths can be produced by this method. For example, a Y-shaped rod with a Ti-25 volume per cent Eu2O3 dispersion at one end, a Ti-10.7 volume per cent B10 dispersion midsection, and a pure Ti length at the other end was successfully produced. It showed dimensional uniformity in keeping with usual tolerances for reactor control components and was clad with a fully bonded, 0.005-inch thick layer of titanium. Data on the physical properties, corrosion performance, thermal cycling resistance, and irradiation damage resistance of parts produced by this technique are presented. These data indicate that the method can be successfully used to produce reactor components which are very difficult to manufacture by other techniques.