Formation and utilization of compound billet

摘要: Methods are disclosed for the formation and utilization of a compound billet wherein longitudinally extending inner member, composed first material, is retained firmly within interior hollow, outer second relaxation strain characteristic material greater than material. Such formed by providing blank, element, resides material; applying to longitudinal ends element stress magnitude sufficient cause deform plastically outwardly, perpendicularly direction its extension, such an extent as also extension; then releasing compressive stresses at allowing elements relax inwardly, that tendency toward degree in will grasp exterior element. The this technique may thereafter be extruded through suitable die aperture so produce elongated, product, e.g., copper-clad aluminum wire or busbar.