A method of forming a high strength copper alloy. The method comprises heating a copper material including from about 2 wt. % to about 20 wt. % manganese by weight of the copper material to a temperature above 400° C., allowing the copper material to cool to a temperature from about 325° C. to about 350° C. to form a cooled copper material, and extruding the cooled copper material with equal channel angular extrusion to form a cooled copper manganese alloy.