Patent ID: 8960523
Filing Date: 2015-02-24
Classification: B23K

Abstract:
1. A method of forming a friction stir weld between a magnesium-based alloy workpiece and an aluminum-based alloy workpiece, the method comprising: forming an assembly in which the magnesium-based alloy workpiece and the aluminum-based alloy workpiece have faying surfaces with a faying surfaces weld location at which the friction stir weld is to be formed and one of the workpieces has a surface with a friction stir engagement location for engagement with a rotating friction stir weld tool; placing an interlayer composition at one or both of the friction stir engagement location or faying surfaces weld location, in which the interlayer composition consists essentially of a mixture of an adhesive and silver, tin, and zinc as powder; and friction stirring the magnesium-based alloy workpiece and the aluminum-based alloy workpiece with a friction stir tool that initially engages the friction stir engagement location and penetrates the workpieces to each faying surfaces weld location; in which the action of the friction stir tool causes mixing of the interlayer composition with metal elements of the magnesium-based alloy workpiece and the aluminum-based alloy workpiece and forms a weld material at the faying surfaces weld location, the inclusion of the interlayer composition in the weld material causing the weld material to increase in viscosity and to form a stronger friction stir weld bond between the magnesium-based alloy workpiece and aluminum-based alloy workpiece than a friction stir weld bond formed between the workpieces without the placement of the materials or material combinations; and in which the action of the friction stir tool also causes at least a portion of the adhesive to cure and to bond the magnesium-based alloy workpiece and the aluminum-based alloy workpiece together.