Structure and method of bonding copper and aluminum

A method of bonding an aluminum workpiece to a copper workpiece via an arc welding process including a welding wire, the method comprising:

• applying a first coating to at least a portion of the copper workpiece, the first coating being made of a material having a lower melting point than copper;
• positioning the copper workpiece and the aluminum workpiece with respect to each other to form at least one joint where the two workpieces are to be bonded;
• and
• welding the aluminum workpiece to the copper workpiece along the at least one joint via the arc welding process such that the aluminum workpiece is melted and fused, and the copper workpiece is wetted and brazed along the at least one joint;
• wherein the arc welding process involves a cyclic alternating of a first stage, in which an electric current is supplied to the welding wire as it is moved toward the workpieces, and a second stage, in which the electric current is reduced and the welding wire is moved away from the workpieces, to generate and detach a plurality of molten droplets along the at least one joint, the molten droplets being formed from the welding wire in the first stage.

A bonded structure of copper and aluminum, the structure comprising:

• a first metallic workpiece made of copper;
• a first coating applied to at least a portion of the first metallic workpiece, the first coating being made of a material having a lower melting point than copper;
• and
• a second metallic workpiece made of aluminum, the second metallic workpiece being positioned with respect to the first workpiece to form at least one joint where the two metallic workpieces are bonded;
• wherein the first metallic workpiece and the second metallic workpiece are bonded via an arc welding process including a welding wire such that the first metallic workpiece is wetted and brazed, and the second metallic workpiece is melted and fused along the joint;
• and
• wherein the arc welding process involves a cyclic alternating of a first stage, in which an electric current is supplied to the welding wire as it is moved toward the workpieces, and a second stage, in which the electric current is reduced and the welding wire is moved away from the workpieces, to generate and detach a plurality of molten droplets along the at least one joint, the molten droplets being formed from the welding wire in the first stage.