Patent ID: 8523045

Claim:
A method of forming a solid-state weld between a first joining surface of a first copper workpiece and a second joining surface of a second copper workpiece; the method comprising: preparing an assembly of the first and second copper workpieces with their first and second joining surfaces aligned surface-to-surface and separated with an interposed layer of reactive copper alloy material, the composition of the copper alloy material being selected to melt and react with surface material of each of the copper workpieces at a temperature below the melting point of either of the first and second copper workpieces; pressing opposing electrical resistance heating electrode members against the first and second copper workpieces to press the first and second joining surfaces against the reactive copper alloy material and for electrical resistance heating of the reactive copper alloy material by passing an electrical current through the workpieces and reactive material at the first and second joining surfaces of the workpieces, the opposing electrical heating electrode members having textured surfaces for contacting the first and second copper workpieces and for reducing the electrical resistance at the contacts of the textured surfaces with the first and second copper workpieces, the textured surface of each electrode member being characterized by peak-to-peak roughness of no less than ten micrometers and no more than ten-percent of the thickness of the copper workpiece at the region of its contact; electrical resistance heating the layer of reactive copper alloy material as it is engaged by the first and second joining surfaces for a predetermined time for the reactive copper alloy material to react with material at the joining surfaces of the copper workpieces and to form a liquid-containing reaction product; the pressure on the assembly acting to force substantially all thus-formed liquid reaction product from between the residual first and second joining surfaces; and, thereafter holding the first and second joining surfaces against each other until a solid-state welded joint is formed coextensively with the joining surfaces.