Welding light metal workpieces by reaction metallurgy

摘要

Aluminum alloy workpieces and/or magnesium alloy workpieces are joined in a solid state weld by use of a reactive material placed, in a suitable form, at the joining surfaces. Joining surfaces of the workpieces are pressed against the interposed reactive material and heated. The reactive material alloys or reacts with the workpiece surfaces consuming some of the surface material in forming a reaction product comprising a low melting liquid that removes oxide films and other surface impediments to a welded bond across the interface. Further pressure is applied to expel the reaction product and to join the workpiece surfaces in a solid state weld bond.

主权项

1. A method of forming a solid-state weld between a first joining surface of a first light metal alloy workpiece, the light metal being aluminum or magnesium, and a second joining surface of a second light metal alloy workpiece; the method comprising:
selecting, as a reactive material, a metallic element, or an alloy of two or more elements, or a mixture of two or more different elements or alloys, in a form to be placed between and in contact with the first joining surface and the second joining surface, the reactive material being selected to react with at least the first light metal alloy joining surface upon being heated to a temperature below the solidus temperature of the first light metal alloy to form a reaction product comprising a liquid comprising the reactive material and the light metal alloy element, and cavities are provided in one of the joining surfaces to hold the reactive material; the following steps being conducted at ambient conditions, preparing an assembly of the workpieces with their respective joining surfaces face-to-face and with at least one of the joining surfaces in contact with the reactive material, the amount of reactive material being predetermined to consume a specified amount of one or both workpieces in forming the reaction product; pressing the assembly at a first pressure level so that the facing surfaces engage the reactive material, and heating the reactive material for a predetermined time to form the reaction product and consume portions of the facing workpieces, including consumption of surface alloy material defining the cavities; increasing the pressure on the assembly to a higher pressure level to force substantially all formed reaction product from between the residual joining surfaces while limiting the displacement of the joining surfaces to a predetermined value; and, thereafter holding the joining surfaces against each other until a solid-state welded joint is formed substantially coextensively with the intended joining surfaces.