Joining of Dissimilar Materials by the Cold Spray Process

This paper presents a concept to develop a practical method to join dissimilar materials by the cold spray process currently not possible with conventional technologies because of limitations regarding high thermal input, the formation of deleterious intermetallics and/or tensile residual stresses, restrictions on the types of materials that can be joined, extensive fixturing requirements, or is simply economically prohibitive or impractical in production or field use. The novel aspect of the process includes the development of various joint designs and surface preparation methodologies and the incorporation of these into specific sequences of fabrication steps using cold spray as the enabling technology to join dissimilar materials. The emphasis of this presentation will be the joining of cast ZE41A Magnesium and wrought 6061 Aluminum by the cold spray process in combination with friction-stir welding and the subsequent materials characterization. Electron and optical microscopy will be discussed in detail, along with mechanical testing and microstructural analysis. Comparisons will be made to conventional joining techniques.