Fabricating copper-rich Cu-Al binary alloy by wire-arc additive manufacturing

In response to the needs of increasing the usability of the wire-arc additive manufacturing process(WAAM) and offering an innovative way of producing Cu-Al alloys with controlled chemical compositions, the present research has applied the WAAM process in Cu-Al alloy with targeted 9 at. % Al content on pure copper plates. After overcoming several processing problems such as opening the deposition molten pool on the extremely high-thermal conductive copper plate and conducting the Al wire into the molten pool with very low feed speed, the copper rich Cu-Al alloy has been successfully produced with constant pre-designed Al content above the dilution affected area. Also, in order to homogenize the as-fabricated material and improve the mechanical properties, two further homogenization heat treatments at 800 degrees C and 900 degrees C have been applied. The material and mechanical properties of as-fabricated and heat-treated samples have been compared and analyzed in detail. With increased annealing temperatures, the content of precipitate phases has decreased, and the samples have shown obvious improvements in both strength and ductility with little variation in microstructures. The present research opened a gate for in-situ fabrication of Cu-Al alloy with target chemical composition and full-density using additive manufacturing process.