Microstructure and mechanical properties of 2319 aluminum alloy deposited by laser and cold metal transfer hybrid additive manufacturing

Abstract

Wire and arc additively manufactured aluminum alloys are prone to porosity, leading to poor mechanical properties in samples, which hinders their broad industrial application. Laser and arc hybrid processes have garnered increasing attention for their potential to reduce porosity, stabilize the arc, and enhance deposition efficiency. This paper investigates the porosity, element distribution, microstructure evolution, and mechanical properties of 2319 aluminum alloy produced through the laser and cold metal transfer (laser-CMT) hybrid additive manufacturing process. In comparison with the as-deposited samples, the laser-CMT hybrid process decreases porosity, enhances element distribution, mitigates Cu element segregation, and results in increased θ′′ phase precipitation. Following T6 heat treatment, the ultimate tensile strength (UTS), yield strength (YS), and elongation of the x-direction specimens from the laser-CMT hybrid process are 450.0 MPa, 318.1 MPa, and 10.0%, respectively. These values are 11.27%, 7.03%, and 36.65% higher than those of the as-deposited samples. To validate the findings, a large-scale load-carrying frame for a commercial aircraft was fabricated, demonstrating the efficacy of the process. The paper also presents a detailed analysis of the strengthening mechanism. Samples deposited using the laser-CMT method exhibit reduced porosity and excellent mechanical properties, making this process promising for a wide range of applications.