Impact of Interpass Temperature on Properties of Aluminum ER2319 Produced by Wire Arc Additive Manufacturing With a Weave Path

Abstract Casting of large structural components, while common, can be challenged by months-long lead times. Large format wire arc additive manufacturing is a promising alternative manufacturing solution that can address this challenge and create a more flexible and resilient supply chain. For large-scale applications, controlling the arc path and interpass temperature is important for improved part quality and manufacturing productivity. The goal of this paper is to investigate the impact of interpass temperature under a weaving path profile for the ER2319 wire aluminum alloy on manufacturing productivity and longitudinal mechanical properties. In this work, a “sine wave” weave path was utilized to produce demonstration walls by wire arc additive manufacturing using gas metal arc welding. While the instantaneous arc conditions were like prior investigations, the weave path resulted in a net heat input of approximately 900 J/mm, significantly higher than historic reports under comparable deposition conditions. Two walls were produced with target interpass temperatures of 150 and 200 °C each. Walls were sectioned and one half of each wall was solutionized, quenched, and aged at 175 °C for 3 hr. In both the as-deposited and heat treated conditions mechanical properties were tested parallel to the deposition direction and cross-sections were analyzed with optical microscopy. Porosity was measured using the volumetric displacement method for relative specific gravity, while area fraction of pores was also measured using optical microscopy. High quality walls were produced, with overall porosity below 1 % by volume. Interestingly, the interpass temperature variation is found to have no statistically significant impact on the mechanical properties in the longitudinal direction in either the as-deposited or heat treated condition, suggesting that the sine wave weave deposition path results in a process window that is robust to in-process variations of interpass temperature and that productivity can be significantly improved without sacrificing mechanical strength. As expected for ER2319 alloy, heat treat resulted in a significant increase in strength for both interpass temperature conditions. Comparing to prior literature, the resultant part quality, as measured by porosity, is better than several prior reports. However, mechanical strength in the weave-deposited WAAM walls is lower than prior reports in ER2319 produced at similar arc conditions but different path strategies. These findings underscore that deposition conditions are important for both WAAM quality and mechanical performance.