Abstract
Al-Cu alloy made by arc fuse additive has excellent microstructure and properties, but the difference between transverse and longitudinal is the key factor limiting its application.In this experiment, Al-Cu alloy deposits with different Cu contents were formed by the wire + arc additive manufacturing (WAAM) process used Al-Cu welding wire with different Cu content.The microstructure and properties of the deposits,both intralayer and interlayer,were analyzed using metallography, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and tensile tests.The results showed that the interlayer content of Cu is higher than that in the intralayer. When Cu content in the deposit was 6.3% in the as-deposited state, there was an enhanced θ (Al2Cu) precipitate phase in the interlayer position. After T4 treatment, there were still θ phases with a size larger than 20 µm, which were linearly distributed parallel to the accumulation layer. These θ phases led to lower mechanical properties in the vertical direction than in the horizontal direction, with a brittle fracture mode. When the Cu content of the deposit was reduced to 5.6% after T4 treatment, there were no large θ phases in the interlayer position. Furthermore, the mechanical properties of horizontal and vertical directions were consistent, and they had a ductile fracture mode.The Cu content in the deposit was the primary reason for the difference in mechanical properties between horizontal and vertical directions. Al-Cu alloy deposits with uniform mechanical properties in the horizontal and vertical directions can be obtained by controlling the Cu content,which has an important role in the application of this process.