The Microstructure and Mechanical Properties of High-Strength 2319 Aluminum Alloys Fabricated by Wire Double-Pulsed Metal Inert Gas Arc Additive Manufacturing

Using double-pulsed melt inert-gas welding (DP-MIG)-based wire arc additive manufacturing (WAAM), the 2319 aluminum alloy components were fabricated with different pulse frequencies. The low-frequency pulses with 1, 3 and 5 Hz were used to deposit thin-wall parts. The scanning electron microscopy (SEM) and optical microscopy (OM) were used to observe the microstructure and fracture surface; the EDS was performed to identify the precipitation phase. The tensile properties were carried out along vertical direction and horizontal direction. The results show that the theta and theta ' phases were found in the deposition part. As the low frequency increases, the equiaxed size in the inner layer region decreases and promoted the precipitation of the theta phase. By changing the low-frequency pulse from 1 to 3 Hz, the ultimate tensile strengths and the elongations in the horizontal as well as vertical the directions increase by 25.67, 19.46 MPa, 0.36 and 4.59%, respectively. The maximum tensile strength reached 253.18 MPa when the pulse frequency was 3 Hz. A large number of dimples were observed on the fracture surface for different pulse frequencies, indicating that the fracture modes of different frequencies were mainly ductile fracture.

Automated summary

By using DP-MIG-based WAAM, 2319 aluminum alloy components were fabricated with different pulse frequencies, resulting in improved tensile properties and microstructure, enhancing the material's strength and ductility.