Microstructural Evolution and Mechanical Properties of 2219 Aluminum Alloy Deposited by Wire and Arc Additive Manufacturing
Abstract
Thin-walled specimens of 2219 aluminum alloy are fabricated at different deposition speeds using the wire + arc additive manufacturing (WAAM) method. The effects of deposition speed on the microstructure, growth rate of columnar grains, and tensile strength of WAAM-printed Al–Cu alloys are investigated. The fraction of columnar grains decreases from 86.7% to 12.2%, and the average grain size decreases from 147 to 65.3 μm as the deposition speed increased. Also, the fraction of θ phase gradually decreases as the deposition speed increased. Specifically, the growth rate of columnar grains varies from 1.02 × 10−3 to 2.05 × 10−3 m s−1, which possesses two orders of magnitude higher than the growth rate of equiaxed grains. With increasing the loading stress, the cracks first form on the dendritic θ phases located at the grain boundaries, reducing the effective loading area. With the deposition speed increased, the typical dimple-like structures are presented at the fracture surfaces, attributing to a decrease in Cu content at the grain boundaries and the producing of the spot-like θ phase inside the matrix. The specimen with a deposition speed of 250 mm min−1 possesses a tensile strength around 274 MPa, and the corresponding elongation reaches to 12.6%.
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Source: Preview Image: Jin, P., Ren, H., Liu, Y. and Sun, Q. (2022), Microstructural Evolution and Mechanical Properties of 2219 Aluminum Alloy Deposited by Wire and Arc Additive Manufacturing. Adv. Eng. Mater., 24: 2101799. https://doi.org/10.1002/adem.202101799