Formation of the aluminum-manganese bronze microstructure during wire-feed electron beam additive manufacturing by applying ultrasound to the melt pool
摘要
The effect of a low-power ultrasonic treatment on the microstructure of the CuAl9Mn2 aluminum-manganese bronze during its wire-feed electron beam additive manufacturing is demonstrated. It is revealed that a dendritic structure forms in the as-printed samples, based on a solid α‑solution, with the needle-like β’-phase precipitating along the grain boundaries. The ultrasound applied to the sample during printing does not significantly alter its phase composition, but reduces the lamellar spacing in the solid α solution and β’ phase. The tendency to forming the columnar grains elongated in the heat dissipation direction is minimized. However, an improvement of the mechanical properties remains relatively modest, manifested primarily by a slightly increased strength and a reduced ductility.