Advanced mechanical properties of nickel-aluminum bronze/steel composite structure prepared by wire-arc additive manufacturing

To explore whether a copper-steel composite structure can replace cast nickel-aluminum bronze (NAB), the microstructure and mechanical properties of an arc deposited NAB/steel composite structure were systematically studied. The results demonstrate that in the composite structure, the precipitation of the rosette-like jI phase was inhibited, and the sizes of the a-Cu and j phases were finer than those of the as-cast NAB. The texture density of the NAB layer was lower than that of as-cast NAB. The metallurgical layer dominated by Fe3Al formed at the copper-steel interface improved the strength of the composite structure. Compared with as-cast NAB, the yield strength and hardness of the composite structure increased by 51% and 30%. The Young's moduli of the a-Cu and b phases were higher than those of the ascast NAB. The tensile cracks of the alloys were distributed around the j phase and in the b phases. In the composite structure, the copper-layer cracked first and then extended to the copper-steel interface along with the b phase. Finally, the interface failed, and the copper-steel peeled off. In the tensile specimen, the j phase was surrounded by dislocations and a large number of stacking faults and twins were generated. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-NDlicense