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

Abstract

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 κI phase was inhibited, and the sizes of the α‐Cu and κ 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 α‐Cu and β phases were higher than those of the as‐cast NAB. The tensile cracks of the alloys were distributed around the κ phase and in the β phases. In the composite structure, the copper‐layer cracked first and then extended to the copper‐steel interface along with the β phase. Finally, the interface failed, and the copper‐steel peeled off. In the tensile specimen, the κ phase was surrounded by dislocations and a large number of stacking faults and twins were generated.

Keywords

• Nickel‐aluminum bronze
• Composite structure
• Mechanical properties
• Wire‐arc additive manufacturing