Abstract: Laser powder bed fusion (LPBF) is a promising method for manufacturing functional and structural inte-grated Cu-Cr-Zr components. However, the LPBF-processed Cu-Cr-Zr alloys still suffer from the strength-ductility trade-offdilemma, while maintaining high conductivity. Here, LPBF-processed Cu-Cr-Zr alloy with a hierarchical structure was obtained by increasing the Cr and Zr content simultaneously. After ag-ing treatment, the hierarchical structure was composed of melt tracks at the macroscale, coarse grains (31.9 ±0.1 μm) and fine grains (5.6 ±0.2 μm) at the microscale, high-density of dislocations and dual precipitates at the nanoscale. The direct aged sample exhibited an excellent combination of strength and ductility (tensile strength was enhanced to 626 ±1 MPa and uniform elongation of 16.2 % ±1.1 %), which is superior to the traditionally wrought and LPBF-processed Cu-Cr-Zr alloys reported previously. Meantime, a good electrical conductivity of 71.1 % ±0.3 % IACS was also achieved. In addition, the hetero-geneous deformation-induced stress caused by the hierarchical structure not only led to a large increase in yield strength but also promoted tensile ductility.

Key words: Additive manufacturing, Cu-Cr-Zr alloy, Laser powder bed fusion, Hierarchical structure, Strength-ductility synergy