The well-balanced strength and conductivity in additively manufactured CuCrZr-Y2O3 composites by regulating multi-scale heterostructures

Abstract

As the key properties of copper alloys, achieving high strength and high conductivity are contradictory. Therefore, balancing strength and electrical conductivity is essential in optimizing the properties of copper alloys. This paper presents a detailed investigation into the evolution of multi-scale heterostructures and the properties of CuCrZr-Y₂O₃ composites prepared by additive manufacturing during the annealing process. The multi-scale heterostructures, including grain size and cellular dislocation substructure, demonstrated no significant changes during the annealing process, which occurred from low to high temperatures. Following low-temperature aging treatment of the CuCrZr-Y₂O₃ composites, the formation of fine particles, including the Cr phase, Cu₄Zr phase and YCrO₃ phase particles, was observed. In comparison to the as-built and high-temperature annealed samples, the low-temperature aged samples exhibited the optimal combination of hardness (204 ± 10 HV), electrical conductivity (83.5 ± 0.7 %IACS) and strength (589 ± 10 MPa). The precipitation of solid solution atoms and the formation of the fine particles enhance the Orowan strengthening mechanism and improve the conductivity. This study precisely modifies the multi-scale heterostructures of the CuCrZr-Y₂O₃ composites, offering novel insights into the electrical conductivity behavior and strengthening mechanisms.