Achieving Synchronous Improvement in Mechanical Properties and Softening Resistance of Cu-Cr Alloys by Introducing Ta

Cu-0.6 at.%Cr (Cu-Cr) and Cu-0.6 at.%Cr-0.6 at.%Ta (Cu-Cr-Ta) alloys were prepared by mechanical alloying combined with spark plasm sintering. The effective refinement of the microstructure along with the significantly increased dislocation density in Cu-Cr alloy is achieved through the introduction of Ta. Most precipitates transform from Cr precipitates into Cr₂Ta Laves phases with semi-coherent interfacial structure, which provides the effective inhibition effect to dislocation movement and grain coarsening, along with significantly enhanced mechanical properties. Compared with Cu-Cr alloy, 25% and 24% enhancement for the yield strength (413 MPa) and ultimate tensile strength (497 MPa) is realized by Cu-Cr-Ta alloy along with the acceptable elongation of 13.1%. It is worth noting that the significant improvement for high-temperature mechanical properties is also realized through the introduction of Ta, showing the 130% and 124% enhancement of yield strength and ultimate tensile strength at 450 °C, respectively. The softening temperature of Cu-Cr-Ta alloy reaches 1015 °C, which is 16% higher than that of Cu-Cr alloy (876 °C). This study provides an effective approach to improve the mechanical properties and softening resistance of the traditional Cu-Cr alloys under the elevated temperature environment, which has a great potential application in the field of future fusion reactor.