Extraordinary ductility in the 75W–25Cu composite at elevated temperatures

The high-temperature mechanical properties are an essential indicator in the application of W–Cu composites. In this study, a 75W–25Cu composite with high relative density is prepared by infiltration. Its tensile properties are investigated from 25 °C to 1000 °C, and the fracture strain shows a non-linear trend with a peak value of 20 % at 200 °C. The fracture mode is the ductile fracture of Cu and the combination of the transgranular and intergranular fracture of W at 200 °C. Microstructure characterization of the post-deformed tensile specimens at 25 °C, 200 °C, and 1000 °C is conducted in conjunction with the finite element analysis. The atypical increase of the fracture strain at 200 °C is rationalized through the perspective of dislocation slip in Cu and the stress partitioning between the two phases. The high-temperature mechanical properties of W–Cu composites are summarized at the end for specimens with a range of compositions and fabrication processes. The current work provides a solid basis for any subsequent optimization and potential application of W–Cu composites.