Thermal stability and high-temperature mechanical performance of nanostructured W–Cu–Cr–ZrC composite

Abstract

Improvement of high-temperature mechanical properties of W–Cu based composites is highly desirable but still a challenge. Here it is achieved by combined effects of solid solution, dispersed nano-precipitation and highly stabilized nanostructure in the W–Cu–Cr–ZrC composite, which takes advantage of the in-situ precipitated Zr–Cr–C nanoparticles and phase-separated Cr thin films. The grain size of W phase in the W–Cu–Cr–ZrC composite retained at the nanoscale up to 1000 °C (close to Cu melting point) for a long duration. The high thermal stability of the nanostructure endows the composite with a compressive strength of 1150 MPa at 900 °C, which is approximately four times as high as that of the binary coarse-grained W–Cu composite. The effects of microstructure evolution on the mechanical properties at high temperatures and its mechanisms were disclosed. The results indicated the crucial role of the microstructural stability of W phase skeleton in the overall strength of the W–Cu based composites.