Microstructure and phases investigations of W–Mo–Cu alloy prepared by large current electric field sintering

Abstract

W–Mo–Cu alloy was fabricated by large current electric field sintering at a low temperature of 950 °C. The interrupted sintering at different sintering stages was performed to identify the phases and microstructure evolution during the densification process. The transmission electron microscope (TEM) images clearly show that the nanoscale phases form and distribute at the boundaries of W, Mo, and Cu phases. Moreover, the high-resolution TEM images incorporating with a selected area fast Fourier transform and inverse fast Fourier transform (IFFT) treatment present the structure of formed phases. Meanwhile, the lattice parameters calculated through X-ray diffraction patterns and IFFT images jointly evidence the existence of defects and atom diffusion during the sintering. The dislocations and lattice strain induced by the ultrahigh current and pressure provide the stored energy and nucleation sites, thus promoting the diffusion of elements and the formation of fine grains.