Microstructure and high-temperature mechanical properties of Cu-W composite prepared by hot isostatic pressing

In current work, Cu-20wt%W (Cu-20W) composite of near theoretical density (99.69 %) and high electrical conductivity (86.78 %IACS) was fabricated by spray drying technique and hot isostatic pressing (HIP), aiming to enhance the mechanical properties of Cu-W composite while maintaining high conductivity. The impacts of W nanoparticles on the microstructure and properties of Cu-20W samples were evaluated. Adding W nanoparticles can remarkably refine the grain of Cu and strengthen the Cu-W composite through a pinning effect. Room temperature tensile strength and compressive yield strength of Cu-20W composite were 380 MPa and 304.49 MPa, which are 117.14 % and 616.95 % higher than that of pure Cu (175 MPa and 42.47 MPa), respectively. Tungsten nanoparticles can promote the high-temperature reliability of Cu-W samples. Tensile strength of pure Cu and Cu-20W sample gradually decreased with increasing test temperature, but the percentage increment of tensile strength increased. The tungsten particles pinned at grain boundaries during hot deformation inhibit recrystallization grain growth and hinder dislocation movement, thereby contributing to the high-temperature properties of Cu-20W composite. The peak stress of Cu-20W sample is 146.60 % higher than pure Cu, even at close to the melting point of Cu (940 °C). The strength of Cu-20W composite is heightened by combining fine-grain strengthening and dispersion strengthening due to the introduced W nanoparticles.