Pressure effects on a novel W-Mo-Cu alloy by large current electric field sintering: Sintering behavior, microstructure and properties

Abstract

A novel W-Mo-Cu alloy, combining the advantages of W-Cu and Mo-Cu pseudo-alloy, was rapidly prepared by Gleeble thermo-mechanical simulator at a low temperature (975 °C) in a short time (5 min) due to the large current electric field (∼105 A). The effects of pressure (0–40 MPa) on the microstructure and properties of W-Mo-Cu alloys were comprehensively studied. It is proved that pressure contributes greatly to the sintering densification, since the driving force for atoms diffusion improves due to the elevated difference of vacancy concentration between the bulk of the powders and the neck-like zone by loading pressure. Results show that W-Mo-Cu alloys consist of W, Mo, Cu phase and a new phase of Cu0.4W0.6 intermetallic compound. Appropriately increasing the sintering pressure is conducive to optimal microstructure with increased sintering densification, accompanied by increased micro-hardness and decreased electrical resistivity. In particular, after applying a pressure of 35 MPa, the relative density of the sample increases from 80.27% to 95.53%. The present study potentially offers valuable insights and guidance toward the preparation of W-Mo-Cu alloys.