Microstructure and mechanical properties of Mo-Cu-Zr composites fabricated via microwave sintering

Mo–Cu composites exhibit excellent physical and mechanical properties, while the problems of densification and interface seriously limit their application. In this paper, the effect of element Zr on the properties of Mo–Cu composites is investigated aiming to overcome these critical issues. Various compositions of Mo–Cu–Zr ternary composites were fabricated via ball milling, cold isostatic pressing and microwave sintering. Microstructures and mechanical properties of the prepared composites were systematically characterized and analyzed. The results show that the density and mechanical properties of the composites increase with the increase of Zr content, and the 50Mo30Cu20Zr composite achieves the highest relative density of 97.6%, hardness of 314.4 HV and compressive strength of 805.9 MPa. The increase of Zr content reduces the sintering activation energy and leads to the improvement of density. Simultaneously, the element Zr can form solid solutions and in-situ synthesis intermetallic compounds with Cu matrix, which leads to solid solubility strengthening and dispersion strengthening. Moreover, the interface between Mo and Cu phase is found to have been reinforced by the in-situ intermetallic compound particles embedded in the interface. This work provides an important reference for research of densification and mechanical property of Mo–Cu composites.