Microstructure and properties characterization of tungsten–copper composite materials doped with graphene

Abstract

Graphene is considered as an excellent reinforcement in composite materials because of its unique physical and mechanical properties. In this study, graphene was successfully prepared at the reducing temperature of ambient temperature by oxidation reduction process using a green reducing agent and an attempt was made to fabricate graphene/W70Cu30 composites by mechanical alloy and pressureless infiltration sintering technology. Effect of graphene addition on W70Cu30 powders and W70Cu30 composites were characterized by using transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, Optical microscopy (OM) and HB-3000 hardness tester. The results show that the graphene could remain after ball milling and sintering process. But, the carbides (like WC and W2C) were also formed in bulk composites, which revealed that some of graphene would react with W during the sintering process, but the graphene coated with Cu phase in W70Cu30 alloy still keep intrinsic structures. And W grain size is efficiently refined with addition of graphene. The relative density of graphene/W70Cu30 composites enhance with the content of graphene increasing. When the graphene content is 1.0 wt%, the relative density of composites reach up to 98.4%, which is considered that graphene could improve the wettability of W and Cu. The incorporation of graphene into W7Cu30 alloy gradually increases the hardness of composites, which is enhanced about 21% compared with the pure W70Cu30 when the graphene content is 1.0 wt%. The electrical conductivity of composites increase gradually firstly and decrease sharply with the increase of graphene content. When the 0.5 wt% graphene was added to the W70Cu30 alloys, the maximum conductivity reaches ∼46% IACS.