A Novel Cu–GNPs Nanocomposite with Improved Thermal and Mechanical Properties Abdollah Saboori 1 • Matteo Pavese 1 • Claudio Badini 1 • Paolo Fino 1 Received: 26 May 2017 / Revised: 15 July 2017 / Published online: 28 August 2017 Ó The Chinese Society for Metals and Springer-Verlag GmbH Germany 2017 Abstract Classical powder metallurgy followed by either hot isostatic pressing (HIPing) or repressing–annealing process was used to produce Cu–graphene nanoplatelets (GNPs) nanocomposites in this work. A wet mixing method was used to disperse the graphene within the matrix. The results show that a uniform dispersion of GNPs at low graphene contents could be achieved, whereas agglomeration of graphene was revealed at higher graphene contents. Density evaluations showed that the relative density of pure copper and copper composites increased by using the post-processing techniques. However, it should be noticed that the efficiency of HIPing was remarkably higher than repressing–annealing process, and through the HIPing, fully dense samples were achieved. The Vickers hardness results showed that the reconsolidation steps can improve the mechanical strength of the specimens up to 50% owing to the progressive porosity elimination after reconsolidation. The thermal conductivity results of pure copper and composites at high temperatures showed that the post- processing techniques could enhance the conductivity of materials significantly. KEY WORDS: Copper; Graphene nanoplatelets (GNPs); Powder metallurgy; Hot isostatic pressing; Thermal conductivity 1 Introduction In the electronic packaging industries, thermal considera- tions in the material design of new electronic devices are a very important factor [1–3]. It was indicated that the materials with high thermal conductivity and low coeffi- cient of thermal expansion (CTE) are required for the applications [2, 3]. Copper is one of the most important candidates which can be used in the electronic packaging industries because of its high thermal and electrical con- ductivity and cost [4, 5]. To broaden the application of copper and its alloys, it is necessary to develop new kinds of composite materials with improved characteristics [6–8]. In this regard, uniform dispersion of reinforcement and strong interfacial bonding between the reinforcement and matrix are essential to exploit the full potential of the composite. GNPs have been attracted considerable atten- tions as reinforcement due to their unique mechanical, thermal and electrical characteristics [9–12]. Since casting is not an appropriate fabrication technique for this kind of the composites, due to the poor wettability between the molten copper and GNPs, powder metallurgy techniques are developed to produce the copper based composites [13–16]. The aim of this study was to investigate the effect of GNPs on thermo-physical and mechanical characteristics of copper composites. Moreover, the effects of reconsoli- dation step, for the first time, were evaluated in order to develop new Cu/GNPs composites with superior mechan- ical and thermal properties. Available online at http://link.springer.com/journal/40195 & Abdollah Saboori abdollah.saboori@polito.it 1 Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy 123 Acta Metall. Sin. (Engl. Lett.), 2018, 31, 148–152 https://doi.org/10.1007/s40195-017-0643-y