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- MakaleAçık Erişim2026Scopus SJRQ2Effect of Zinc Content on the Mechanical, Corrosion, Tribological and Electrical Properties of Spark Plasma-Sintered Copper/Graphene Composites
Özkaya, Serdar; Adabaş, Yaren; Çelebi, Müslim; Karabacak, Abdullah Hasan; Çelik, Ertuğrul
Copper-based hybrid metal matrix composites reinforced with graphene and zinc were developed to achieve a balanced combination of mechanical strength, corrosion resistance, wear performance, and electrical conductivity. In this study, Cu matrix composites containing a constant graphene content of 1 wt.% and varying Zn contents (0, 5, 10, and 15 wt.%) were fabricated through mechanical alloying followed by Spark Plasma Sintering (SPS). The effects of zinc content on microstructure, densification, hardness, corrosion behavior, tribological performance, and electrical conductivity were systematically investigated. Microstructural analyses revealed that the combined use of graphene and Zn significantly influenced grain refinement, interfacial stability, and densification behavior. The composite containing 10 wt.% Zn exhibited the highest relative density (~90.5%) and maximum hardness (62 HB), indicating an optimal reinforcement level. Corrosion tests conducted in 3.5 wt.% NaCl solution demonstrated that the 10 wt.% Zn composite showed the most noble corrosion potential and the lowest corrosion current density, which was attributed to reduced porosity and improved microstructural homogeneity. Tribological results confirmed that graphene contributed to a self-lubricating effect, while Zn enhanced load-bearing capacity, leading to improved wear resistance under increasing normal loads. Electrical conductivity measurements showed a gradual decrease with increasing Zn content, mainly due to solid-solution-induced electron scattering in the Cu matrix; however, the fixed graphene addition and effective SPS consolidation helped preserve conductive pathways, allowing all composites to retain acceptable conductivity levels. The results indicate that the hybrid Cu–graphene–Zn composites exhibit a balanced combination of mechanical, corrosion, tribological, and electrical properties, with 10 wt.% Zn emerging as the optimal composition.
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İncele - MakaleAçık Erişim2026Scopus SJRQ1The Role of Graphene on Microstructural, Mechanical, and Tribological Properties of Cu–AlCrFeCuNi Metal Matrix Composites Fabricated via Spark Plasma Sintering
Yanar, Harun; Çelebİ, Müslİm; Sekban, Dursun Murat; Özkaya, Serdar; Karabacak, Abdullah Hasan; Çelİk, Ertuğrul
In this study, Cu-based AlCrFeCuNi high-entropy alloy (HEA) composites reinforced with graphene were fabricated using a mechanical-alloying-assisted spark plasma sintering (SPS) technique. The HEA reinforcement content was kept constant at 20 wt pct for all samples, while the graphene content was varied at 0, 0.5, 1.0, and 2.0 wt pct to investigate its influence on the microstructure, hardness, and tribological performance. The results indicate that both the HEA particles and graphene exhibit an almost homogeneous distribution within the matrix; however, increasing graphene content led to noticeable graphene accumulation along grain boundaries. With higher graphene fractions, the relative density decreased from 97.51 to 94.92 pct, whereas the hardness increased up to the 1.0 wt pct graphene addition, reaching 134.16 HB, followed by a slight decrease to 129.25 HB at 2.0 wt pct. Furthermore, graphene reinforcement significantly improved the tribological behavior of the composites, providing a substantial reduction in wear. The addition of graphene significantly decreased the coefficient of friction from about ~ 0.70 in the Cu–HEA alloy to 0.08 at 2.0 wt pct graphene. Graphene also suppressed the pronounced frictional fluctuations observed in the base alloy, leading to a much more stable sliding behavior. As a result, wear loss was reduced by nearly 99 pct, primarily due to the formation of a continuous lubricating tribofilm on the contact surface.
AtıfScopus3WoS4OpenAlex4İncele - MakaleAçık Erişim2025Scopus SJRQ2Effect of B4C Amount on Microstructural and Mechanical Properties of Cu/h-BN/B4C Metal Matrix Composites Fabricated via Spark Plasma Sintering
Çelebi, Müslim; Karabacak, Abdullah Hasan; Özkaya, Serdar; Çelik, Ertuğrul; Sekban, Dursun Murat; Çanakçı, Aykut; Yanar, Harun
Copper (Cu) is widely used in electrical, electronic, and tribological systems owing to its excellent electrical and thermal conductivity. However, its relatively low hardness and poor wear resistance limit its use in demanding engineering applications. In this study, Cu-based hybrid metal matrix composites (MMCs) reinforced with hexagonal boron nitride (h-BN) and boron carbide (B4C) were fabricated via spark plasma sintering (SPS) to improve their mechanical and tribological performance. The h-BN content was fixed at 1 wt.% to ensure solid lubrication, while the B4C content was varied (0.25, 0.5, 0.75, and 1 wt.%) to examine its influence on the microstructural, mechanical, electrical, and wear properties of the composites. Microstructural analyses confirmed a homogeneous distribution of h-BN and B4C particles in the Cu matrix at low and moderate reinforcement levels, whereas excessive B4C resulted in partial agglomeration and reduced densification. All composites achieved relative densities above 95%, demonstrating the high densification efficiency of the SPS process. Hardness increased markedly with B4C addition due to dispersion strengthening and grain refinement, while electrical conductivity decreased slightly because of the insulating nature of the reinforcements. Tribological tests showed that the composite containing 0.75 wt.% B4C exhibited the best performance, with the lowest wear rate and stable friction behavior. Overall, the results indicate that co-reinforcing Cu with h-BN and B4C through SPS is a promising strategy for developing multifunctional materials suitable for electrical contact and sliding applications.
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