Spark Plasma Sintering of Ultrafine YSZ Reinforced Cu Matrix Functionally Graded Composite

Abstract

Copper matrix composites have received more attentions as possible candidate for thermal and electrical conductive materials to be used in electrical contact applications. In this study, five-layered Cu/YSZ (yttria-stabilized zirconia) functionally graded material (FGM) and copper matrix composite specimens containing 3 and 5 vol% YSZ particles plus pure Cu specimen were synthesized using powder metallurgy (PM) route and spark plasma sintering (SPS) consolidation process. The microstructural and some physical, mechanical features of all specimens were characterized. Microscopic examinations showed that ultrafine YSZ particles were distributed in the copper matrix almost homogeneously. An appropriate interface was observed at each layer of FGM. The density measurement indicated that the graded structure of the composite could be well densified after the SPS process. The microhardness values of various layers of Cu/ YSZ FGM specimen were gradually altered from 56.3 (pure copper side) to 75.2 HV (Cu-5 vol% YSZ side). The increase of YSZ content resulted in a decrease in electrical conductivity. Additionally, thermal conductivity of Cu/YSZ FGM specimen [308.0 W/(m K)] was determined to be higher than that of the Cu-5 vol% YSZ composite specimen [260.7 W/ (m K)]. Accordingly, it can be concluded that the Cu/YSZ FGM can be a good candidate for the electrical applications, like sliding electrical contacts, where different material characteristics in the same component are required.

Review on developments of bulk functionally graded composite materials

“…The fabricated FGCM was free from defects such as cracks, voids and delaminations. Ultrafine YSZ reinforced Cu matrix FGCMs were fabricated by Mirazimi et al [174]. The FGCM had five layers, and the maximum YSZ content was 5 vol.-%.…”

“…Data points for the thermal conductivity of pure W were collected from [248]. SiO 2 -Mo and Cu-YSZ FGCMs were studied by Honma and Tatami [173] and Mirazimi et al [174], respectively. Both studies reported an increase in the electrical resistivity with increasing ceramic content.…”

“…An intact copper network has been deemed to be essential for a high thermal conductivity in these FGCMs. In another work, the thermal conductivity of YSZ reinforced Cu FGCM was studied by Mirazimi et al [174]. Although the thermal conductivity decreased with increasing YSZ content, the overall conductivity of the Cu-YSZ FGCM was higher than monolithic composites, making them attractive materials for thermal management applications.

Figure 46. Thermal conductivity of different Fe-W composites as a function of temperature [190] (cited image has been reproduced with due permission from the publisher).

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Synthesis and Evaluation of Strengthened Copper with 3 wt. % TiC and/ or Al2O3 Prepared By SPS Technique

“…The addition of ceramics such as titanium carbide or alumina to copper increases its electrical resistivity and decreases the electrical conductivity [1]. The increase of lattice defects reduces the electron's mean free path and affects the electrical conductivity values [48]. This also can be explained by the zero electrical conductivity values of both TiC and Al2O3 which decreases the overall conductivity of the prepared composites [1].…”

Production and properties of Cu-ZrO2 nanocomposites

“…Among these, however, fine stabilized ZrO 2 ceramic particles could be a proper reinforcing material due to their high strength and stiffness, high melting temperature, and relatively good electrical property. 18 Although noticeable studies have been performed on the fabrication and characterization of ZrO 2 matrix composites reinforced with other ceramic materials, [19][20][21] the addition of ultrafine grained ZrO 2 particles to copper matrix and its subsequent effect on the microstructure, physical and mechanical properties as well as tribological behavior of copper matrix have been notified limitedly.…”