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The role of the matrix in SiC reinforced composites

Madej Marcin, Leszczyńska-Madej Beata, Wąsik Anna, Kopeć-Surzyn Anna

Composites Theory and Practice

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2023

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R. 23, nr 1

30--36

EN

This article presents a comparison of the properties of composites based on aluminum or aluminum alloy (Al4Cu) rein- forced with silicon carbide SiCp. The main objective was to analyze the possibility of producing an Al + Cu alloy matrix by basic powder metallurgy methods and its influence on the final properties of the composite. The composites were produced by pressing and sintering, basic powder metallurgy techniques, in order to reduce the manufacturing costs. Sintering was carried out in nitrogen due to the favorable effect of this atmosphere on the sintering of aluminum-based materials. Silicon carbide SiC was used as the reinforcing phase. The study clearly showed that the use of a matrix made of a mixture of Al and Cu powders results in an almost twofold increase in hardness (from 32 to about 60 HB) and a more than twofold increase in flexural strength (from about 200 to more than 450 MPa). Observations of the microstructure confirmed the diffusion of copper into the aluminum and the facets of the Al2Cu phase.

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Effect of production process parameters on densification, microstructure and selected properties of spark plasma sintered Al4Cu-xSiC composites

Madej Marcin, Leszczyńska-Madej Beata, Wąsik Anna, Kopeć-Surzyn Anna, Korban Patryk, Garbiec Dariusz

Composites Theory and Practice

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2023

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R. 23, nr 3

173--180

EN

The paper presents the results of a study on the microstructure and hardness measurements of Al4Cu-xSiC (x = 5, 10, 20 and 30 wt.%) composites produced by spark plasma sintering (SPS). The sintering process was carried out in an HP D 25/3 plasma sintering furnace in a vacuum atmosphere, with sintering temperatures of 580 and 600°C and a densification pressure of 50 MPa. The heating rate was 100°C/min and the isothermal holding time at the sintering temperature was 2.5 min. As a reference material, the AlCu matrix was sintered under the same conditions. As a result, composites with a near-full density of 96.5-99.5% were obtained. Microstructure studies were performed employing the techniques of light microscopy, scanning, and transmission electron microscopy, along with analysis of the chemical composition in microareas. The test results did not reveal remarkable differences in the microstructure of the investigated composites sintered at 580 and 600°C. The sinters have a fine-grained microstructure with a strengthening phase located at the grain boundaries; locally, pores are visible. Increasing the SiC content in the composites promotes the formation of agglomerates of these particles. It was proven that a higher sintering temperature has a positive effect on the hardness of the studied composites.

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Spark plasma sintering of Al-SiC composites with high SiC content: study of microstructure and tribological properties

Leszczyńska-Madej Beata, Madej Marcin, Wąsik Anna, Garbiec Dariusz

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 4

art. e229, 1--13

EN

The article presents the results of the microstructure and tribological properties of Al-xSiC composites (x =70 and 90 wt% SiC) produced in spark plasma sintering (SPS). Due to their attractive thermal, physical, and mechanical properties, aluminum matrix composites with high-volume fractions of silicon carbide (> 50%) have become a major area of interest as a potential material for multifunctional electronic packaging and cryogenic applications. The SPS process was carried out in a vacuum atmosphere under various conditions. Composites with a density close to theoretical (96-98%) were obtained. X-ray diffraction and scanning electron microscopy with EDS analysis were used to characterize the microstructure. Mechanical properties were determined by hardness measurements and a three-point bending test. The tribological properties of the composites were determined utilizing a block-on-ring tribotester. As a criterion for wear resistance, weight loss measured under specific friction conditions, that is, depending on the type of material and the applied load, was adopted. The researched materials were characterized by an even distribution of the carbide phase in the matrix. Composites with the highest SiC phase content (90 wt%) had higher hardness (2537 HV1) and flexural strength (242} 15 MPa) with worse wear resistance at the same time. The weight loss of this composite was 0.43 and 0.76% for friction under loads of 100 and 200 N, respectively, and was 360 and 270% higher than that determined for the composites with the lower content of the SiC phase (70 wt%). The wear rate was three times higher for the Al-90wt%SiC composites.