Thermal expansion of the AlMg10 matrix composites with SiC and graphite particles
Zbigniew Konopka, Małgorzata Cisowska, Agnieszka Rachwalik Politechnika Częstochowska, Katedra Odlewnictwa, al. Armii Krajowej 19, 42-200 Częstochowa
Annals 2 No. 3, 2002 pages 113-116
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abstract The thermal expansion investigations of the AlMg10 matrix composite with SiC and graphite particles were presented. Composite suspension was prepared by stirring method where the propeller stirrer was used and temperature of liquid metal, time of mixing and mixer velocity were fixed during this process. The cylindrical samples of composites and AlMg10 were prepared by suction of melt into 3 mm diameter quartz pipe. These composite samples were used in thermal expansion investigations. Expansion of examined materials as a temperature funcion was measured by using optical dilatometer LS-4. Different composites containing 10, 20 and 30 volume percent of solid particles were examined where voluminal ratio SiC/graphite was 8/2, 15/5 and 20/10. Changes of sample linear dimensions during heating and cooling for composites and AlMg10 comperative were registrated and presented in this paper (Figs 1-4). The coefficient of linear thermal expansion was calculated and diagram of this coefficient as a temperature funcion was presented in Figure 6. Example of composite structure showing uniform distribution of SiC and graphite particles was presented in Figure 5. On the ground of obtained results we can conclude that coefficient of linear thermal expansion for composites was lower in comparison with AlMg10 alloy. After heating-cooling cycle the final contraction of samples was observed. The contraction of composite samples was smaller than for AlMg10 alloy composite matrix. This result shows that dimensional stabilization of composites was improved because of SiC and graphite particles.