Synthesis and thermal behavior of Cu/Y2W3O12 composite

Abstract

Cu metal matrix composite with Y2W3O12 as a thermal expansion compensator was fabricated by high energy ball milling followed by compaction and sintering, and its thermal properties were explored for the potential applications as heat sinks in electronic industries, high precision optics, and space structures. The volume fraction of reinforcement was varied from 40% to 70% in order to tailor the composite for the simultaneous accomplishment of low thermal expansion and high thermal conductivity. The synthesis technique was optimized by varying the parameters like milling time from 1 to 20h and sintering temperature from 600 to 1000°C in order to achieve densified composites. The relative density of the composites is found to be around 90% for the 10h milled powders followed by compaction at a pressure of 700MPa and sintering at a temperature of 1000°C. The thermal expansion of the composites exhibits linear behavior in the temperature range 200 to 800°C and the low coefficient of thermal expansion (CTE) is found to be for Cu–70%Y2W3O12 composite whose value, 4.32±0.75×10−6/°C, matches with that of Si substrate. The thermal conductivities are found to increase with a decrease in the volume fraction of the reinforcement and decrease with an increase in the temperature for all the samples. The experimentally determined CTE and thermal conductivity values are found to be comparable to those predicted by the thermal expansion based Kerner and Turner model and the thermal conductivity based Maxwell model, respectively.