방전플라즈마소결법을 통해 제조된 Al-Cu 복합재료의 소결거동분석

Abstract

The aluminum(Al)-copper(Cu) composites such as Al-20, 50 and 80 vol.%Cu were fabricated by spark plasma sintering(SPS) process. We systematically investigated the effect of intermetallic compounds(ICs) formed during sintering on the mechanical properties and thermal conductivity of the composites. The Al-Cu composite powder prepared by mechanical ball milling process with 300 rpm rotation speed for 24 hours using heptane 20 ml as process control agent (PCA). Field emission-electron probe micro Anlayzer (FE-EPMA) showed that Cu particles were encapsulated by the deformed Al. It was observed that the IC between Al and Cu was formed during SPS and was identified as Cu9Al4 or CuAl2 by the X-ray diffraction (XRD) patterns. It showed that the formation and growth of ICs were controlled by the sintering conditions such as temperature, pressure and holding time. Mechanical properties of Al-Cu composites were evaluated by Vickers hardness test and the hardness value measured was compared with the theoretical values calculated by the rule of mixture. The thermal conductivity of the composites was measured by Laser Flash Thermal Conductivity Measuring System (LFA) at room temperature. The composite fabricated at 380 ℃ with 250 MPa pressure and 5 min holding time showed the highest thermal conductivity (201 W·m-1·K-1). In conclusion, the Al-Cu composites fabricated by SPS showed good mechanical and thermal properties. It also showed that the mechanical and thermal properties of the composite can be controlled by the amount of ICs which depending on the sintering conditions. Experimental results obtained suggest that Al-Cu composites have the possibility to be applied to thermal management system.