Process optimization, microstructures and mechanical/thermal properties of Cu/Invar bi-metal matrix composites fabricated by spark plasma sintering
(1. School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China;
2. Electric Power Research Institute, State Grid, Anhui Electric Power Co., Ltd., Hefei 230601, China;
3. The 43 Research Institute of China Electronics Technology Group Corporation, Hefei 230088, China;
4. Anhui Province Key Laboratory of Microsystem, Hefei 230088, China;
5. Hefei Shengda Electronic Technology Industry Co., Ltd., Hefei 230088, China;
6. Engineering Research Center of High-performance Copper Alloy Materials and Processing, Ministry of Education, Hefei 230009, China)
2. Electric Power Research Institute, State Grid, Anhui Electric Power Co., Ltd., Hefei 230601, China;
3. The 43 Research Institute of China Electronics Technology Group Corporation, Hefei 230088, China;
4. Anhui Province Key Laboratory of Microsystem, Hefei 230088, China;
5. Hefei Shengda Electronic Technology Industry Co., Ltd., Hefei 230088, China;
6. Engineering Research Center of High-performance Copper Alloy Materials and Processing, Ministry of Education, Hefei 230009, China)
Abstract: An orthogonal experiment scheme was designed to investigate the effects of the Cu content, compaction pressure, and sintering temperature on the microstructures and mechanical and thermal properties of (30-50)wt.%Cu/ Invar bi-metal matrix composites fabricated via spark plasma sintering (SPS). The results indicated that as the Cu content increased from 30 to 50 wt.%, a continuous Cu network gradually appeared, and the density, thermal conductivity (TC) and coefficient of thermal expansion of the composites noticeably increased, but the tensile strength decreased. The increase in the sintering temperature promoted the Cu/Invar interface diffusion, leading to a reduction in the TC but an enhancement in the tensile strength of the composites. The compaction pressure comprehensively affected the thermal properties of the composites. The 50wt.%Cu/Invar composite sintered at 700 °C and 60 MPa had the highest TC (90.7 W/(m·K)), which was significantly higher than the TCs obtained for most of the previously reported Cu/Invar composites.
Key words: spark plasma sintering (SPS); Cu/Invar bi-metal composite; microstructure; interface diffusion; mechanical property; thermal property