Microstructure and thermal properties of copper matrix composites reinforced with titanium-coated graphite fibers
- PDF / 532,404 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 89 Downloads / 245 Views
Rare Met. (2013) 32(1):75–80 DOI 10.1007/s12598-013-0018-0
www.editorialmanager.com/rmet
Microstructure and thermal properties of copper matrix composites reinforced with titanium-coated graphite fibers Hao-Ming Zhang, Xin-Bo He*, Xuan-Hui Qu, Qian Liu, Xiao-Yu Shen
Received: 22 February 2012 / Revised: 11 June 2012 / Accepted: 15 June 2012 / Published online: 21 February 2013 Ó The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg 2013
Abstract Milled form of mesophase pitch-based graphite fibers were coated with a titanium layer using chemical vapor deposition technique and Ti-coated graphite fiber/Cu composites were fabricated by hot-pressing sintering. The composites were characterized with X-ray diffraction, scanning/transmission electron microscopies, and by measuring thermal properties, including thermal conductivity and coefficient of thermal expansion (CTE). The results show that the milled fibers are preferentially oriented in a plane perpendicular to the pressing direction, leading to anisotropic thermal properties of the composites. The Ti coating reacted with graphite fiber and formed a continuous and uniform TiC layer. This carbide layer establishes a good metallurgical interfacial bonding in the composites, which can improve the thermal properties effectively. When the fiber content ranges from 35 vol% to 50 vol%, the in-plane thermal conductivities of the composites increase from 383 to 407 W(mK)-1, and the in-plane CTEs decrease from 9.5 9 10-6 to 6.3 9 10-6 K-1. Keywords Metal matrix composites; Titanium coating; Microstructure; Thermal conductivity; Coefficient of thermal expansion
H.-M. Zhang, X.-B. He*, X.-H. Qu, Q. Liu, X.-Y. Shen School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China e-mail: [email protected] X.-H. Qu State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
1 Introduction Improved performance and smaller scale are two features for new applications in the electronics industry. Both of these targets result in increased heat flux densities within electronic devices, and thereby, the effective thermal management becomes a very important issue for packaging of high-performance semiconductors [1]. The electronic packaging materials should have a high thermal conductivity to effectively dissipate heat and a low coefficient of thermal expansion (CTE) to minimize thermal stresses [2]. This is of vital importance to enhance the performance, life cycle, and the reliability of electronic devices. Traditional packaging materials like Kovar, Cu/W, Cu/Mo or SiC/Al, which suffer from certain limitations of their relatively low thermal conductivity (no more than 250 W(mK)-1), are no longer sufficient to fulfill the requirements of heat removal of the most recent power electronic devices [3, 4]. Recently developed diamond/metal composites family, despite featuring very high thermal conductivity [5, 6], has so far been limited to niche markets
Data Loading...
