Estimation of Effective Thermal Conductivity of Copper-Plated Carbon Fibers Reinforced Iron-Based Composites by 2D Image Analysis

Abstract

Dies with high thermal conductivity (TC) can not only speed up heat transfer but also improve the production efficiency of parts and extend the life of the dies. Taking advantage of the high axial TC of carbon fibers (Cf), thermal channels are established in the composite. To protect Cf from being destroyed, Cf was electroless plated with Cu to form copper-plated Cf (Cf-Cu). Pores impede heat conduction, and the TC of the matrix is corrected by Bruggeman’s equation. Cf-Cu has high anisotropic, and its orientation can significantly affect the TC of iron-based composites. The mathematical equation between the orientation of Cf-Cu in the 3D model, the orientation of Cf-Cu on 2D cross-section, and the aspect ratio of an ellipse were obtained by Cf-Cu intersects with cross-section was determined by establishing a model of the orientation of Cf-Cu in 3D space. The simulated TC of the composite was calculated by 2D image analysis (finite element method). The effect of the orientation of Cf-Cu on the TC of composites with different Cf-Cu contents was investigated. When the volume fraction of Cf-Cu was 20%, the measured and simulated TC reached the maximum of 68.89 W m−1 K−1 and 71.02 W m−1 K−1, respectively. Before rolling, there is a significant difference between the simulated and measured TC. After rolling on the side surface of the rolling plane of the composite, both the simulated and measured TC on the rolling plane and its side surface show the same trend with the increasing of Cf-Cu content.