High thermal conductivity and strong interface bonding of a hot-forged Cu/Ti-coated-diamond composite

Abstract

Cu/55 vol%diamond (Ti) composites are prepared by hot forging of cold-pressed powder preforms, consisted of pure Cu powders and 50 nm-thick Ti-coated diamond particles, at 800 °C (800-Cu/55Dia) and 1050 °C (1050-Cu/55Dia), respectively. It finds that the TiC coverage of diamond surface is 96% in 800-Cu/55Dia and 70% in 1050-Cu/55Dia. Nano-spherical TiC particles are homogeneously dispersed on diamond surface to form a rough surface for 800-Cu/55Dia. This leads to a strong interface bonding is formed in 800-Cu/55Dia, having a flexural strength of 418 MPa. Sever interfacial layer spallation, smooth and flat surface of interfacial layer make 1050-Cu/55Dia have a relatively low interface bonding. The high coverage of diamond by interfacial layer, formation of dispersed nano-spherical TiC particles, and strong interface bonding enables the thermal conductivity (TC) of 800-Cu/55Dia is as high as 550 W/mK (99% of the theoretical value), and a CTE of 7 × 10−6/K at 313 K. The fabricated copper/diamond composite has better mechanical and thermophysical properties than the most reported copper/diamond (the diamond particle size is < 100 μm) composites, demonstrating that powder hot-forging technique we developed is a cost-effective process and feasible to produce a copper/diamond composite with high mechanical and thermophysical performance for high-power thermal management applications.