Ultrasonic vibration enabled cold manufacturing of high thermal conductive Cu/Diamond composites

The development of electronic components has put forward higher requirements for heat dissipation materials, manifested in the pursuit of higher thermal conductivity and lower thermal expansion. Cu/Diamond composite, combining excellent thermal conductive performance and process ability. However, it is limited by strict preparation conditions, such as high temperature and pressure, or complex intermediate medium coating. This work proposes a one-step and heat-source-free cold manufacturing method to fabricate Cu/Diamond composite under room temperature and a low pressure of ~16 MPa within seconds via ultrasonic vibration. The applied pressure decreased by 200 to 500 times, and the required temperature was only 20% of the commonly used high-temperature and high-pressure sintering (HTHP) method. Direct metallurgical bonding between the interfaces of Cu particles and solid embedding of diamond in the Cu matrix was achieved, leading to the high yield strength of the composite (150 MPa). Following the proposed strategy, a maximum diamond proportion of about 60% in the composite can be prepared, which shows high thermal conductivity over 1043 W/(m K) and a minor thermal expansion coefficient less than 10 (10−6 K−1). In addition, composites of different complex shapes were readily fabricated through the flexible method. The heat dissipation application test reveals its better thermal management performance than commercial Al2O3 and AlN. Our results demonstrate that ultrasonic vibration assisted cold manufacturing is a facile and efficient way to prepare Cu/Diamond composite with excellent properties. Loose preparation conditions empower it with industrial production potential.