SUMMARY
UCLA researchers in the Department of Mechanical and Aerospace Engineering have developed a cost-effective method to produce copper-based nanocomposites with excellent mechanical, electrical and thermal properties.
BACKGROUND
High performance copper-based materials are needed for a wide range of applications, spanning industries as diverse as aerospace, energy, transportation, and electronics. The current methods of modifying pure copper to achieve these high-performance characteristics all have significant drawbacks. Alloying cannot achieve tensile strengths above 600 MPa with good ductility and reasonable thermal and electrical conductivity, and alloys soften at high temperature. Severe plastic deformation can increase the strength of copper, but significantly decreases its ductility and thermal stanility. Other approaches present challenges in scaling to industrial production levels. Copper-based nanocomposites show promise, but uniform dispersion of nanoparticles within the metal matrix is required and has proven difficult to achieve.
INNOVATION
UCLA researchers have developed a scalable method to produce copper-based nanocomposites with desirable mechanical, electrical and thermal properties. The process uses a salt-assisted method to uniformly distribute the nanoparticles in copper and copper alloys, and can be readily applied to industry-scale production. By varying the amount of nanoparticles used, the functional properties of the resultant material can be tuned to desired specifications. Ingots of cast copper nanocomposites made with this method can be processed with standard methods such as hot rolling, cold rolling, and extrusion. Lab tests produced the following results: an average yield strength of 1020.7±244.3 MPa, with a uniform plasticity of more than 8%; microhardness exceeding 478 HV; and a Young’s Modulus of 254.4±11.2 GPa (compared to ~115 GPa for copper and copper alloys). By varying the composition of nanoparticles, the resultant material can be tuned for a range of thermal and electrical conductivities. For example, Cu/12.5 vol.% WC nanocomposite offers a thermal conductivity of 304.1±2.3 W/(mK) and similarly impressive conductivities were noted for copper alloys produced with this method.
POTENTIAL APPLICATIONS
- Terminals and connectors for electrical, electronic and automotive applications
- Rotors for electric motors
- High-speed railway contract wires
- Electric resistance welding electrodes
- Integrated circuit leadframes
- Heavy electrical switchgear
ADVANTAGES
- Scalable, cost-effective manufacturing process
- Tunable, high-performance mechanical properties
- Tunable, high thermal and electrical conductivity
RELATED MATERIALS
STATE OF DEVELOPMENT
Copper-based nanocomposites have been successfully synthesized with varying amounts of other elements demonstrating tunable, high-performance properties.