Nanocrystalline carbon nanotube (CNT)-reinforced Cu composite (grain size <25 nm) with high strength and good ductility was developed. Pillar testing reveals that its strength and plastic strain could be as large as 1700 MPa and 29%, respectively. Compared with its counterpart made under the same condition, an addition of 1 wt % CNTs leads to a dramatic increase in strength, stiffness and toughness without a sacrifice in ductility. Microstructural analysis discloses that in the Cu matrix, CNTs could be distributed either at grain boundaries or inside grains and could inhibit dislocation nucleation and motion, resulting in an increase in the strength.
Bibliographical noteFunding Information:
This study was supported by the DOE, Office of Science, Office of Basic Energy Sciences. ZH appreciates the support of Kyushu University P&P program. The authors gratefully acknowledge John Kennison for his assistance in performing powder compaction.