Effects of Cu content on microstructures and compressive mechanical properties of CNTs/Al-Cu composites
(1. Institute of Advanced Wear & Corrosion Resistant and Functional Materials, Jinan University, Guangzhou 510632, China;
2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
4. School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China;
5. Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong 999077, China)
2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
4. School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China;
5. Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong 999077, China)
Abstract: The carbon nanotubes (CNTs) reinforced Al-Cu matrix composites were prepared by hot pressing sintering and hot rolling, and the effects of Cu content on the interfacial reaction between Al and CNTs, the precipitation behavior of Cu-containing precipitates, and the resultant mechanical properties of the composites were systematically investigated. The results showed that the increase of Cu content can not only increase the number and size of Cu-containing precipitate generated during the composite fabrication processes, but also promote the interfacial reaction between CNTs and Al matrix, leading to the intensified conversion of CNTs into Al4C3. As a result, the composite containing 1 wt.% Cu possesses the highest strength, elastic modulus and hardness among all composites, due to the maintenance of the original structure of CNTs. Moreover, the increase of Cu content can change the dominant strengthening mechanisms for the enhanced strength of the fabricated composites.
Key words: Al matrix composites; Al-Cu precipitates; carbon nanotubes; interfacial reaction; strengthening mechanism