Microstructure, microhardness and thermal expansion of CNT/Al composites prepared by flake powder metallurgy

Pham Van Trinh (1, 2) , Nguyen Van Luan (1) , Doan Dinh Phuong (1) , Phan Ngoc Minh (1) , Alicia Weibel (2) , David Mesguich (2) , Christophe Laurent (2)

1 VAST - Vietnam Academy of Science and Technology
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

Carbon nanotube/aluminum (CNT/Al) composites are prepared by a combination of flake powder metallurgy and hot-isostatic-pressing. The specimens are investigated by several techniques including Raman spectroscopy, optical microscopy, scanning- and transmission electron microscopy. The composites show a layered-microstructure with a stacking of CNT/Al flakes with a CNT-rich layer between two flakes. The individual Al grains forming the flakes are about 500 nm in size. The CNTs are well dispersed within a flake and they bridge the micro-cracks. The results reveal that the coefficient of thermal expansion (CTE) decreases markedly upon the increase in carbon content, reaching 15.4 x 10-6 K-1 for the specimen with a carbon content of 2.0 wt% (2.9 vol%), i.e. a 30% decrease compared to the CTE of pure Al. This could arise from the layered-microstructure resulting from the utilization of Al flakes as opposed to rounded particles.

Mots clés: Powder processing; Thermal properties; Metal matrix composite; Carbon nanotubes

Domaines: Matériaux

Pham Van Trinh, Nguyen Van Luan, Doan Dinh Phuong, Phan Ngoc Minh, Alicia Weibel, et al.. Microstructure, microhardness and thermal expansion of CNT/Al composites prepared by flake powder metallurgy. Composites Part A: Applied Science and Manufacturing, 2018, 105, pp.126-137. ⟨10.1016/j.compositesa.2017.11.022⟩. ⟨hal-01728899⟩