Mechanical and thermal properties of nanocarbon-reinforced aluminum matrix composites at elevated temperatures

This study evaluated the mechanical and thermal properties of aluminum alloy 2024 (Al2024) matrix composites reinforced with multi-walled carbon nanotube (MWCNT) or few-layered graphene (FLG) in the temperature range of 250-430 degrees C. The Al2024/MWCNT and Al2024/FLG composites were fabricated using powder metallurgy, and the associated microstructures were observed. At 350 degrees C, both composites maintain high yield stress about 110 MPa, since uniform dispersion of the nano-scale reinforcements has a strong interface, hinders the dislocation movement and eutectic phase coarsening and severe softening of the matrix. The composites also show a low thermal expansion coefficient of similar to 18 x 10(-6)/K. The results are respectively over similar to 2.5 times higher strength and similar to 20% lower CTE than those of commercial Al alloy used as piston material (AlSi12CuMgNi). (C) 2016 Elsevier Ltd. All rights reserved.