Atomic composition/configuration dependent bulk moduli of Al–C composites

Embedding carbon in metals has long been known to enhance the mechanical properties of metal carbon composites. We report the possibility of growing Al–C composites by the hot isostatic pressing method, with carbon embedded into an Al lattice in graphitic form without the formation of Al4C3. Raman spectroscopy confirms the formation of sp2-hybridized carbon clusters in the aluminum lattice. The bulk moduli of the samples were measured to be between 60 and 100 GPa. From the results of first principles density functional theory calculations, we show that the formation of sp2-hybridized carbon clusters is more stable than having isolated C scatterers in aluminum. Our results show that the extended network of C clusters shows a higher bulk modulus while isolated scattering centers could lower the bulk modulus. We explain this behavior with the analysis of total charge distribution. Localization of charge density decreases materials’ ability to respond to external stress, thus showing a reduced bulk modulus. Some defect configuration may reduce the symmetry while others keep the symmetry of the host configuration even for the same chemical composition of Al–C composites. This work was partially supported by an NSF grant (Award No. 2138459) and the NSF DMR and DoD Assure REU Program (Award No. 1757954). The authors would like to thank Southern Illinois University for providing the computer facilities.

Creator

• Jayasekera, T.
• Nilufar, S.
• Karunanithy, R.
• Sivakumar, P.
• Rativa-Parada, W.
• Sirikumara, Hansika

Publisher

• AIP Publishing LLC

Language

• English

Identifier

• DOI: https://doi.org/10.1063/5.0117900

Keyword

• Al–C composites
• metal carbon composites
• total charge distribution
• first principles density functional theory calculations

Date created

• 2022

Related URL

• Available from the publisher:  https://aip.scitation.org/doi/abs/10.1063/5.0117900
• DOI:  https://doi.org/10.1063/5.0117900

Resource type

• Article

Source

• AIP Advances (Vol. 12, No.115008)

Rights statement

• http://rightsstatements.org/vocab/InC/1.0/