Thermostructural properties of the Al + 1.5% MWCNT nanocomposite

The work was aimed to study the influence of multi-walled carbon nanotubes (MWCNT) on the thermostructural properties of aluminum matrix in a wide temperature range from 30 to 600 °C. To achieve this aim, a nanomaterial with a composition of Al + 1.5% MWCNT was elaborated by sintering and rolling from aluminum and MWCNT powders. This material has to combine the ductility and lightness of aluminum with the toughness and thermal properties of MWCNT, and it can replace classical metal materials. The mechanical and structural properties of Al + 1.5% MWCNT material were studied using different techniques: differential scanning calorimetry, X-ray diffraction, thermogravimetry, Raman spectroscopy, and dilatometry. The reaction between an Al matrix and nanotubes leads to the formation of the carbides and some carbon dissolution in the matrix’s crystal network. These reactions also lead to a refinement of the matrix grain and a more homogeneous distribution of the residual MWCNT. These phenomena significantly influence the structure of the matrix as well as the mass and dilatometric stability of the material. Reduction of the dilatometric coefficients of the composite material was observed in the entire temperature range of 30–600 °C, especially a significant reduction was measured for temperatures higher than 200 °C. The results obtained by differential calorimetry showed a noticeable decrease in the calorific capacity of the nanocomposite compared to that of the pure material, especially for temperatures higher than 200 °C. The essential role of anisotropy in determining the thermal expansion characteristics of the nanocomposite was revealed.