Interface in carbon nanotube reinforced aluminum silicon composites: Thermodynamic analysis and experimental verification

Interface in carbon nanotubes (CNTs) reinforced aluminium-silicon composites are studied via thermodynamic and kinetic analysis. A pseudo-phase diagram has been generated based on the thermodynamic calculations to predict the type of carbide (Al4C3 or SiC) that would form at the matrix-CNT interface as a function of matrix composition and processing temperature. The pseudo-phase diagram is useful in high temperature processes like thermal spray forming. Critical thickness values for carbide nucleation suggest the formation of Al4C3 with Al-11.6 wt.% Si alloy and SiC with Al-23 wt.% Si alloy. Thermodynamic calculations show that the amount of Al4C3 increases with an increase in the CNT content. The computed results perfectly agree with the results obtained by XRD, SEM of fracture surface and high-resolution transmission electron microscopy (HRTEM) observations on Al-11.6 wt.% Si and Al-23 wt.% Si alloy reinforced with CNT.