Abstract:
In the present study, Al-Mg binary eutectic alloy nanoparticles were synthesized through
the electrical wire explosion technique (EWET) in an inert ambience. High-speed imaging
was carried out to visualize sublimation process of alloy wire and subsequent formation of
nanoparticle through the condensation process. The fundamental gas-phase kinetics is
investigated by the embedded atom method (EAM) and reactive hard-sphere model to
elucidate the mechanisms governing the formation of finer particles of eutectic AlMg alloy.
The condensed phase transformations are analysed through size-dependent thermodynamics
and growth kinetics modelling, which has shown that the adsorption controlled growth is
responsible for the generation of polydispersed particles. The formation of Al20Mg23
nanoparticles and its morphological features were characterised through XRD and SEM/EDS
analysis. High-resolution transmission electron microscopy (HRTEM) along with the selected
area electron diffraction (SAED) confirmed the spherical morphology, crystallinity,
lognormal particle size distribution and the multiphase microstructure of the eutectic AlMg
nanoparticles. The formation of multiphase alloy nanoparticles is attributed to the
insignificant difference in melting temperatures of Al and Mg and phase boundary
modifications due to size-effect. Scanning transmission electron microscopy (STEM)
revealed the spatial distribution of Al and Mg within the alloy nanoparticle. Differential
scanning calorimetry (DSC) confirmed the reduction in melting temperature and fusion
enthalpy of eutectic Al-Mg alloy nanoparticles. It is proposed as a potential substitute for Al
nanoparticles to reduce the ignition temperature, agglomeration and two-phase flow losses for
realising improved combustion performance in solid rocket propellants.
