Mechanochemical synthesis mechanism of Ti3AlC2 MAX phase from elemental powders of Ti, Al and C

• Synthesis of Ti3AlC2 MAX phase by mechanochemical synthesis route.
• Mechanically induced self-propagating reaction (MSR) is dominant mechanism.
• Thermodynamic investigations to show feasibility of self-sustain reaction.
• No intermetallic transition phase formed during ball milling.
• Synthesis was completed up to 10 h.

In this study, the synthesis of Ti3AlC2 MAX phase in Ti–Al–C system was investigated by high-energy ball milling. To this aim, mixtures of Ti, Al and C with stoichiometric ratios were milled by a planetary ball mill for different milling times up to 10 h. The structural evaluation of powder particles, after different milling times, was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS) and measurement of vial temperature. Thermodynamic investigations showed that direct reactions among elemental powders of titanium, aluminum, and carbon were strongly exothermic and the product phases were formed in a self-sustaining regime. The experimental result showed that after 10 h milling the elemental powders reacted together through a rapid combustion reaction process resulting in the formation of Ti3AlC2 and TiC. It was proved that mechanically induced self-propagating reaction (MSR) is dominant mechanism.

A simple proposed reaction mechanism shows the formation sequence of Ti3AlC2 from the elemental powders during mechanochemical synthesis.Figure optionsDownload as PowerPoint slide