The Influence of Aluminum Nitride Nanoparticles on the Structure, Phase Composition, and Properties of TiB/Ti-Based Materials Obtained by SHS Extrusion

Abstract

Compact ceramic long-dimensional materials based on titanium monoboride modified with aluminum nitride dopants (3 and 5 wt %) were obtained via SHS extrusion. Titanium monoboride was produced using azide technology of self-propagating high-temperature synthesis (SHS-Az). Small dopants of nanoscaled aluminum nitride powder exert a strong influence on the phase composition, structure, and physicomechanical properties of samples prepared by SHS extrusion. Scanning electron microscopy data reveal the refinement of the main titanium monoboride phase grains in modified samples. The most pronounced refinement of titanium monoboride grains is observed as the AlN nanopowder content is increased to 5 wt %. The combustion characteristics (temperature and combustion rate) are measured in an installation simulating the real SHS extrusion conditions. It is established that AlN at its content of 3 wt % in the initial charge interacts with the titanium matrix during combustion with the formation of the Ti₂AlN and Ti₄AlN₃ MAX phases. AlN at a concentration of 5 wt % undergoes decomposition during combustion with release of titanium nitrides and pure aluminum, as well as the TiB, TiB₂ and Ti₂AlN phases. Modified compact ceramic materials are shown to exhibit higher microhardness in comparison with samples without using nanomodified AlN dopants.