The effect of aluminum nitride nanoparticles on the structure, phase composition and properties of materials of the Ti-B-Fe system obtained by SHS-extrusion

Abstract

The SHS-extrusion method, which combines the combustion processes in the mode of self-propagating high-temperature synthesis (SHS) and the subsequent high temperature shear deformation of the combustion products, was used to obtain metal-ceramic composite materials based on titanium boride with an iron matrix modified by additives of nanoaluminum nitride of grade SHS-Az. It was shown that small additions of nanoscale aluminum nitride powder (3 and 5 wt.%) to the initial mixture of the Ti-B-Fe system had a significant effect on the temperature and combustion rate of the system: the combustion rate decreased from 16 to 9 mm / s and the combustion temperature from 1830-1900°C to 1730-1780°C. The results of X-ray phase analysis showed that the modifying AlN nanopowder decomposed during the SHS process and interacted with titanium and iron matrix forming additional phases of TiN and AlFe 3. This is the main cause of the reduction of the temperature and combustion rate during synthesis. A refinement of the grains of titanium diboride in the modified samples from 0.5-2.5 μm to 0.1-1.5 μm was observed using a scanning electron microscope. Microhardness measurements showed that the obtained compact metal-ceramic materials modified with the nanoscale AlN powder had 10 % higher microhardness values compared to samples without additives.

Coatings Prepared by Electro-Spark Alloying with SHS Electrode Materials Based on Ti-B-Fe-AlN

“…Since metal-cutting tools are predominantly made of alloy steel, iron is used as a metal binder. The authors [51] compared the structure and properties of SHS electrode materials based on titanium borides obtained by SHS extrusion, in which iron acted as a metal binder, and the same materials modified with aluminum nitride nanoparticles. For the composition without any modifier, it was found that the SHS electrode materials consisted of grains of titanium diboride located in the intermetallic TiFe matrix.…”