**8. Conclusions**

The process of TaC powder synthesis generated microstructure of refined grains with rounded morphology of particles, and crystallite size (13.78 nm) that may have influenced densification and also the microhardness of sintered samples.

Tantalum carbide-TaC with nanosized crystallites, strongly agglomerated, forming particles smaller than EUROFER 97 steel particles, were dispersed by milling, remaining compacted among particles that compose the metal matrix, thus obtained material with refined micro‐ structure, smaller grain sizes and good mechanical properties.

SEM images show sintered pure steel samples and steel composites with UFRN TaC, in which microstructure typical of sintered material with initial, intermediate, final sintering stages were observed. In addition, the dispersion of tantalum carbides in the EUROFER steel metal matrix was observed.

Optical microscopy showed a change in grain size and in the microstructure of the different sintered materials. For samples with the addition of TaC, grain size decreased or remained stable compared with sintered pure steel. Sintering at temperature of 1250°C provided high densification in composite reinforced with Aldrich TaC but the microhardness result was low, which can be related to a phase change, i.e. steel became fully ferritic.

The powder metallurgy processing was sufficient to improve the mechanical properties of EUROFER steel, with small difference in relation to microhardness results between EUROFER steel and composite reinforced with UFRN TaC. In the case of composite reinforced with commercial TaC, there is a considerable difference, which can be related to the phase trans‐ formation and / or presence of coarse particles compared with UFRN TaC powder particles, which are thinner.

New EUROFER 97 steel composite with TaC was developed and characterized according to appropriate procedures for the manufacturing processes used in this work and with altered mechanical properties and future features such as: special applications in nuclear reactor, cutting materials and many others.
