SEM and TEM characterization of microstructure of stainless steel composites reinforced with TiB2

• The steel-8TiB2 composites were fabricated by Spark Plasma Sintering (SPS) and High Pressure-High Temperature (HP-HT).
• Sintering techniques has an important effect on changes in the microstructure of steel-8TiB2 composites.
• New phases of different size and morphology were identified.

Steel-8TiB2 composites were produced by two new sintering techniques, i.e. Spark Plasma Sintering (SPS) and High Pressure-High Temperature (HP-HT) sintering. This study discusses the impact of these sintering methods on the microstructure of steel composites reinforced with TiB2 particles. Scanning electron microscopy (SEM), wavelength dispersive spectroscopy (WDS), X-ray diffraction, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used to analyze the microstructure evolution in steel matrix composites. The results of microscopic examinations revealed a close relationship between the composite microstructure and the methods and conditions of sintering. Substantial differences were observed in the grain size of materials sintered by HP-HT and SPS. It has been demonstrated that the composites sintered by HP-HT tend to form a chromium-iron-nickel phase in the steel matrix. In contrast, the microstructure of the composites sintered by SPS is characterized by the presence of complex borides and chromium-iron phase.