Effect of (Ti:B) atomic ratio on mechanical properties of TiB2–Fe composites “in situ” fabricated via Self-propagating High-temperature Synthesis

• The Fe2B in TiB2–Fe cermets was caused by solubility of a few at.% of Ti in Fe matrix.
• Phase constituents of TiB2–Fe cermets were moderated by Ti:B atomic ratio.
• The formation of Fe2B was eliminated by Ti excess (Ti:B at. ratio of 0.525).
• Maximum bending strength attained composite having avoided both Fe2B and Fe2Ti.
• Increasing Ti:B at. ratio caused deteriorating strength under compression.

The TiB2-based Fe–matrix cermets with titanium addition (literarily different Ti:B ratio) were fabricated from elemental powders “in situ” using the Self-propagating High-temperature Synthesis method (SHS) under high pressure. The effect of Ti:B ratio on microstructure and phase composition with particular focus on matrix phase were analyzed using X-ray diffraction (XRD) and Wavelength Dispersive Spectroscopy (WDS) for composites with intended 25 vol.% and 35 vol.% of Fe. Moreover, for composites with 35 vol.% of Fe bending strength and compressive strength were investigated. The compressive strength reached maximum value in material with Ti:B atomic ratio of 0.49, which possessed the highest TiB2 content and matrix phase consisting of Fe and Fe2B. However, modulus of rupture (MOR) test indicated that composite with titanium excess (Ti:B atomic ratio of 0.525) was characterized by the highest bending strength, due to successful elimination of Fe2B intermetallics.