Abstract
Unlocking the full potential of intermetallic TiAl alloys in aerospace and automotive engines demands critical
attention, as their limitations, particularly due to the room temperature brittle nature, inadequate oxidation and
strength beyond 800 ◦C. Hence, the need to improve the mechanical properties is crucial to expanding their
versatile applications. Herein, the effect of Niobium nitride (NbN) addition on the densification, microstructure,
and mechanical characteristics of Titanium aluminide (TiAl) was studied. TiAl powders with various concentrations
of NbN at 0, 2, 4, 6, 8, and 10 wt.% were synthesized through the spark plasma sintering technique. Each
blended composite powder was measured according to stoichiometry into a 30 mm internal diameter graphite
die and sintered at a temperature of 1150 ◦C, a pressure of 50 MPa, a heating rate of 100 ◦C/min, and a dwell
time of 10 mins. The densification phenomenon, phase present, microstructure, and mechanical properties were
investigated via Archimedes’ principle, X-ray diffraction (XRD), and Vickers hardness tester, respectively. Results
shows that the addition of NbN to TiAl at constant sintering parameters enhanced the mechanical properties of
TiAl. The microhardness of the composite material increases as the NbN addition increases, with maximum
hardness of 467 HV, and ultimate tensile strength (UTS) up to 1458.9 MPa, attained at 10 wt.% NbN addition.
Maximum porosity content of an impressive 1.6% was recorded at the addition of 10 wt.% NbN, which shows
exceptional efficiency of spark plasma sintering technique. The results on densification and mechanical properties
are presented and discussed with respect to the material composition and processing condition of the
sintered materials.