Microstructure and mechanical properties of Ti5Si3 fabricated by spark plasma sintering

The monolithic Ti5Si3 was synthesized by mechanically activated self-propagating high-temperature synthesis (MASHS) from elemental powders and sintered by Spark plasma sintering (SPS) technique. The synthesized powders were sintered at three different temperatures of 1400, 1500 and 1600 °C by SPS with 5 min holding time and reached 84, 91 and 99% of the theoretical density, respectively, while the density of the pressureless sintered sample at 1600 °C reached to 86% after 2 h. The phase composition and microstructural analyses show that titanium silicide retained its phase composition and microstructure during the sintering. The mechanical properties of the compound were measured by the Vickers hardness test and nanoindentation technique. The Young's modulus of 268 ± 8 GPa and nanohardness of 16 ± 1.7 GPa were determined by nanoindentation, while the hardness value of 12.5 ± 0.14 GPa was measured by Vickers indentation test. The crack induced by Vickers indenter was used to measure fracture toughness of the compound and the value of 4 ± 0.1 MPa m1/2 was achieved. The transgranular fracture mode can be identified from the fracture surface of the compound.