Densification, Sintering Reactions, and Properties of Titanium Diboride With Titanium Disilicide as a Sintering Aid

In the present investigation, we explore the feasibility of using TiSi 2 as a sintering aid to densify titanium diboride (TiB 2 ) at a lower sintering temperature (<1700°C). The hot‐pressing experiments were conducted in the temperature range of 1400°–1650°C for 1 h in an argon atmosphere and TiSi 2 addition to TiB 2 was restricted up to 10 wt%, with an overall objective to densify the materials with a fine microstructure as well as to assess the feasibility of enhancing the mechanical and electrical properties. When all the materials were hot pressed at 1650°C, the hot‐pressed TiB 2 – X % TiSi 2 ( X =0, 2.5, 5, 10 wt%) composites were found to be densified to more than 98%ρ th (theoretical density), except monolithic TiB 2 (∼94%ρ th ). An interesting observation is the formation of a Ti 5 Si 3 phase and this phase formation is described by thermodynamically feasible sintering reactions. Our experimental results suggest that the optimal TiB 2 –5 wt% TiSi 2 composite can exhibit an excellent combination of properties, including a high hardness of 25 GPa, an elastic modulus of 518 GPa, an indentation toughness of ∼6 MPa·m 1/2 , a four‐point flexural strength of more than 400 MPa, and an electrical resistivity of 10 μΩ·cm.