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

Abstract

In the present investigation, we explore the feasibility of using TiSi2 as a sintering aid to densify titanium diboride (TiB2) 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 TiSi2 addition to TiB2 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 TiB2–X% TiSi2 (X=0, 2.5, 5, 10 wt%) composites were found to be densified to more than 98%ρth (theoretical density), except monolithic TiB2 (∼94%ρth). An interesting observation is the formation of a Ti5Si3 phase and this phase formation is described by thermodynamically feasible sintering reactions. Our experimental results suggest that the optimal TiB2–5 wt% TiSi2 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·m1/2, a four‐point flexural strength of more than 400 MPa, and an electrical resistivity of 10 μΩ·cm.