Densification, Sintering Reactions, and Properties of Titanium Diboride With Titanium Disilicide as a Sintering Aid |
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Authors: | G Brahma Raju Bikramjit Basu |
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Affiliation: | Laboratory for Advanced Ceramics, Department of Materials and Metallurgical Engineering, Indian Institute of Technology, Kanpur, India |
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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. |
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