Characterization of Mechanical Alloying Processed Ti-Si-B Nanocomposite Consolidated by Spark Plasma Sintering |
Hyung-Bock Lee, In-Jong Kwon, Hyung-Jik Lee1, Young-Hwan Han2 |
Department of Materials Science & Engineering, Myong-Ji University 1Department of Materials Science & Engineering, Kang-Nung University 2Department of Chemical Engineering & Materials Science, University of California |
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ABSTRACT |
The microstructure and mechanical properties of $TiB_2/Si$ nanocomposites based on the Ti-Si-B system, consolidated by spark plasma sintering of mechanically alloyed activated nanopowders, have been characterized. Mechanical Alloying was carried out in a planetary ball mill for 180 min with 350 rev $min^{-1}$. The powders were pressed in vacuum at a pressure of 60 MPa, generating a maximum temperature in the graphite mould of $1400^{circ}C$. Analysis of the synthesized nanocomposites by SEM, XRD and TEM showed them to consist of $TiB_2$ second phase, sub-micron in size, with no third phase. Composites consolidated from powders mechanically alloyed from an initial elemental powder mix of 0.3 mol Si, 0.7 mol Ti, and 2.0 mol B achieved the best relative density (97%) and bending strength (774 MPa); the highest Vickers hardness of 14.7 GPa was achieved for the 0.1-0.9-2.0 mol starting composition. |
Key words:
Spark plasma sintering, Mechanical alloying, Ti-Si-B system, Planetary mill, Activated powder, Nanocomposite |
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