| Densification, microstructural characterization, and the electrochemical behaviour of spark-plasma sintered Ti6Al4V-5Cr-TiB2 composites |
| Oluwasegun Eso Falodun1,2, Samuel Ranti Oke2,3, Olukayode Samuel Akinwamide2,4, Peter Apata Olubambi2 |
1Department of Mechanical Engineering, Covenant University, Ota, Nigeria
2Centre for Nanomechanics and Tribocorrosion, University of Johannesburg, Johannesburg, South Africa
3Centre for Nanomechanics and Tribocorrosion, University of Johannesburg, Johannesburg, South Africa
4Advanced Manufacturing and Materials Research Group, Department of Mechanical Engineering, Aalto University, Espoo, Finland |
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Received: July 28, 2022; Revised: November 21, 2022 Accepted: December 18, 2022. Published online: January 4, 2023. |
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| ABSTRACT |
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The impacts of Cr-TiB2 addition on densification, hardness, microstructure, phase transformation, and corrosion were examined. The results indicated an even and uniform dispersion of TiB2 particles in the titanium matrix, with no noticeable interfaces throughout the sintering process. The relative density of the sintered titanium-based composites dropped, with an increase in TiB2 percentage. The microhardness result indicated that Ti6Al4V has 326 HV0.5, while the maximum hardness was 598 HV0.5, produced from 20 wt.% TiB2 ceramic particles. The Ti6Al4V alloy depicts α-phase forms parallel plates in the prior β-grain borders and expands into the β-grain to create α-colonies, while the addition of 5–20 wt.% Cr-TiB2 resulted in a microstructural transformation characterized by equiaxed α-precipitates embedded within the β-phase matrix, for all samples. The electrochemical behaviour revealed that the Ecorr decreased as TiB2 increased, while the icorr was higher. However, samples containing 5Cr and 5Cr-5TiB2 moved to a more positive E corr region, whereas the icorr altered to a more negative area. This meant that the presence of ceramic reinforcements increased the corrosion resistance of the alloys and that higher concentrations of titanium diboride provided less protection against ion attack in a chloride environment. |
| Key words:
Titanium alloy · Chromium · Ceramic particle · Microstructure · Potentiodynamic behaviour |
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