Abstract
In this study, an attempt has been made for tailoring the surface features of an 18 vol% porosity containing Ti[sbnd]23Nb alloy manufactured via powder metallurgy method. The aim was enhancing the wear resistance without sacrificing the mechanical properties. For this purpose, porous Ti[sbnd]23Nb alloys having hardness of 280 HV0.025 were subjected to thermal oxidation (TO) at 600 °C in air for two different holding times. TO duration of 6 h, which introduced a ~ 0.5 μm thick TiO2-rutile type exterior oxide layer (OL), provided surface hardness of 620 HV0.025. Extension of TO duration to 60 h caused covering of the surfaces with a ~ 3.0 μm thick OL and increase of surface hardness to 980 HV0.025. As the result of the increased surface hardness, TO'ed. alloys showed superior sliding wear resistance coupled with a reduction in friction coefficient (COF) against alumina ball in 1.5× simulated body fluid (SBF) when compared to the as-sintered state. Despite having the highest surface hardness, the alloy TO'ed. for 60 h exhibited slightly higher wear loss and COF than the alloy TO'ed. for 6 h. More important than this, the alloy TO'ed. for 60 h collapsed at a compressive stress well below the yield strength of the alloy TO'ed. for 6 h, which exhibited almost similar compressive stress-strain curve with that of the as-sintered alloy. From this perspective 6 h appeared as a promising TO duration for the examined porous alloy to be used in biomedical applications as it preserves the mechanical properties while providing remarkable enhancement in the wear resistance.
Original language | English |
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Article number | 128429 |
Journal | Surface and Coatings Technology |
Volume | 439 |
DOIs | |
Publication status | Published - 15 Jun 2022 |
Bibliographical note
Publisher Copyright:© 2022 Elsevier B.V.
Funding
Dr. M. K. Ibrahim acknowledges the scholarship provided by Türkiye Scholarships during his postdoc studies under the supervision of Dr. H. Cimenoglu at Istanbul Technical University. For Raman analyses MSc. B. Avci and Dr. M. Urgen and for SEM investigations MSc. G. Soydan and Dr. N. Solak are highly appreciated. Also, authors would like to thank Karfo Endüstriyel Co. for their technical support about detailed SEM examinations.
Funders | Funder number |
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Istanbul Teknik Üniversitesi |
Keywords
- Porous alloys
- Simulated body fluid
- Thermal oxidation
- Ti-Nb alloys
- Wear