Controlled nanoscale precipitation to enhance the mechanical and biological performances of a metastable β Ti-Nb-Sn alloy for orthopedic applications

Bahl, S and Krishnamurthy, AS and Suwas, S and Chatterjee, K (2017) Controlled nanoscale precipitation to enhance the mechanical and biological performances of a metastable β Ti-Nb-Sn alloy for orthopedic applications. In: Materials and Design, 126 . pp. 226-237.

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Abstract

Toward engineering a new generation of low modulus titanium alloys for orthopedics, we present new insight into the control of nanoscale precipitation in a metastable β Ti-32Nb-2Sn alloy. Nanoscale α precipitates from β phase were obtained by one-step heat treatment at 500 °C. The nanoscale precipitates markedly improve the tensile strength (≈ 1070 MPa) while affording lower modulus (≈ 82 GPa) than conventional metallic biomaterials. Besides age-hardening at 500 °C, an unexpected phenomenon of age-softening is observed even in the presence of nanoscale α precipitates when aged at 600 °C. This effect is attributed to significant softening of the β phase due to compositional changes, as revealed by the elemental mapping in transmission electron microscopy (TEM). TEM elemental mapping reveals that Sn partitions preferentially in the β phase on aging at 500 °C and does not show any preferential partition on aging at 600 °C. The passive layer at the surface enriches in Sn content after aging at 500 °C and consequently affects the electrochemical behavior of the alloy. The alloy supports the proliferation, and osteogenesis of human mesenchymal stem cells. This study provides new understanding for processing Ti-Nb-Sn alloys in biomedical applications

Item Type:	Journal Article
Publication:	Materials and Design
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to the Elsevier Ltd.
Keywords:	Age hardening; Aging of materials; Biocompatibility; Cell culture; Corrosion; Heat treatment; High resolution transmission electron microscopy; Mapping; Medical applications; Nanotechnology; Niobium; Precipitation (chemical); Stem cells; Tensile strength; Tin; Tin alloys; Titanium; Transmission electron microscopy, Biological performance; Biomedical alloys; Biomedical applications; Electrochemical behaviors; Human mesenchymal stem cells; Nano-scale precipitations; One-step heat treatments; Orthopedic applications, Titanium alloys
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	17 Jul 2022 06:19
Last Modified:	17 Jul 2022 06:19
URI:	https://eprints.iisc.ac.in/id/eprint/74508

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