Event Abstract

Back to Event

MRI artifact-free Au-Nb-Ti alloy of high hardness for biomedical applications

Kenichi Hamada1, Shihoko Inui1*, Emi Uyama1* and Eiichi Honda2
  • 1 Institute of Biomedical Sciences, Tokushima University Graduate School, Department of Biomaterials and bioengineering, Japan
  • 2 Institute of Biomedical Sciences, Tokushima University Graduate School, Department of Oral and Maxillofacial Radiology, Japan

Introduction: Mismatch between the volume magnetic susceptibility (χv) of biomedical devices and the surrounding tissue in a human body causes a serious artifact in magnetic resonance imaging (MRI). The authors have developed Au-Nb alloys with χv values similar to that of human tissue [approximately -9 × 10-6, (-9 ppm)] and with excellent hardness of approximately 230HV (Vickers hardness). However, HV of the alloy is lower than those of typical alloys of high hardness for biomedical applications; Ti-6Al-4V alloy (approximately 320HV) and Co-Cr alloy (Vitallium®, approximately 430HV). In the present study, the effects of Ti addition on HV,  χv and phase constitution of Au-Nb-Ti alloy were investigated.

Experimental Methods: Au-xNb-yTi (x = 4, 8 and 12, y = 1, 1.5 and 2) alloy ingots were fabricated by argon-arc-melting. The ingots were rolled at 573 K in air to a thickness of approximately 1-1.5 mm. The total rolling reduction was 50-70%. The rolled alloy plates were homogenized at 1273 K for 20 h. Aging treatments were performed at 873 K and 1073 K. The χv values were measured using a magnetic susceptibility balance; the HV was measured under a load of 100 g for 30 s; and the phase constitution was analysed using X-ray diffractometry (XRD).

Results and Discussion: The χv values of Au-4Nb-yTi alloys were close to -9 ppm, and Ti content and aging treatment did not affect on them. The HV value of the alloys was close to or less than 230. Au-8Nb-yTi alloys after homogenizing indicated positive χv values, and only Au-8Nb-1Ti alloy indicated χv value close to -9 ppm after aging treatment. However, HV of the alloy after aging treatment did not exceed 230. Au-12Nb-1Ti alloy indicated χv value close to 0 ppm and insufficient HV, simultaneously. Au-12Nb-2Ti alloy indicated χv value close to -9 ppm after aging treatment, however, solution treatment could not be performed, and therefore, it showed low rollability.

Only Au-12Nb-1.5Ti alloy exhibited excellent properties; the χv values of the alloy after aging treatment at 673 K and 873 K for 30 m were close to -9 ppm, and the HV values were higher than 400. The phase constitution of the alloy after homogenization was single phase, and it showed sufficient rollability. Both Au2Nb intermetallic compound (IMC) and unknown IMC were precipitated after aging treatment.

Conclusion: Addition of Ti to Au-Nb alloy is effective for increasing HV without serious magnetic susceptibility mismatch, and helps achieve a MRI artifact-free alloy with high hardness.

Acknowledgments: A part of this work was financially supported by JSPS KAKENHI, Japan Science and Technology Agency, Tanaka Kikinzoku Research Fund and Terumo Life Science Foundation.

JSPS; Japan Science and Technology Agency; Tanaka Kikinzoku Research Fund; Terumo Foundation for Life Sciences and Arts.

Keywords: MRI, biomedical application, mechanical property

Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016.

Presentation Type: General Session Oral

Topic: Metallic biomaterials and alloys

Citation: Hamada K, Inui S, Uyama E and Honda E (2016). MRI artifact-free Au-Nb-Ti alloy of high hardness for biomedical applications. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01409

Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.

The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.

Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.

For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.

Received: 27 Mar 2016; Published Online: 30 Mar 2016.

* Correspondence:
Dr. Shihoko Inui, Institute of Biomedical Sciences, Tokushima University Graduate School, Department of Biomaterials and bioengineering, Tokushima, Japan, c301251012@tokushima-u.ac.jp
Dr. Emi Uyama, Institute of Biomedical Sciences, Tokushima University Graduate School, Department of Biomaterials and bioengineering, Tokushima, Japan, uyamanikofu@tokushima-u.ac.jp