Microstructure and mechanical properties of as-cast Zr-Nb alloys

Ryota Kondo, Naoyuki Nomura, Suyalatu, Yusuke Tsutsumi, Hisashi Doi, Takao Hanawa

Research output: Contribution to journalArticlepeer-review

108 Citations (Scopus)

Abstract

On the basis of the microstructures and mechanical properties of as-cast Zr-(0-24)Nb alloys the effects of phase constitution on the mechanical properties and magnetic susceptibility are discussed in order to develop Zr alloys for use in magnetic resonance imaging (MRI). The microstructures were evaluated using an X-ray diffractometer, an optical microscope, and a transmission electron microscope; the mechanical properties were evaluated by a tensile test. The α′ phase was dominantly formed with less than 6 mass% Nb content. The ω phase was formed in Zr-(6-20)Nb alloys, but disappeared from Zr-22Nb. The β phase dominantly existed in Zr-(9-24)Nb alloys. The mechanical properties as well as the magnetic susceptibility of the Zr-Nb alloys varied depending on the phase constitution. The Zr-Nb alloys consisting of mainly α′ phase showed high strength, moderate ductility, and a high Young's modulus, retaining low magnetic susceptibility. Zr-Nb alloys containing a larger volume of ω phase were found to be brittle and, thus, should be avoided, despite their low magnetic susceptibility. When the Zr-Nb alloys consisted primarily of β phase the effect of ω phase weakened the mechanical properties, thereby leading to an increase in ductility, even with an increase in magnetic susceptibility. The minimum value of Young's modulus was obtained for Zr-20Nb, because this composition was the phase boundary between the β and ω phases. However, the magnetic susceptibility of the alloy was half that of Ti-6Al-4V alloys. Zr-Nb alloys consisting of α′ or β phase have excellent mechanical properties with low magnetic susceptibility and, thus, these alloys could be useful for medical devices used in MRI.

Original languageEnglish
Pages (from-to)4278-4284
Number of pages7
JournalActa Biomaterialia
Volume7
Issue number12
DOIs
Publication statusPublished - 2011 Dec
Externally publishedYes

Keywords

  • Magnetic susceptibility
  • Mechanical properties
  • Microstructure
  • Phase constitution
  • Zr-Nb alloy

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology

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