Microstructure and properties of as‐cast Zr‐2.5Nb‐1X (X = Ru, Mo, Ta and Si) alloys for biomedical application

The microstructure and properties of as‐cast Zr‐2.5Nb‐1X (X = Ru, Mo, Ta and Si) alloy are screened to explore novel biomedical zirconium alloys for magnetic resonance applications. Corresponding microstructure and phase transformation were characterized using X‐ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Hardness test, magnetic detection and electrochemical corrosion measurements are taken to present properties. The results show that all alloys consist of α‐Zr, β‐Zr and ω‐Zr. α‐Zr and β‐Zr mainly exist in the form of parallel and intersecting plates, and nanoscale ω‐Zr is dispersed in β‐Zr plate. Especially, blocky ω‐Zr with needle‐like α‐Zr is only found in plate‐free blocks of Zr‐2.5Nb‐1Mo/Ru alloy. The orientation relationship (OR) between α‐ Zr and ω‐Zr follows // and //( 011) ω . Combining this OR with the OR between β‐Zr and ω‐Zr, the transformation relationship between β‐Zr/ω‐Zr and α‐Zr is also discussed. Zr‐2.5Nb‐1Ru alloy with high corrosion potential (− 0.500 V), low corrosion rate (0.949 μm·year –1 ) and low magnetic susceptibility (92 × 10 −6 ) shows great potential to be a novel biomedical implant with magnetic resonance imaging compatibility. Based on the experimental results, the possible relationship among alloying elements, microstructure and properties has been established in these Zr‐2.5Nb‐1X alloys.