The microstructures and magnetic properties of Zr–Ta binary alloys were examined in the study presented here. The Zr–Ta alloys (Zr-(0–50) mass% Ta) were prepared from 99.5 mass% zirconium and 99.5 mass% tantalum by arc melting in an Ar atmosphere. Magnetic susceptibility was evaluated in air at room temperature. The phase constitutions were identified using an X-ray diffractometer (XRD), a scanning electron microscope (SEM), and a transmission electron microscope (TEM). The acicular martensitic phase formed mainly in the lower Ta composition. In Zr-25Ta and above, the volume fraction of the β-Ta phase increased as Ta concentrations increased. TEM observations showed phase separation due to spinodal decomposition in Zr-20Ta and 30Ta. The diffraction patterns for Zr-20Ta showed spots associated with the ω phase. Magnetic susceptibility gradually declined as Ta was added, falling to a minimum twice: near Zr-20Ta and 50Ta. The former minimum resulted from the high volume fraction of the ω phase having lower magnetic susceptibility than that of other phases. The latter resulted from the formation of the β-Ta phase with magnetic susceptibility lower than the β-Zr phase. As a result, Zr–Ta alloys showed about three times lower magnetic susceptibility than Ti alloys and would be suitable for use with medical devices in MRI environments.
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