Volume Magnetic Susceptibility Estimation of α- and β-Phases in Titanium Alloys for Biomedical Applications

Metallic medical devices in the human body cause serious artifacts in magnetic resonance imaging owing to the volume magnetic susceptibility (χν) mismatch between the device and tissue around the device. To reduce artifacts, medical devices produced from alloys with χν values of approximately −9 × 10−6 are required. Controlling the phase constitution is a basic technique used to control the χν value of an alloy, and the χν value of each phase is a fundamental property. In this study, an α+β-type Ti alloy and two β-type Ti alloys were investigated. The estimated χν values of the α-phase of the alloys were similar to or smaller than that of pure Ti. In contrast, the estimated χν values of the β-phase of the alloys were larger than that of pure Ti. Since the χν value of pure Ti is much larger than −9 × 10−6, the χν values of the β-phases suggested that increasing the volume fraction of the β-phase was not appropriate for producing a Ti alloy with a lower χν value.

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本論文は，著者Muneyuki Yoshimuraの学位論文として提出され，学位審査・授与の対象となっている。