Abstract
This study is aimed at designing a series of metastable β-type Ti-Mo-Nb-Zr alloy series with low elastic moduli as potential alternatives for conventional orthopaedic implant materials including 316L stainless steel, cobalt-chromium and Ti6Al4V. The most important concerns associated with these materials during long term implantation are cytotoxicity and stress-shielding effect resulting from the imbalance of the elastic moduli with those of the human bone, which can cause bone resorption and implant failure. The alloys in this were designed using a synergic combination of approaches (cluster-plus-glue-atom model cluster formula [(Mo)(Ti14-xZrx)]TiyNbz and β stability predicting theories including molybdenum equivalence, d-electron theory and average electron concentration ratio) instead of using trial-and-error method with no fundamental basis, which is time-consuming and costly during manufacturing. For the identification of the phase constituents, X-ray diffraction analysis was carried out, whereas the microstructural characterization was performed using the scanning, electron microscopy, and optical microscopy and electron backscatter diffraction techniques. The mechanical properties including microhardness, tensile properties, bending properties and compressive properties were also investigated...
Ph.D. (Engineering Metallurgy)