Stress-Induced Martensitic Transformation of Metastable Ti-Nb-Ge Alloys for Biomedical Application
Pseudoelastic behavior of Ti-xNb-yGe alloys, where x=22~28at.% and y=0.5~2.0at.%, was investigated by controlling martensite start temperature and phase stability of β phase. Cyclic tensile test was carried out to display a pseudoelastic behavior at room temperature. Determination of the martensitic transformation temperature (Ms and Mf) and reverse transformation temperature (As and Af) of the alloys were carried out using differential scanning calorimetry (DSC). Optical microscopy, X-ray diffraction (XRD) and DSC results revealed that Ge is stronger stabilizer of β-phase than Nb. XRD spectra of the deformed specimens confirmed that the crystal structure of stress-induced martensite phase is orthorhombic structured α″. It is concluded that pseudoelasticity of the present Ti-Nb-Ge alloy is closely associated with phase stability, and metastable β-phase is better to increase pseudoelasticity than stable one.
Byungsei Jun, Hyungsun Kim, Chanwon Lee, Soo Wohn Lee
H. S. Kim and W. Y. Kim, "Stress-Induced Martensitic Transformation of Metastable Ti-Nb-Ge Alloys for Biomedical Application", Materials Science Forum, Vol. 569, pp. 145-148, 2008