Mechanics of superelasticity in Ti–30Nb–(8–10)Ta–5Zr alloy Original Research Article

The superelastic behaviour of Ti–30Nb–10Ta–5Zr and Ti–30Nb–8Ta–5Zr (wt.%) biomedical alloys was investigated by tensile testing and in situ synchrotron X-ray diffraction. The phenomenological theory of martensite crystallography and texture prediction based on the Schmid law indicate that image in Ti–30Nb–10Ta–5Zr forms in untwinned variants. Measurement of single-crystal elastic constants using an Eshelby–Kroener–Kneer self-consistent model shows that the 10-Ta alloy has a image modulus 3 GPa higher than that of the 8-Ta alloy. That it nevertheless has a proof stress 35 MPa lower can be qualitatively explained by the differences in martensite crystallography. The results suggest that high tensile strength can be maintained for low modulus image in spite of martensitic transformation by optimizing transformation strains.