Figure 3

Representative tensile stress-strain curves of solution treated (ST) and cold rolled plus annealed (CRA) Ti-33Nb-4Sn specimens.
Double yielding can be observed from the ST specimen where the first yielding is associated with a very low yield stress and can be attributed to stress-induced β→α″ martensitic transformation. The second yielding at a higher stress signals the plastic deformation of the material. The CRA specimen exhibits both very high yield and ultimate strengths. Slope of the elastic portion gives a Young’s modulus of only ~36 GPa, very close to that of human bone (~30 GPa).