Design and fabrication of a low modulus β-type Ti–Nb–Zr alloy by controlling martensitic transformation

In this paper, high density of dislocations, grain boundaries and nanometer-scale α precipitates were introduced to a metastable Ti–36Nb–5Zr alloy (wt%) through a thermo-mechanical approach including severe cold rolling and short-time annealing treatment. The martensitic transformation was retarded, and the β phase with low content of β stabilizers was retained at room temperature after the thermo-mechanical treatment. As a result, both low modulus (57 GPa) and high strength (950 MPa) are obtained. The results indicate that it is a feasible strategy to control martensitic transformation start temperature through microstructure optimization instead of composition design, with the aim of fabricating low modulus β-type Ti alloy.