Effect of ECAP and annealing on structure and mechanical properties of metastable beta Ti-18Zr-15Nb (at.%) alloy

• DOI: 10.1016/j.matlet.2021.130760
• Publication Date: 2021-08-27T07:10:23Z
• Authors: V. Sheremetyev; A. Churakova; M. Derkach; D. Gunderov; G. Raab; S. Prokoshkin
• Keywords: 0103 physical sciences; 01 natural sciences

Abstract Effect of ECAP at 250 °C and annealing on structure and mechanical properties of the Ti-18Zr-15Nb biomedical alloy has been studied. The XRD and TEM data shows that ECAP leads to the formation of a predominantly nanocrystalline structure composed of equiaxed structure elements (grains and subgrains) of β-phase whose diameter ranges from 20 to 100 nm with some amount of α″- and ω-phases. In this structural state, the alloy exhibits high strength (YS = 962 MPa, UTS = 988 MPa). Additional annealing after ECAP at 525 °C (5 min) forms a submicrocrystalline structure (100–400 nm-diam. grains) of β-phase which promotes reducing of strength (YS = 526 MPa, UTS = 835 MPa) and increase in ductility.