Ultra-fine grained β-type TNZT ELI alloy with high strength and low elastic modulus

5th International Conference Recent Trends in Structural Materials

Polyakov, A.V.^1 ; Semenova, I.P.^1 ; Ivanov, E.^2 ; Valiev, R.Z.^1

Ufa State Aviation Technical University, Institute of Physics of Advanced Materials, 12 K. Marx str., Ufa

450008, Russia^1

Tosoh SMD Inc., 3600 Gantz Road, Grove City

OH

43123, United States^2

关键词: High pressure torsions;    Low elastic modulus;    Nano-structured;    Omega transformations;    Severe plastic deformations;    Subgrain structures;    Ultimate tensile strength;    Ultra-fine-grained;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/461/1/012077/pdf
DOI  :  10.1088/1757-899X/461/1/012077

来源: IOP

【 摘 要 】

This work deals with the improvement of mechanical properties of medical alloy Ti-34Nb-7Zr-4.6Ta ELI (TNZT) by severe plastic deformation (SPD) techniques at temperatures below the temperature of the onset of phase transformations in order to maintain a low modulus of elasticity. For the formation of a nanostructured state, high pressure torsion (HPT) at room temperature and equal channel angular pressing (ECAP) at 200 °C, that is, below the onset of diffusion ω-transformation, were used. It is shown that HPT leads to the formation of the UFG structure in the alloy with the grain size of about 110 nm without changing in the alloy phase composition. The ECAP processing allowed forming a subgrain structure with an average size of grains/subgrains of 500 nm and an ultimate tensile strength of 745 MPa, which exceeded the ultimate tensile strength after the standard aging in the (α+β) area (686 MPa). The issues of the effect of SPD on changes in the structure, phase transformations in the alloy and ways of maintaining a low modulus of elasticity in this alloy are discussed.