Angular Deviation and Influential Factors of Burgers Orientation Relationship During Β→Α Transformation in Titanium Alloys

Abstract

The Burgers orientation relationship commonly observed during β→α transformation in titanium alloys exhibits an angular deviation in crystallographic orientation. Determining the possible angular deviations and governing factors is of great importance for controlling the microstructure and properties of alloys. Herein, we propose a calculation method to determine the angular deviations, Δθ, from the ideal Burgers orientation relationship. The calculated results show that the angular deviations exist between the β and α phases in α colonies for Ti-6Al-4V and Ti-6.5Al-2Zr-1Mo-1V alloys. The angular deviations originate from the lattice distortions by the dislocations in the α phase and β phase and their interfaces. Our work indicates that a tolerance angle could be used to determine whether the α phase and β phase obey the Burgers orientation relationship in polycrystalline titanium alloys. The proposed method offers an approach to quantify the variations of the Burgers orientation relationship and develops the understanding of crystallographic evolutions.

Keywords: titanium alloy, Burgers orientation relationship, phase transformation, Lattice distortion, Angular deviation