A study on the micromechanical behavior of Ti-55531 titanium alloy with lamellar microstructure by in-situ neutron diffraction

^a Beijing Advanced Innovation Center for Materials Genome Engineering, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
^b J-PARC Center, Japan Atomic Energy Agency, 2-4, Shirane Shirakata, Tokai, Ibaraki 315-1195, Japan
^c Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999, China

Abstract

High strength titanium alloys are promising materials for heavy component parts in the aviation industry. The limited combination of strength and ductility requires an understanding of deformation and stress partitioning between constituent phases. The micromechanical behaviors of Ti-55531 titanium alloy with lamellar microstructure are investigated by in-situ neutron diffraction. The phase strain and lattice strain evolution of α and β phase at loading direction and transverse direction are determined. The results show that the micromechanical behaviors of oriented grains of α and β phase are obviously different. Furthermore, the stress partitioning between α and β phase during the deformation is clearly illustrated. It is found that the β matrix is subjected to higher stress than α precipitates. In addition, the intergranular and interphase microstress is quantitatively characterized. It is found that the intergranular microstress in the β phase grains is predominant among these microstresses. Combining the in-situ neutron diffraction with microstructure characterization, the present work provides a guide for further microstructure optimization.