Texture evolution of orthorhombic α″ titanium alloy investigated by in situ X-ray diffraction

The present paper deals with an in-situ X-ray diffraction analysis during cyclic tensile tests of a fully martensitic Ti-24Nb alloy. Texture evolution of martensite α″ phase was followed during loading-unloading cycles. Preferential formation and reverse transformation of particular martensite variants have been observed based on pole figure analysis. The occurrence of the deformation mechanisms for the martensitic Ti-24Nb alloy was also commented by coupling microstructural observations during in-situ experiments and additional cyclic tests followed by heating after each unloading. Through the study of the evolution of the lattice strain, it was found that under loading conditions, the {020} planes exhibit a large tension lattice strain while the {200} planes are subjected to a compression solicitation, which causes the lattice parameters a and c to be shrunk, and b to be elongated.