Microstructure and hot flow stress at 970 °C of various heat-treated Ti2AlNb sheets

• Published in: Rare metals 2020-06, Vol.39 (6), p.695-706
• Main Authors: Wu, Yong, Fan, Rong-Lei, Zhou, Xian-Jun, Chen, Ming-He
• Format: Article
• Language: English
• Subjects: Beta phase; Biomaterials; Chemistry and Materials Science; Creep (materials); Electron backscatter diffraction; Energy; Grain size; Heat treating; Heat treatment; Image transmission; Intermetallic compounds; Materials Engineering; Materials Science; Metallic Materials; Microstructure; Nanoscale Science and Technology; Phase transitions; Physical Chemistry; Plastic deformation; Sheets; Tensile tests; Yield strength
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-020-01408-2

The microstructure and hot tensile behaviors of the different heat-treated Ti 2 AlNb sheets were investigated by backscattered electron image (BSE), electron backscattering diffraction (EBSD), transmission electron microscope (TEM) and tensile tests. The grain sizes and contents of α 2 , B2/β and O phases were quantitatively studied. As the heating time increases at 970 °C, the mean grain size and content of α 2 -phase increased. The grain shapes and distributions of the O-phase lamellar grains were affected by the heat treatments. The plastic deformation promoted the O → B2/β phase transition and the globularization of O-phase lamellar grains at 970 °C. Calculated by the creep equation and the iso-stress method, the grain size exponent was μ = 1.1 and the relationship between the material constants of B2/β and O phase was K O = 1.14 K B 2 / β .