Cyclic deformation and lattice strain distribution of high Nb containing TiAl alloy

• Main Authors: Ding, Jie, Shi, Shan, Dong, Zhili, Lin, Junpin, Ren, Yang, Wu, Xiaodong, Chang, Hui, Zhou, Lian
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Materials; TiAl Alloys; Low Cycle Fatigue
• Online Access: https://hdl.handle.net/10356/144616
• Institution: Nanyang Technological University

Low cycle fatigue of lamellar TiAl with 8.5 at.-%Nb was studied with a total strain amplitude of 0.28% at three temperatures: room temperature, 750°C and 900°C. At room temperature, the material exhibited cyclic hardening and the fracture mode was mainly interlamellar. At 750°C and 900°C, the material showed cyclic softening and the fracture mode was translamellar. The lattice strain in γ phase was almost tensile and larger tensile lattice strain in γ phase seems detrimental. Besides, the opposite direction of {201}γ and {100}α2 lead to crack propagation along α2/γ interfaces. B2/βo phase always suffered compressive lattice strain in the tests. The destruction of lamellar microstructure was the reason for colony refinement at 750°C and 900°C.