中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 36 No. 2 February 2026 |
（a National & Local Joint Engineering Laboratory for High-performance Metal Structure Materials and Advanced Manufacturing Technology, Guizhou University, Guiyang 550025, China;
b School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China;
c School of Materials and Energy Engineering, Guizhou Institute of Technology, Guiyang 550003, China;
d School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore 639789, Singapore）
Abstract:The interrupted fatigue test method was utilized to investigate the damage evolution mechanism of the notch high-cycle fatigue (NHCF) in Ti-55531 alloy with a multilevel lamellar microstructure. The results reveal that significant microvoids and microcracks predominantly initiate at α/β interfaces under various notch root radii (R). Notably, even under larger R (0.75 mm), mutual interactions of stacking faults (SFs)-deformation twins, twins-twins, and SFs-SFs are observed. Furthermore, with decreasing R (0.34 and 0.14 mm), the volume fraction of SFs escalates significantly and twins are almost absent. Moreover, activated prismatic slip system decreases with a decrease in Schmidt factor and with the further decrease in R. Finally, strain localization near α/β interfaces contributes to the initiation of fatigue microcracks.
Key words: damage mechanism; Ti alloy; interrupted fatigue; crack initiation; stacking fault; twin; prismatic slip system
