文献类型：期刊文献

英文题名：Study on Fatigue Performance and Dislocation Evolution Mechanism of Nanoscale Nickel-Based Superalloys in Cryogenic Conditions

作者：Zhang P.; Jiang X.; Zhang T.; Yu Y.; Lan C.

机构：[1]College of Mechanical and Power Engineering, Guangdong Ocean University, Zhanjiang, 524091, China;[2]College of Intelligent Manufacturing, Qingdao Huanghai University, Qingdao, 266520, China

年份：2026

卷号：21

期号：1

外文期刊名：Nano

收录：Scopus(收录号：2-s2.0-85213269622)

语种：英文

外文关键词：dislocation evolution; fatigue performance; grain number; Molecular dynamics simulation; strain amplitude

外文摘要：This study investigates the fatigue performance and dislocation evolution mechanisms of nanoscale nickel-based superalloys at cryogenic temperatures. Utilizing molecular dynamics simulations, we examined how grain number, strain amplitude and the number of cycles affect the fatigue behavior of these alloys. Shear strain contour maps and atomic structure evolution maps were employed to conduct a quantitative analysis of the fatigue process at 77 K, considering various grain numbers (ranging from 100 to 300) and strain amplitudes (spanning from 50 ? to 100 ?). The findings reveal that an increase in grain number reduces the range of shear strain concentration, with the concentrated regions extending from the sample notch to the sides. Larger strain amplitudes and more cycles amplify the range and degree of strain concentration and promote the extension of strain-concentrated areas toward the sides. Additionally, increased strain amplitude results in a higher proportion of BCC atoms, while FCC atoms remain the dominant structure. The grain number significantly influences dislocation evolution maps; with grain numbers exceeding 150, there is an increase in the formation of dislocation walls and loops, and a reduction in dislocation numbers in the notch area. Furthermore, as the strain amplitude increases, there is a decreasing trend in the total dislocation count, while the length of 1/2h110i (Perfect) dislocations increases significantly. The maximum density of 1/6h112i (Shockley) dislocations for a grain number of 250 is substantially higher than that for other grain numbers, about 1.55 times greater than the density for a grain number of 300. ? 2026 World Scientific Publishing Company.