I am very confused about this question. In some articles, it is stated that single slip is reversible in deformation, while multiple slip is irreversible, and multiple slip will increase the accumulation of fatigue damage. However, in other articles, it is mentioned that single slip has limited ability to coordinate plastic deformation, while multiple slip can make the material deform more uniformly, thus multiple slip is beneficial for fatigue life. These two viewpoints are contradictory in their conclusions, which makes me very puzzled.
Thank you for your answer !!!
Single or multiple benefits fatigue life depends on numerous factors, such as material, temperature profile, loading conditions, grain size and orientation, and fatigue regime. However, the rationale between the two for a single slip advocates reversible deformation, and lessens localized strain concentration, while multiple distributes deformation more uniformly, and enhances strain hardening. Also, single slip delays crack initiation, while multiple improves fatigue life by reducing strain localization.
References:
(1) Mura, T., et al. (2013). Fatigue crack initiation and growth in single crystals: A review. International Journal of Fatigue, 50, 1-13.
(2) Mughrabi, H., & Ungar, T. (2002). Cyclic deformation and fatigue crack initiation in polycrystalline copper. Materials Science and Engineering A, 328(1-2), 179-186.
(3) Kaneko, D., et al. (2017). Cyclic plasticity and fatigue of metals: A review. Journal of Materials Science, 52(10), 5511-5534.
(4) Mughrabi, H. (1978). Strain hardening and fatigue behavior of copper single crystals. Materials Science and Engineering A, 33(1), 207-215.
(5) Liu, J. M., et al. (2015). Fatigue behavior of single-crystal nickel-based superalloys. International Journal of Fatigue, 80, 337-345.
(6) Srivatsan, T. S., et al. (2006). Fatigue behavior of polycrystalline metals: The role of grain size and texture. International Journal of Fatigue, 28(10), 1452-1462.