PSI - Issue 57

Wilmer Velilla-Díaz et al. / Procedia Structural Integrity 57 (2024) 461–468

467

Velilla-D´ıaz & Zambrano / Structural Integrity Procedia 00 (2023) 000–000

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4. Conclusions

In conclusion, this study aimed to investigate the e ff ect of grain boundaries (GBs) on fatigue crack growth in aluminum bi-crystals. Through molecular dynamics (MD) simulations, the mechanical behavior and deformation mechanisms of bi-crystals with di ff erent tilt and twist GB angles were analyzed. The results demonstrated di ff erent e ff ects of low and high tilt and twist GB angles on fatigue crack growth. • For low tilt angles (5° and 10°), the GBs did not impede crack growth, indicating that the global stress required to fracture the bi-crystal occurred beyond the first crystal. • For high tilt angles, the GBs acted as barriers, e ff ectively halting crack propagation. In these cases, the stress needed to continue crack propagation had to surpass a critical threshold at the first tearing event along the GB. • Twist grain boundaries with angles higher than 5° have a remarkable ability to impede fatigue crack growth in aluminum bi-crystals. The presence of these GBs can lead to a significant enhancement in fatigue resistance, with materials exhibiting more than a three-fold improvement compared to those without such GBs or with high tilt angles as shown in Figure 6. These findings highlight the significant influence of GBs on the fatigue crack growth behavior of aluminum bi crystals. Understanding the role of GBs in crack propagation is crucial for designing and engineering materials with improved fatigue resistance. The results provide valuable insights for the development of advanced materials with tailored grain boundary properties. Berman, D., Krim, J., 2013. Surface science, mems and nems: Progress and opportunities for surface science research performed on, or by, microdevices. Progress in Surface Science 88, 171–211. URL: http://dx.doi.org/10.1016/j.progsurf.2013.03.001 , doi: 10.1016/ j.progsurf.2013.03.001 . Chandra, S., Kumar, N.N., Samal, M.K., Chavan, V.M., Raghunathan, S., 2017. 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