PSI - Issue 13

S.M.J. Razavi et al. / Procedia Structural Integrity 13 (2018) 74–78 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

78

5

Table 1. Notch sensitivity results for the tested samples. Δσ 50% * (MPa) K t

K f

q

Unnotched

243

1.073 1.308 2.279

-

-

Semi-circular notch 213

1.141 1.688

0.458 0.538

V notch

144

* fatigue strength at 10 6 cycles.

4. Conclusions

This work aimed to improve the basic understanding of the fatigue behavior of the notched specimens produced with AM techniques by comparing the fatigue data of two different notched specimens produced by Selective Laser Melting technique. The fatigue resistance of SLM produced Ti-6Al-4V notched samples were presented and compared for different notch geometries. Results were compared with those corresponding to smooth samples. Despite the fatigue specimens were weakened by the notches, a low notch sensitivity was observed, which was reported to be correlated to the surface roughness of the AM samples. Ayatollahi, M.R., Razavi, S. M. J., Sommitsch, C., Moser, C., 2017. Fatigue life extension by crack repair using double stop-hole technique. Materials Science Forum 879, 3-8. Ayatollahi, M.R., Razavi, S.M.J., Chamani, H.R., 2014. A numerical study on the effect of symmetric crack flank holes on fatigue life extension of a SENT specimen. Fatigue and Fracture of Engineering Materials and Structures 37(10), 1153-1164. Berto, F., Campagnolo, A., Lazzarin, P., 2015. Fatigue strength of severely notched specimens made of Ti – 6Al – 4V under multiaxial loading. Fatigue and Fracture of Engineering Materials and Structures 38(5), 503-517. Cherolis, N. E., 2008. Fatigue in the Aerospace Industry: Striations. Journal of Failure Analysis and Prevention 8(3), 255 – 258. Kasperovich, G., Hausmann, J., 2015. Improvement of fatigue resistance and ductility of Ti-6Al-4V processed by selective laser melting. Journal of Materials Processing Technology 220, 202-214. Kruth, J. P., Mercelis, P., Van Vaerenbergh, J., Froyen, L., Romboust, M., 2005. Binding mechanism in selective laser sintering and selective laser melting. Rapid Prototyping Journal 11(1), 26-36. Leuders, S., Thöne, M., Riemer, A., Niendorf, T., Tröster, T., Richard, H. A., Maier, H. J., 2013. On the mechanical behaviour of titanium alloy TiAl6V4 manufactured by selective laser melting: fatigue resistance and crack growth performance. International Journal of Fatigue 48, 300 307. Lindgren, L. E., Lundbäck, A., Fisk, M., Pederson, R., Andersson, J., 2016. Simulation of additive manufacturing using coupled constitutive and microstructure models. Additive Manufacturing 12, 144 – 158. Razavi, S.M.J., Ferro, P., Berto, F., 2017. Fatigue Assessment of Ti – 6Al – 4V Circular Notched Specimens Produced by Selective Laser Melting. Metals 7(8), 291. Razavi, S.M.J., Bordonaro, G.G., Ferro, P., Torgersen, J., Berto, F., 2018. Fatigue Behavior of Porous Ti-6Al-4V Made by Laser-Engineered Net Shaping. Materials 11(2), 284. Razavi, S.M.J., Ferro, P., Berto, F., Torgersen, J., (in press). Fatigue strength of blunt V-notched specimens produced by selective laser melting of Ti-6Al-4V. Theoretical and Applied Fracture Mechanics. (DOI: 10.1016/j.tafmec.2017.06.021). Riemer, A., Richard, H.A., Bruggemann, J.P., Wesendahl, J.N., 2015. Fatigue crack growth in additive manufactured products. Frattura ed Integrità Strutturale 34, 437-446. Song, X., Wang, L., Niinomi, M., Nakai, M., Liu, Y., Zhu, M., 2014. Microstructure and fatigue behaviors of a biomedical Ti – Nb – Ta – Zr alloy with trace CeO2 additions. Materials Science and Engineering: A 619, 112 – 118. Spierings, A.B., Starr, T.L., Wegener, K., 2013. Fatigue performance of additive manufactured metallic parts. Rapid Prototyping Journal 19(2), 88-94. Sun, Z., Chemkhi, M., Kanoute, P., Retraint, D., 2014. Fatigue properties of a biomedical 316L steel processed by surface mechanical attrition. Materials Science and Engineering 63, 012021. (DOI:10.1088/1757-899X/63/1/012021) Todai, M., Nakano, T., Liu, T., Yasuda, H. Y., Hagihara, K., Cho, K., Ueda, M., Takeyama, M., 2017. Effect of building direction on the microstructure and tensile properties of Ti-48Al-2Cr-2Nb alloy additively manufactured by electron beam melting. Additive Manufacturing 13, 61 – 70. Wu, X., Liang, J., Mei, J., Mitchell, C., Goodwin, P. S., Voice, W., 2014. Microstructures of laser-deposited Ti-6Al-4V. Materials & Design 25(2), 137-144. Yadollahi, A., Shamsaei, N., 2017. Additive manufacturing of fatigue resistant materials: Challenges and opportunities. International Journal of Fatigue 98, 14 – 31. References