Issue 43

B. Saadouki et alii, Frattura ed Integrità Strutturale, 43 (2018) 133-145; DOI: 10.3221/IGF-ESIS.43.10 143 b c Morrow Tomkins Manson-Coffin Morrow Tomkins Manson-Coffin -0.09 -0.1 -0.12 -0.59 -0.79 -0.6 Table 5 : Comparison of the SICLANIC ® fatigue exponent by different formulas. The values of b and c suggested by Manson-Coffin are close to those obtained by using Morrow and Tomkins relations. These numerical expressions based on the coefficient of hardening ݊ ′ calculated experimentally are in good agreement with the Manson-Coffin approximations. C ONCLUSIONS echanical characterization of SICLANIC ® proves that it is an alloy with high tensile characteristics. However, in cyclical loading, material shows moderate fatigue resistance. Results for fatigue analysis summarized as follows: 1. The mechanical properties (yield strength, hardening coefficient) of the SICLANIC ® are considerably modified by the application of high stress cycles, even in small numbers. The SICLANIC ® is softened under the fatigue loading. Hardening coefficient calculation with analytical models also predicts SICLANIC ® softening phenomena. 2. If certain cycles reach stress levels close to or even more than YS 0.2 , we can meet a softening behavior, so a lowering of The YS 0.2 up to YS’ 0.2 . High stress levels can cause harmful and permanent deformations to the proper functioning of the part. 3. The fractography analysis of the SICLANIC ® specimens exhibits a transgranular failure during a cyclic solicitation. Fractures arise at the grain boundaries, and flat surfaces in the crystalline material confirms the cleavage failure. A CKNOWLEDGEMENTS uthors acknowledge the funding for COILTIM project from “Région Picardie” and “Le fonds européen de développement économique et régional (FEDER)”. R EFERENCES [1] Hornbogen, E., Hundred years of precipitation hardening. Journal of light Metal, 11 (2010) 127–132. [2] Lockyer, S.A., Noble, F.W., Fatigue of precipitate strengthened Cu-Ni-Si alloy, Materials Science and Technology, 15 (1999) 1147-1153. DOI: 10.1179/026708399101505194 [3] Batawi, E., Morris, D.G., Morris, M.A., Effect of small alloying additions on behavior of rapidly solidified Cu-Cr alloys, Materials Science and Technology, 6 (1990) 892-899. DOI: 10.1179/mst.1990.6.9.892 [4] Lee, K.L., Whitehouse, A.F., Withers, P.J., Daymond, M.R., Neutron diffraction study of the deformation behavior of deformation processed copper–chromium composites, Materials Science and Engineering, A384 (2003) 208-216. DOI: 10.1016/S0921-5093 (02)00688-3 [5] Chen, X.P., Sun, H.F., Wang, L.X., Liu, Q., on recrystallization texture and magnetic property of Cu-Ni alloys, Materials Characterization, 121(2016) 149-156. DOI: 10.1016/j.matchar.2016.10.006 [6] Delbove, M., Vogt, J.B., Bouquerel, J., Soreau, T., Primaux, F., Low cycle fatigue behavior of a precipitation hardened Cu-Ni-Si alloy, International Journal of Fatigue, 92 (2016) 313–320. DOI: 10.1016/j.ijfatigue.2016.07.019. [7] Sun, Z., Laitemb, C., Vincen, A., Dynamic embrittlement at intermediate temperature in a Cu–Ni–Si alloy, Materials Science and Engineering, A477 (2008) 145–152. DOI: 10.1016/j.msea.2007.05.013. M A