SAFRAN, France
Tarek Younsi
Biography
Ingineer in metallic material and process at SAFRAN GROUP. I work on some activities in relation with metals fields in both production engineering and Research and Technology including additive manufacturing projects. We work in Safran in maturation research and also engineering for series production. I made my PhD thesis in additive manufacturing field at IMT Mines Albi, France, the subject was oriented on the study of LPBF process microstructure and the incidence on the microstructure and macrostructure of the structure under dynamic loads including fatigue and tribology. The aim of the thesis was the understanding of the relationship between the process, the microstructure and its evolution under cyclic solicitation implying mechanical behavior and plasticity. I am engineer in my basic training followed by master’s degree on mechanics of materials and structures at ENS Paris Saclay. The training was oriented on mechanical calculation of the material and also the relation between microstructure and macrostructure for different loads.
Conferences
Room |
Date |
Hour |
Subject |
|---|---|---|---|
| Room 6 |
25-03-2026 |
5:20 pm – 5:40 pm |
67 Understanding of the competition between fusion defects and surface roughness on the fatigue behavior of Inconel 718 obtained by Laser Powder Bed Fusion |
Conferences Details
67 Understanding of the competition between fusion defects and surface roughness on the fatigue behavior of Inconel 718 obtained by Laser Powder Bed Fusion
Laser Powder Bed Fusion process is used in aeronautical industry to manufacture some mechanical parts. Understanding of the fatigue propertiesis important for those loaded in fatigue mode during service. Among them, roughness level and presence of defects have a direct impact on the fatigue life. It turns out that the defects more internal than external are inherent to the process microstructure, they result from vacation melting or collapses effect. Among the aeronautical materials, we found Inconel 718 which is high resistant material interesting for its properties for aeronautical applications. The aim of this work is tounderstand and analyse the competition between the defect impact and the roughness impact on the fatigue behaviour. To do this several forms, position and sizes of defects are voluntarily created. The competition will be determined by the impact on the fatigue properties and consolidation by fractographies through Scanning Electronic Microscopy analysis. The results show that for machined surface
(Ra=0.8µm), whatever size between T1 size (0.3mm) and T3 size (1mm) and location (in surface or in bulk) of the defect, failure always initiates at this defect. When the surface state is as built (Ra=7µm), the fatigue knock down is only due to the roughness for the internal defects until T3 size (1mm) size. On the contrary, when the defects are external, the fatigue knock down is only due to the defects for the sizes between T2 size (0.6mm) and T3 size (1mm). This is valid in High Cycles Fatigue and Low Cycles Fatigue.
Keywords: Inco 718, LPBF, HCF, LCF, Defects.
