Mécanique

ISMME - Ingénierie des Systèmes, Matériaux, Mécanique, Énergétique

FOREST Samuel

Centre des Matériaux

13/03/2025

Plasticité cristalline, endommagement intergranulaire, oxydation, éléments finis, champs de phase

Crystal plasticity, Lifetime assessment, Strain localization

Pour réduire le poids des avions et améliorer l'efficacité des moteurs, il reste nécessaire d'optimiser les matériaux aéronautiques métalliques. L'une des solutions est de contrôler leur microstructure cristalline pour optimiser leurs propriétés physiques. Cependant, les caractéristiques précises de la microstructure qui conduisent au comportement du matériau, comme la résistance à la fatigue, ne sont pas entièrement comprises à ce stade. L'objectif de cette thèse est d'étudier par simulation numérique l'amorçage et la micro-propagation des fissures de fatigue en tenant compte précisément des caractéristiques de la microstructure. A l'heure actuelle ces propriétés microstructurales ne sont que très peu prises en comptes, conduisant à de fortes imprécisions dans les prévisions comportementales.
En particulier, il s'agit dans cette thèse de développer une méthode de simulation capable de prévoir la durée de vie des matériaux aéronautiques, tels que les superalliages à base de nickel, en utilisant la caractérisation numérique de leur microstructure, incluant des sources de fissuration réelles que sont des joints de grains, des joints de macles et des inclusions.

To reduce aircraft weight and improve engine efficiency, it is still necessary to optimize metallic aeronautical materials. One solution is to control their crystalline microstructure to optimize their physical properties. However, the precise characteristics of the microstructure that drive material behavior, such as fatigue resistance, are not fully understood at this stage. The aim of this thesis is to study the initiation and micro-propagation of fatigue cracks using numerical simulations, taking precise microstructural characteristics into account. At present, very little account is taken of these microstructural properties, leading to considerable inaccuracies in constitutive behavior predictions. In particular, the aim of this thesis is to develop a simulation method capable of predicting the service life of aeronautical materials, such as nickel-based superalloys, using numerical characterization of their microstructure, including real sources of cracking such as grain boundaries, twin boundaries and inclusions.

In 2019, the European Commission presented the European Green Deal. Among others, one of the challenges proposed is the net-zero greenhouse gas emissions by 2050. Consequently, the aerospace industry focuses its efforts mainly on reducing aircraft weight and improving engine efficiency. In the case of new aircraft engine development, increasing in-service temperature and rotation speed are required to improve overall engine efficiency. One possible solution for these requirements is material optimization by using its microstructural design.
Modern simulations of the manufacturing process combined with microstructure information and a microstructure-informed lifetime model could help design the whole manufacturing process and optimize the lifetime allowing more design margins. There have already been some studies about comprehensive microscale analyses for industrial applications. For example, fatigue properties of Ni-based alloys used for turbine disks are characterized with two different grain size distributions.
It is known that the distributions of possible crack initiation sites, such as carbide inclusions and twin boundaries at/beneath surfaces, play an important role in the lifetime of the material. For example, surface defects lead to tremendously shorter lives than internal ones. Moreover, once a crack is initiated, the crack may or may not propagate to the adjacent metallic grains. But those are just observations that give no quantitative information for design. As a response to industrial demands for new materials with optimized microstructures for higher fracture tolerance with lower density, it is proposed to solve a boundary value problem on a representative volume element (RVE). The RVE of the polycrystalline material consists in an aggregate of grains with size, shape, and orientation distributions that are representative, in a statistical sense, of the microstructure considered. Within this framework, the heterogeneous distribution of stresses, strains, and other internal variable microfields are resolved. Then, the calculations allow further analysis of the localized behaviors affected by microscale defects, such as precipitates or grain boundaries. This analysis is very important for fatigue and/or failure predictions because the fatigue crack initiation and propagation are strongly dependent on the localized behavior. In addition, averaging the microscale variables can also provide the macroscopic responses automatically. These macroscopic results based on microscopic effects can be used for developing new fatigue indication parameters (FIPs) that consider microstructural effects.

Directeur de Thèse 1 : Samuel Forest
Co-directeur de Thèse 2 : Henry Proudhon
Co-encadrant 1 : Mathias Lamari
Co-encadrant externe : Hyung-Jun Chang SafranTech

Ingénieur et/ou Master recherche - Bon niveau de culture générale et scientifique. Bon niveau de pratique du français et de l'anglais (niveau B2 ou équivalent minimum). Bonnes capacités d'analyse, de synthèse, d'innovation et de communication. Qualités d'adaptabilité et de créativité. Capacités pédagogiques. Motivation pour l'activité de recherche. Projet professionnel cohérent.

Pré-requis (compétences spécifiques pour cette thèse) :

Mécanique des matériaux, mécanique numérique, viscoplasticité, lois de comportement.

Pour postuler : Envoyer votre dossier à recrutement_these@mat.mines-paristech.fr comportant
• un curriculum vitae détaillé
• une copie de la carte d'identité ou passeport
• une lettre de motivation/projet personnel
• des relevés de notes L3, M1, M2
• 2 lettres de recommandation
• les noms et les coordonnées d'au moins deux personnes pouvant être contactées pour recommandation
• une attestation de niveau d'anglais

Engineer and / or Master of Science - Good level of general and scientific culture. Good level of knowledge of French (B2 level in french is required) and English. (B2 level in english is required) Good analytical, synthesis, innovation and communication skills. Qualities of adaptability and creativity. Teaching skills. Motivation for research activity. Coherent professional project.

Prerequisite (specific skills for this thesis):

Mechanics of materials, computational mechanics, viscoplasticity, constitutive laws

Applicants should supply the following :
• a detailed resume
• a copy of the identity card or passport
• a covering letter explaining the applicant's motivation for the position
• detailed exam results
• two references : the name and contact details of at least two people who could be contacted
• to provide an appreciation of the candidate
• Your notes of M1, M2
• level of English equivalent TOEIC
to be sent to recrutement_these@mat.mines-paristech.fr

[1] Theska, F., Stanojevic, A., Oberwinkler, B., & Primig, S., “Microstructure-property relationships in directly aged Alloy 718 turbine disks”, Materials Science and Engineering: A, 776 (2020), 138967.
[2] Rielli, V. V., Godor, F., Gruber, C., Stanojevic, A., Oberwinkler, B., & Primig, S., “Effects of processing heterogeneities on the micro-to nanostructure strengthening mechanisms of an alloy 718 turbine disk”, Materials & Design, 212 (2021), 110295.
[3] Texier, D., Gómez, A. C., Pierret, S., Franchet, J. M., Pollock, T. M., Villechaise, P., & Cormier, J., “Microstructural features controlling the variability in low-cycle fatigue properties of alloy Inconel 718DA at intermediate temperature”, Metallurgical and Materials Transactions A, 47 (2016), 1096-1109.
[4] R. I. Stephens and H. O. Fuchs, Metal Fatigue in Engineering (2nd ed.), John Wiley & Sons., 2001, 69.
[5] J. E. Shigley, C. R. Mischke and R. G. Budynas, Mechanical Engineering Design (7th ed.), McGraw Hill Higher Education, 2003.
[6] J. C. Stinville, M. A. Charpagne, A. Cervellon, S. Hemery, F. Wang, P. G. Callahan, V. Valle and T. M. Pollock, 'On the origins of fatigue strength in crystalline metallic materials', Science, 377 (2022), 1065-1071.
[7] D. Texier, A. C. Gómez, S. Pierret, J.-M. Franchet, T. M. Pollock, P. Villechaise and J. Cormier, 'Microstructural Features Controlling the Variability in Low-Cycle Fatigue Properties of Alloy Inconel 718DAat Intermediate Temperature', Metallurgical and Materials Transactions A, 47 (2016), 1096–1109.
[8] D. Texier, J.-C. Stinville, M. P. Echlin, S. Pierret, P. Villechaise, T. M. Pollock and J. Cormier, 'Short crack propagation from cracked non-metallic inclusions in a Ni-based polycrystalline superalloy,' Acta Materialia, 165 (2019), 241-258.
[9] D. Texier, J. Cormier, P. Villechaise, J.-C. Stinville, C. J. Torbet, S. Pierret and T. M. Pollock, 'Crack initiation sensitivity of wrought direct aged alloy 718 in the very high cycle fatigue regime: the role of non-metallic inclusions,' Materials Science and Engineering: A, vol. 678 (2016), 122-136.
[10] Damien Texier, Jean-Charles Stinville, Marie-Agathe Charpagne, Zhe Chen, Valery Valle, Patrick Villechaise, Tresa M. Pollock, Jonathan Cormier, 'Role of Non-metallic Inclusions and Twins on the Variability in Fatigue Life in Alloy 718 Nickel Base Superalloy', In: Tin, S., et al. Superalloys 2020. The Minerals, Metals & Materials Series. Springer, Cham.
[11] Harris Farooq, Georges Cailletaud, Samuel Forest, David Ryckelynck, 'Crystal plasticity modeling of the cyclic behavior of polycrystalline aggregates under non-symmetric uniaxial loading: Global and local analyses', International Journal of Plasticity 126 (2020), 102619.
[12] R. Quey, P. Dawson, F. Barbe. Large-scale 3d random polycrystals for the finite element method: generation, meshing and remeshing. Comput. Methods Appl. Mech. Eng., 200 (2011), 1729-1745.
[13] Lionel Gélébart, 'Grain size effects and weakest link theory in 3D crystal plasticity simulations of polycrystals', Comptes Rendus. Physique, Volume 22 (2021), 313-330.
[14] S. Haouala, R. Alizadeh, T.R. Bieler, J. Segurado, J. Llorca, “Effect of slip transmission at grain boundaries in Al bicrystals”, International Journal of Plasticity, Volume 126 (2020), 102600.
[15] H. Maderbacher, B. Oberwinkler, H.-P. Gänser, W. Tana, M. Rollett and M. Stoschka, 'The influence of microstructure and operating temperature on the fatigue endurance of hot forged Inconel 718 components,' Materials Science & Engineering A 585 (2013), 123-131.
[16] C. Doudard, S. Calloch, F. Hild, P. Cugy and A. Galtier, 'Identification of the scatter in high cycle fatigue from temperature measurements,' Comptes Rendus Mécanique, 332(2004), 795-801.
[17] M. D. Sangid, H. J. Maier and H. Sehitoglu, 'The role of grain boundaries on fatigue crack initiation – An energy approach', International Journal of Plasticity, vol. 27(2011), 801-821.
[18] A. Cruzado, S. Lucarini, J. Llorca, J. Segurado, “ Crystal plasticity simulation of the effect of grain size on the fatigue behavior of polycrystalline Inconel 718”, International Journal of Fatigue, Volume 113 (2018), 236-245.
[19] Gustavo M. Castelluccio, David L. McDowell, ' Microstructure and mesh sensitivities of mesoscale surrogate driving force measures for transgranular fatigue cracks in polycrystals', Materials Science and Engineering: A, Volume 639 (2015), 626-639.
[20] Gustavo M. Castelluccio, David L. McDowell, ' Effect of annealing twins on crack initiation under high cycle fatigue conditions', J Mater Sci 48 (2013), 2376–2387.
[21] Y. Guilhem, S. Basseville, F. Curtit, J.-M. Stéphan, G. Cailletaud, Numerical investigations of the free surface effect in three-dimensional polycrystalline aggregates, Computational Materials Science, vol. 70, pp. 150-162, 2013, doi:10.1016/j.commatsci.2012.11.052
[22] D. Colas, E. Finot, S. Flouriot, S. Forest, M. Mazière and T. Paris, Local Ratcheting Phenomena in the Cyclic Behavior of Polycrystalline Tantalum, JOM Journal of the Minerals, Metals \& Materials Society, vol. 71, pp. 2586-2599, 2019. doi:10.1007/s11837-019-03539-z
[23] D. Colas, E. Finot, S. Flouriot, S. Forest, M. Mazière and T. Paris, Experimental and Computational Approach to Fatigue Behavior of Polycrystalline Tantalum, Metals, vol. 11, article no. 416, 2021. doi:10.3390/met11030416
[24] A. Marano, L. Gélébart and S. Forest, Intragranular localization induced by softening crystal plasticity: Analysis of slip and kink bands localization modes from high resolution FFT-simulations results, Acta Materialia, vol. 15, pp. 262-275, 2019. 10.1016/j.actamat.2019.06.010
[25] A. Marano, L. Gélébart, S. Forest, FFT-based simulations of slip and kink bands formation in 3D polycrystals: influence of strain gradient crystal plasticity , Journal of the Mechanics and Physics of Solids, vol. 149, 104295, 2021. doi.org/10.1016/j.jmps.2021.104295
[26] A. Marano and L. Gélébart, Non-linear composite voxels for FFT-based explicit modeling of slip bands: Application to basal channeling in irradiated Zr alloys, International Journal of Solids and Structures, vol. 198, pp. 110-125, 2020.
[27] J. Wijnen, R.H.J. Peerlings, J.P.M. Hoefnagels, M.G.D. Geers, A discrete slip plane model for simulating heterogeneous plastic deformation in single crystals, International Journal of Solids and Structures, Volume 228, pp. 111094, 2021. doi.org/10.1016/j.ijsolstr.2021.111094.
[28] M. Lamari, P. Kerfriden, O. U. Salman, V. Yastrebov, K. Ammar and S. Forest, A time-discontinuous elasto-plasticity formalism to simulate instantaneous plastic flow bursts, International Journal of Solids and Structures, under revision, 2024.
[29] Manon Lenglet, Modèle d'endommagement de fatigue en lien avec la microstructure dans un alliage d'aluminium, PhD thesis, École des mines, 2024.
[30] Marie Bouyx, Vincent Chiaruttini, Aurélien Vattré, Vincent Bonnand, and Antoine Blanche, Modélisation numérique d'essais en fatigue pour l'étude de la propagation de fissures courtes à partir d'un défaut surfacique, Journées de Printemps, ONERA, 2023.

Concours pour un contrat doctoral

https://www.adum.fr/script/downloadfile.pl?type=78&ID=60642