PhD students
Mariia Arseenko graduated as an engineer majoring in nanomaterials at Belgorod National State University (Russia) in 2013. Now, she is performing a PhD thesis under the supervision of Pr. Aude Simar at Université catholique de Louvain (Belgium). Her research is part of the ERC Starting Grant ALUFIX and focuses on healing of damage in Al alloys with help of healing agents involving eutectic particles. Friction stir processing (FSP) will be used to provide fine distribution of healing particles in the Al matrix. The experimental part on the work includes choosing the best healing material and FSP parameters by help of microstructure and mechanical properties characterization as well as the identification of the damage mechanisms involved.
Laurine Choisez is studying the damage mechanisms, the toughness and the strain-hardening of a beta-metastable family of titanium alloys. TRIP (TRansformation Induced Plasticity) and TWIP (TWinning induced plasticity) effects are simultaneously activated in these alloys, inducing an outstanding work hardening rate. Her research is focusing on the synergy between the prevailing plasticity mechanisms and the ductility of the alloys, the term ductility encompassing here damage resistance and toughness. The post-necking deformation properties and the associated plasticity mechanisms are examined. This thesis aims to characterize and optimize the microstructure evolution, strain-hardening, damage resistance and toughness of a beta-metastable family of titanium alloys.
Olivier Hubert graduated as a materials science engineer at Université catholique de Louvain (Belgium) in 2014 and began a PhD thesis in September 2014 under the supervisation of Prof. Pascal Jacques. In the automotive sector, the latest developments led to the era of third generation steels, exhibiting levels of strength up to 1200MPa, while keeping an adequate ductility. However, this new generation of steels is potentially sensitive to hydrogen embrittlement. Even though hydrogen embrittlement is studied for over 50 years now, it only starts to become an issue in the case of low alloy steels that start to reach problematic levels of strength.
The research work of Olivier, in collaboration with CRM Group (Liège), is to investigate the role and the impact of the diffusible hydrogen on the mechanical behavior of third generation steels presenting a martensitic and/or bainitic matrix together with retained austenite exhibiting a Transformation-Induced Plasticity (TRIP) effect. In order to generate such microstructures, a heat treatment called "Quenching and Partitioning (Q&P)" is carried out in hydrogen-rich atmospheres. More specifically, the role of each phase on the hydrogen capture and/or diffusivity, as well as the influence of other microstructural parameters such as grain boundaries is studied. Single phase martensitic and bainitic microstructures exhibiting different strength levels were processed. The influence of diffusible hydrogen in each microstructure is then studied either after cathodic hydrogen charging or in the case of gaseous hydrogen charging during the annealing process.
Karim Ismail graduated as a materials science engineer at Université catholique de Louvain (Belgium) in 2014 and began a PhD thesis in September 2014 under the joint supervision of Prof. Pascal J. Jacques and Prof. Thomas Pardoen from UCL.
The research work, in collaboration with company ArcelorMittal, is about the characterization and the modeling of the plasticity, the damage and the crack propagation resistance of Dual-Phase steels and third generation steels. A minimum level of fracture toughness is required in the automotive industry to prevent the propagation during forming operations of small edge damage or cracked zones induced by cutting. Therefore, unravelling the relationship between fracture toughness, microstructure and damage mechanisms is essential to develop advanced steels with superior forming ability. Furthermore, reaching superior fracture toughness could open to other potential applications.
Experimental works as well as computational modelling are used to study the behaviour of such steels. A model for the plastic behaviour and for the damage mechanisms related to the microstructure has been developed as a first step towards the modelling of the fracture toughness. A finite element based unit cell approach is used to address the plastic behaviour with a particular focus on the effect of microstructure morphology, as well as of martensite volume fraction and of carbon content. The data extracted from the elastoplastic analysis are fed into a cellular automaton approach of the damage evolution. This model introduces a statistical description of the material while using relatively simple damage evolution laws.
Matthieu Lezaack graduated as a mechanical science engineer at Université catholique de Louvain (Belgium) in 2017. He currently performs a PhD thesis under the supervision of Pr. Aude Simar. His research focuses on friction stir processing (FSP) performed on 7xxx aluminium alloys. FSP could enhance mechanical properties such as fatigue, toughness and crack opening resistance without losing significant strength. Based on the microstructure analysis of 7xxx aluminium series and post processing heat treatments, FSP seems to supress conventional forming process drawbacks in particular precipitates free zones (PFZ) generally observed in industrial alloys. These PFZ are weak zones acting as preferential path to failure. In addition, FSP is expected to be an efficient way to restore the microstructural homogeneity of the alloy.
Mélodie Mandy graduated as a materials science engineer at Université Catholique de Louvain (Belgium) in 2014. Since then, she is doing a PhD thesis under the supervision of Prof. Pascal Jacques. Her project, in partnership with the CRM group in Liège, focuses on the interaction mechanisms between atmosphere and a specific coated steel during the hot stamping process. Used in the automotive industry, this process ensures the steel to provide a high strength while allowing an easy shaping. During those high temperature operations, small amounts of hydrogen can be absorbed by the material and embrittle it. Currently, hydrogen embrittlement becomes a major issue as hydrogen susceptibility increases with steel strength. In this context, her work consists in doing heat treatments under controlled atmospheres and in measuring the related hydrogen amount. Afterwards, materials and atmospheres are also characterized.
Alvise Miotti Bettanini holds a master of science degree from the Royal Institute of Technology (KTH) of Stockholm, where he graduated in 2014. He’s currently a PhD student at IMAP under the joint supervision of Prof. Pascal J. Jacques and Prof. Laurent Delannay. His project, in partnership with Aperam Stainless Steel Europe, contributes to the development of the first ever high strength stainless steel for automotive structural applications. The main efforts deal with the understanding of the Process-Structure-Property relationship to enable the systematic material design of the alloy. Firstly, the critical microstructure features leading to ductile damage nucleation and evolution are identified with Finite Element simulations and Scanning Electron Microscopy of damaged samples. Next, heat treatments are designed in order to produce microstructures with enhanced properties, leading to an increase of the overall performances of the material.
Wei Ren completed his master studies at China University of Petroleum-Beijing holding a degree in Safety Science and Engineering in 2017. He is performing a PhD thesis under the supervision of Prof. Thomas Pardoen at present. The research work, in collaboration with SCK·CEN (Belgium), is about the radiation damage modeling of reactor pressure vessel materials in the ductile upper shelf regime (From Charpy impact upper shelf energy to crack resistance curve). All current regulatory assessment procedures of reactor pressure vessel (RPV) rely essentially on the Charpy impact test, in particular the two parameters characterizing the ductile-to-brittle transition temperature (DBTT) and the upper shelf energy (USE). Such parameters are derived from the surveillance programs aiming at monitoring the vessel materials ageing and embrittlement under irradiation. Contrary to the upper shelf energy concept which is rather rudimentary, the crack resistance curve including initiation toughness and tearing resistance relies on fracture mechanics.
The research combines an experimental part aiming to collect and classify all available data on irradiation effects on the RPV materials properties with an analytical part consisting in physical understanding of the underlying mechanisms of both radiation damage and ductile fracture. It is of prime importance to understand how irradiation modifies the microstructure (nano-size irradiation defects) and this translates into the changes of the crack resistance properties.
Juan Guillermo Santos Macías is doing a PhD thesis under the joint supervision of Pr. Pascal Jacques and Pr. Aude Simar. This project aims at improving the mechanical behaviour of additive manufactured parts through a friction stir processing (FSP) surface mechanical treatment. This post-processing method significantly enhance ductility and is expected to also enhance fatigue resistance. Fatigue is a critical phenomenon in many applications, e.g. structural parts in the aerospace industry. More specifically, this research is focused on studying the effect of FSP on the microstructure (porosity and second phase size and spatial distribution) and mechanical behaviour (residual stresses and fatigue) of selective laser melting AlSi10Mg parts. Furthermore, in order to define an adequate FSP patterning strategy, the project will also feature an analysis of the influence of processing parameters through a chained thermal and microstructural model.
Chao Yin completed his master degree in nuclear engineering and materials science from University of California at Berkeley (U.S.A., 2016) and National Taipei University of Technology (Taiwan, 2013), respectively. He currently performs a PhD thesis under the joint supervision of Prof. Thomas Pardoen and Prof. Roumen Petrov (UGent). His project is in partnership with Belgium Nuclear Research Center (SCK•CEN), and contributes to the development and qualification of irradiation tolerant tungsten and novel toughness-enhanced composites for fusion applications. Tungsten selected as the first wall armor and Tungsten-based composites for structural applications in DEMO are expected to receive doses up to 20 dpa (Fe) (for the EARLY DEMO) or even higher (full power DEMO). Under these conditions, the mechanical properties of the materials are known to degrade radically due to (i) neutron irradiation, (ii) heat transients, (iii) plasma gas uptake and (iv) nuclear transmutation. This research aims at investigation of the radiation damage and post-irradiation mechanical-thermal behavior of tungsten. This will include the experimental study of the novel and baseline grades with respect to tolerance to the neutron damage, and complementary computational assessment.
Senior scientists / postdoctoral researchers
Marie-Stéphane Colla, Dr, Senior scientist - Fracture of steels
Marie-Stéphane Colla graduated in chemical and materials science engineering at the Université catholique de Louvain in 2009 (Belgium). Then, under the supervision of Prof. Thomas Pardoen (iMMC) and Prof. Jean-Pierre Raskin (ICTEAM), she accomplished a PhD on the study of the mechanical properties of thin films, more specifically on the plasticity and creep of freestanding nanocrystalline Pd films. The lab-on-chip technique developed previously at the UCL was adapted to deform Pd thin films. After the PhD, she worked for more than two years at the CRM Group in Liège on the development of industrially viable thin film solar cells on steel. Since June 2016, she is back at the UCL as a research engineer involved in projects dealing with the understanding of fracture behaviour of high strength steels under a wide range of strain rates.
Lipeng Ding, Dr, Postdoctoral researcher
Lipeng Ding obtained his PhD degree (2017) at Chongqing University, P.P. China. His PhD work mainly addressed the precipitation hardening of Al-Mg-Si-Cu alloys by aberration-corrected transmission electron microscopy (TEM). He is now working as a post-doc fellow with Profs. H. Idrissi, A. Simar, P. Jacques in IMAP, Université catholique de Louvain and Prof. Nick Schryvers in EMAT, University of Antwerp. His research mainly focuses on unraveling defects behaviour of novel metallic and metallic-based materials, such as high-entropy alloys, Ti-Mo alloys and aluminium based alloys using quantitative advanced TEM techniques such as aberration corrected TEM, orientation and nanostrain mapping in TEM and in-situ TEM nanomechanical testing.
Valentin Marchal-Marchant, Dr, Senior scientist - Thermoelectric Materials Development
Valentin Marchal-Marchant obtained his degree in engineering in materials science from the Université catholique de Louvain in 2011. Then, he accomplished his PhD under the supervision of prof. Pascal Jacques, on the study of Physical Vapor Deposition of thick copper films on steel.
His research is now focused on the development of thermoelectric materials and thermoelectric generators for energy harvesting and passive electromechanical systems. It aims at using common and non-toxic materials to generate electrical power from thermal gradients. Nowadays, attention is put on large scale applications owing to more than 7 years of research about thermoelectric materials leaded in IMAP.
The big challenge of this topic is the development of new tools and equipments for material production and assembly, and specific characterization methods. Such a wide range of different tasks can only be achieved thanks to the versatility of technical and scientific expertises of the IMAP team members as well as Lacami support.
Matthieu Marteleur, Dr, Senior scientist - Frature of steels and xxx
Geoffrey Roy, Dr, Senior scientist
Geoffrey Roy holds a Master in Mechatronic Engineering (2010) and a PhD in Engineering (2015) from the Université catholique de Louvain where he works as a senior researcher at the Institute of Mechanics, Materials and Civil Engineering (iMMC).
Within the Division of Materials and Process Engineering (IMAP), his research is focused on the development of new thermoelectric materials and systems for a range of applications going from industrial waste heat recovery to autonomous powering of smart sensors. In his research, he pays particular attention to the development of new solutions that present improved both technical and economical profiles in order to facilitate the emergence of these solutions out of the lab.
This research is followed by several companies such as: Drever International, AGC Glass Europe, Carmeuse or Engie.
Sophie Ryelandt, Senior scientist - High performance metallic alloys
Sophie Ryelandt graduated as a physical engineer at Université catholique de Louvain in 1991. After having worked for six years at the R&D center of the Spadel company, she came back at UCL as a senior scientist. She is involved in various applied research projects in collaboration with the industry. Her research domains are dealing with material science, metallic composites, multilayered materials and coatings, additive manufacturing of metals, nanomechanical and mechanical testing and the link between microstructure and mechanical properties.
Camille van der Rest, Dr, Senior scientist - High performance metallic alloys
Camille van der Rest completed her PhD thesis on the optimisation of Heusler Fe2VAl-based thermoelectric compounds through innovative metallurgical processing in 2015. It was under the joint supervision of Prof. Pascal Jacques and Prof. Aude Simar. Her research topics now concern thermoelectric materials, additive manufacturing and friction stir processing technologies. Concerning thermoelectrics, the main objective is the development of low-cost, non-toxic, and powerful materials that could be used in large-scale industrial applications of heat recovery. In addition, she studies some fundamental aspects in order to improve the performances of such materials, i.e. ordering phenomena in off-stoichiometric Fe2VAl-based Heusler compounds. It is essential to make the link between (innovative) manufacturing processes, microstructures and the functional properties of these TE materials. Concerning additive manufacturing, the main contributions are on the characterisation and optimisation of the microstructures and the mechanical behaviour of Al parts obtained by Selective Laser Melting and the developpment of new materials for additive manufacturing. Again, the link between the process parameters and the final microstructure/properties is a key issue. Finally, Camille developed, together with Prof. Aude Simar and Prof. Pascal Jacques, a novel Friction Melt Bonding (FMB) process in order to weld aluminium alloys and steels. This process is still under development thanks to the collaboration with other researchers of IMAP.
Lv Zhao, Dr, Postdoctoral researcher
Lv ZHAO completed his Master and PhD degrees in Institut National des Sciences Appliquées de Lyon in 2013 and 2016. His PhD work addressed the fracture behavior of solar grade monocrystalline and multi-crystalline silicon wafers, in which a couple of innovative experimental techniques have been elaborated and new results highlighted. He is now working for the ERC Starting Grant ALUFIX as a post-doc fellow with Professor Aude Simar. He is particularly interested in the crack propagation in aluminum alloys in the presence of local residual stresses induced by healing agents such as shape memory alloy particles. His work encompasses an experimental part in which metal matrix composites (MMCs) will be fabricated by friction stir processing, and a numerical part in which cohesive zone method will be applied to address the crack path within the MMCs in the framework of finite element modeling.
Alumni
Florent Hannard graduated as a materials science engineer at Université catholique de Louvain (Belgium) in 2013. He did a PhD thesis (funded by a FRIA grant), started in September 2013 and under the joint supervision of Prof. Thomas Pardoen and Prof. Aude Simar from UCL. His research focused on the contribution from microstructure heterogeneities on the micromechanisms of ductile damage and cracking in metallic alloys. In order to address these effects on damage accumulation, a combined experimental and a modeling strategy was developed. The experimental strategy relied on in situ tensile testing coupled to 3D microtomography, in situ laminography during sheet loading and a variety of more classical mechanical tests. A cellular automaton type modeling was used to capture particle size distribution and cluster effects on the void nucleation and coalescence processes. His project also involved the use of friction stir processing (FSP) in order to increase the ductility of industrial aluminium alloys of the 6xxx series. From an applicability viewpoint, this method had the potential to locally improve ductility of sheets at locations where forming involved large strains or of structural components at stress concentration points.
Zhiping Xiong, Dr, Senior scientist
Zhiping XIONG obtained Ph.D degree (2017) at the University of Wollongong, Australia following the completion of Bachelor degree (2009) and Master degree (2012) at the University of Science and Technology Beijing, P.R. China. He also worked as an assistant engineer (2012-2013) in CISDI Engineering Co., Ltd. P.R. China, involving in the on-site and off-site designs of pickling line, cold rolling, continuous annealing line and continuous galvanizing line.
His main research interests are in the processing-microstructure-property relationship in steels (such as dual phase steel, transformation-induced plasticity steel and twinning-induced plasticity steel) subjected to thermo-mechanical processing and impact loading. The multi-scale microstructures are characterized using advanced techniques such as scanning and transmission electron microscope, electron backscattering diffraction and atom probe tomography.
He worked as a postdoc under the supervision of Prof. Pascal Jacques at the Institute of Mechanics, Materials and Civil Engineering in the Université catholique de Louvain, Belgium. His research, in collaboration with ArcelorMittal, focused on the fracture mechanism of third advanced high strength steels (quenching & partitioning steel and carbide-free bainitic steel) evaluated using double-edge-notched tension.