Research team

Electron microscopy for materials research (EMAT)

Expertise

Materials characterisation by electron microscopy (metals, alloys, catalysts, composites, art & historic materials, ...)

TEM experiments. 15/02/2021 - 14/02/2022

Abstract

This agreement allows Drs. Tong Yang from the Central South University, Changsha, Hunan, China, to join in TEM experiments at the EMAT laboratory of the University of Antwerp, Belgium, on 5 samples provided by Prof. Dr. Yaoxue Zhang and Prof. Dr. Kai Li of the State Key Lab of Powder Metallurgy, Central South University, Changsha, Hunan, China. A systematic method will be established for quantitative characterization of multiscale 3D structure experiments of Al alloys. The samples will be investigated using in-situ nanomechanical testing with the Push-to-Pull Hysitron sample holder in the Osiris and/or Tecnai microscopes and by analytical characterization on Titan instruments. The samples will be produced by FIB or electropolishing at the EMAT laboratory by or with the support of EMAT personnel. The TEM experiments will be conducted by Drs. Tong Yang under supervision and with support of EMAT researchers and staff. Sessions on FIB and TEM instruments will be designated following regular EMAT rules.

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TEM analysis. 01/01/2021 - 31/12/2021

Abstract

The main objective of the TEM characterizations is to elucidate the fundamental micro/nanoscopic mechanisms controlling healing of damages in Aluminum alloys elaborated in UCLouvain. Ex-situ advanced TEM techniques such as aberration corrected TEM, automatic crystallographic orientation and nanostrain mapping in TEM as well as analytical TEM will be used to characterize defects and interfaces while quantified in-situ TEM testing will be performed in order to directly observe the mechanisms under interest inside the microscope. TEM thin foils for the ex-situ and in-situ TEM characterizations will be prepared in EMAT.

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Rheology of earth materials: closing the gap between timescales in the laboratory and in the mantle (TimeMan). 01/03/2019 - 29/02/2024

Abstract

Most large-scale geological process such as plate tectonics or mantle convection involve plastic deformation of rocks. With most recent developments, constraining their rheological properties at natural strain-rates is something we can really achieve in the decade to come. Presently, these reological properties are described with empirical equations which are fitted on macroscopic, average properties, obtained in laboratory experiments performed at human timescales. Their extrapolation to Earth's conditions over several orders of magnitude is highly questionable as demonstrated by recent comparison with surface geophysical observables. Strain rates couple space and time. We cannot expand time, but we can now reduce length scales. By using the new generation of nanomechanical testing machines in transmission electron microscopes, we can have access to elementary deformation mechanisms and, more importantly, we can measure the key physical parameters which control their dynamics. At this scale, we can have access to very slow mechanisms which were previously out of reach. This approach can be complemented by numerical modelling. By using the recent developments in modelling the so-called "rare events", we will be able to model mechanisms in the same timescales as nanomechanical testing. By combining, nanomechanical testing and advanced numerical modelling of elementary processes we will elaborate a new generation of rheological laws, based on the physics of deformation, which will explicitly involve time (i.e. strain rate) and will require no extrapolation to be applied to natural processes. Applied to olivine, the main constituent of the upper mantle, this will provide the first robust, physics-based rheological laws for the lithospheric and asthenospheric mantle to be compared with surface observables and incorporated in geophysical convection models.

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Microstructural investigation of irradiation assisted stress corrosion cracking mechanism based on focused ion beam analysis of tested and industrial specimens. 01/10/2018 - 30/09/2022

Abstract

The main objective is to study the microstructure and morphology of SCC cracks of tested and industrial specimens. The aim of this study is to provide additional experimental results that could help to rationalize existing methodologies used to analyze the failure of internals. Obtained results will be analyzed in the light of the existing threshold methodology as well as on the basis of a recently proposed quasi brittle fracture model assuming an internal oxidation SCC mechanism. In this study an analysis of O-ring samples tested in the constant load experiment will be performed by utilizing the SEM and TEM. We foresee different type of analyses to be carried out: • Analysis of non-fractured irradiated O-rings on stressed and compressed areas to see whether initiation sites are present. • Analysis of the crack statistics at the outer surfaces and fracture surfaces (branching) of fractured O-rings as function of applied stress and test time (both non-irradiated and irradiated samples). • Analysis of irradiation induced defects by TEM • An energy dispersive X-ray (EDS) spectroscopy, combined with both SEM and TEM, of the same tested O-ring specimens used in the study related to cracking statistics. • Analysis of the grain boundaries of the samples by TEM, in particular oxidized grain boundaries at the crack tip. Some of these materials were retrieved from the inside of a nuclear reactor and are considered as unique test material. Out hot cell facilities and associated experimental techniques provide unique environment and possibility to perform proposed study. In addition, recent acquisition of focused ion beam (FIB) experimental setup at SCK.CEN will allow accurate sample extraction from relevant specimen regions, e.g. close to and beyond the crack tip. Microstructural analysis at the crack tip is expected to provide crucial information in order to elucidate the complex mechanism responsible for irradiation assisted stress corrosion cracking (IASCC).

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TEM analyses (Prof. Pascal J. Jacques) 30/08/2019 - 31/08/2020

Abstract

The main objective of the TEM characterizations is to elucidate the fundamental micro/nanoscopic mechanisms controlling the deformation and fracture of bulk and small-sized metals and alloys elaborated in UCL. Ex-situ advanced TEM techniques such as aberration corrected TEM, automatic crystallographic orientation and nanostrain mapping in TEM as well as analytical TEM will be used to characterize defects and interfaces while quantified in-situ nanomechanical TEM testing will be performed in order to directly observe the plasticity mechanisms inside the microscope. TEM thin foils for the ex-situ and in-situ TEM characterizations will be prepared in EMAT.

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TEM analyses (Prof. Aude Simar). 30/08/2019 - 31/08/2020

Abstract

The main objective of the TEM characterizations is to elucidate the fundamental micro/nanoscopic mechanisms controlling healing of damages in Aluminum alloys elaborated in UCLouvain. Ex-situ advanced TEM techniques such as aberration corrected TEM, automatic crystallographic orientation and nanostrain mapping in TEM as well as analytical TEM will be used to characterize defects and interfaces while quantified in-situ TEM testing will be performed in order to directly observe the mechanisms under interest inside the microscope. TEM thin foils for the ex-situ and in-situ TEM characterizations will be prepared in EMAT.

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TEM analyses (Prof. Thomas Pardoen). 27/06/2019 - 27/06/2020

Abstract

The main objective of the TEM characterizations is to elucidate the fundamental micro/nanoscopic mechanisms controlling the deformation and fracture of hybrid nanolaminated thin films provided by UCLouvain. Ex-situ advanced TEM techniques such as aberration corrected TEM, automatic crystallographic orientation and nanostrain mapping in TEM as well as analytical TEM will be used to characterize defects and interfaces while quantified in-situ nanomechanical TEM testing will be performed in order to directly observe the plasticity mechanisms inside the microscope. TEM thin foils for the ex-situ and in-situ TEM characterizations will be prepared in EMAT.

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HR-TEM experiments. 25/03/2019 - 31/03/2019

Abstract

Many of functional materials such as multiferroic oxides and shape memory alloys contain numerous interfaces and domains, playing key roles in their functions. Nevertheless, understanding of relations between the functions and properties of interfaces, including macroscopic morphologies, local atomic configurations, and electromagnetic states, still have been a big challenge due to difficulties in characterization of individual interfaces. In this joint research project, the aim will be to develop a new methodology to evaluate morphology, atomic structure, and electromagnetic properties of interfaces in functional materials by means of integrating electron microscopy techniques of Kyushu University and University of Antwerp.

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TEM experiments on the Tecnai microscope. 01/07/2018 - 31/12/2018

Abstract

This agreement allows Mr. Chao Deng from the Chonqing University, China to join in TEM experiments at the EMAT laboratory of the University of Antwerp, Belgium, on ACOM-TEM making use of the ASTAR & Topspin equipment. In total 5 training sessions of half a day will be offered during a 4 week period (from 21.07.2018 to 22.09.2018), including demonstration sessions, a hands-on session and a session on data treatment. The training will be carried out by trained EMAT personnel at the EMAT laboratory. The TEM experiments will be conducted on the Tecnai microscope and all necessary support will be provided by designated members of the EMAT team. Sessions on TEM instruments will be designated following regular EMAT rules.

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TEM experiments 01/02/2017 - 31/12/2017

Abstract

This project represents a formal research agreement between UAntwerpen and on the other hand the client. UAntwerpen provides the client research results mentioned in the title of the project under the conditions as stipulated in this contract.

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TEM analysis. 01/01/2017 - 31/12/2019

Abstract

This project represents a formal research agreement between UAntwerpen and on the other hand the client. UAntwerpen provides the client research results mentioned in the title of the project under the conditions as stipulated in this contract.

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TEM experiments. 01/10/2016 - 31/12/2017

Abstract

This project represents a formal research agreement between UAntwerpen and on the other hand the client. UAntwerpen provides the client research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Investigation of the influence of thermomechanical treatments on microstructure and mechanical properties of Ti stabilized 15Cr-15Ni austenitic stainless steel. 01/10/2015 - 30/09/2019

Abstract

The titanium stabilized 15Cr-15Ni austenitic stainless steel is considered as clad and wrapper material for several current fast breeder reactor projects. It is also the primary choice for the MYRRHA reactor fuel assembly and a nuclear-grade batch of cladding tubes and bars has recently been produced by Sandvik for SCK•CEN. This project studies the precipitation of fine secondary Ti(C,N) precipitates after thermal ageing of the 15Cr-15Ni clad and bar material at temperatures relevant for service operation and during storage. Besides the control of the heat treatment parameters, it includes the characterization by Transmission Electron Microscopy (TEM) of the amount and density of secondary Ti(C,N) precipitates. Aged specimens reinforced by the dispersion of nanoscale precipitates will then be tested mechanically to investigate the influence of ageing temperature on mechanical properties.

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TEM nano-statistics investigations of structural defects in nanostructured materials under static and dynamic loading. 01/10/2015 - 30/04/2016

Abstract

Nanostructured materials are found in many different forms of advanced materials. The properties of these materials strongly depend on their nanostructural features and dedicated characterization tools providing nanostatistical data are indispensable for further development of these novel materials. This project focuses on the application of an innovative combination of advanced transmission electron microscopy high-throughput nanoquantification with in-situ quantified testing methods to unravel the fundamental processes activated at the micro- and nanoscale. The latter control the nucleation, mobility and interaction of crystal defects and the resulting mechanical and thermo-mechanical properties of these materials. This combination of techniques is absolutely unique in Europe and will for the first time provide true quantified data on different fundamental processes such as crystallization in metallic glasses, martensitic phase transformations in shape memory alloys and nano-plasticity and thermally activated mechanisms in nanocrystalline Nickel. These are just a few examples of the broad variety of exciting investigations that will become possible through the objectives of this proposal. The outcome of this project will trigger the synthesis of nanomaterials with improved properties and the design of nanostructures with novel functionalities.

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Transmission electron microscopy study on the liquid metal corrosion mechanisms of the 1.4970 austenitic stainless fuel cladding for MYRRHA. 15/04/2015 - 14/04/2019

Abstract

This project represents a formal research agreement between UA and on the other hand SCK. UA provides SCK research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Nano consortium of excellence. 01/01/2015 - 31/12/2019

Abstract

The NANO consortium of excellence represents the internationally renowned expertise in nanoscience at the University of Anwerp. It consists of three participating groups that are international leaders in their subfield: EMAT, CMT and PLASMANT. The consortium joins forces towards a uniform communication and collaboration in order to further strengthen the international position of the nanosciences at the University of Antwerp.

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Study of the fundamental mechanisms of nano-plasticity in asdeposited and hydrided nanocrystalline Pd thin films using highthroughput nanostatistical in-situ nanomechanical TEM testing. 01/01/2015 - 31/12/2018

Abstract

The present project focuses on two main objectives: (1) the investigation of elementary defect mechanisms controlling the growth and hydriding of nc Pd films and (2) the investigation of such mechanisms controlling the (thermo-)mechanical properties in as-deposited and hydrided nc Pd films. The research will be conducted by a combination of novel TEM techniques providing highthroughput nanostatistical data with nm resolution meanwhile allowing for in-situ nano/micromechanical testing experiments including in-situ heating and yielding quantified loaddisplacement and stress-strain curves to provide dynamical data on nanoplasticity.

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Influence of nano- and microstructural features and defects in finegrained Ni-Ti on the thermal and mechanical reversibility of the martensitic transformation and the shape memory and superelastic behavior 01/01/2015 - 31/12/2018

Abstract

In recent years scientists have discovered the potential of materials with extremely fine grain sizes. In many cases, reducing the grain size to sub-micron or even nanoscale dimensions indeed improves mechanical and functional properties. In this project we aim to understand the influence of the nano- and microstructure on the mechanical and functional properties such as shape memory effect, superelasticity, recovery stresses, work output, damping properties, strain hardening and ductility of Ni-Ti alloys.

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TopSPIN for TEM nanostatistics. 19/05/2014 - 31/12/2018

Abstract

This project represents a formal research agreement between UA and on the other hand the Hercules Foundation. UA provides the Hercules Foundation research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Physically based modelling and simulation of the mechanical behaviour of metallic thin film systems and fine grained surfaces under cyclic loading conditions (FASS). 01/01/2014 - 31/12/2016

Abstract

In this project we aim at physically based modelling and simulation of the mechanical behaviour of polycrystalline metallic thin film systems and micropillars under cyclic loads.The ultimate goal of the project is to provide physical foundations for computational design of fatigue resistant microstructures by establishing a predictive multiscale modelling framework for the early stages of fatigue failure. This will be of benefit for a vast range of technological applications including the enhancement of fatigue resistance by surface treatment and fatigue of microscale components.

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Mechanical properties and chemical bonding at the interfaces in polymer-based composite materials (InterPoCo). 01/03/2013 - 28/02/2017

Abstract

The main goals of the SB01 project "Mechanical properties and chemical bonding at the interfaces in polymer-based composite materiais" (InterPoCo) within the H-INT-S program are to (i) develop and apply a set of experimental and computational tools for comprehensive structural, compositional and quantitative mechanical characterisation of the interfaces in polymer-based composites at na no- and microscale level, (ii) to measure and predict structural, electronical, compositional, thermodynamica I and mechanical properties of bulk polymers and interfaces in polymer-based composites, (iii) to validate and improve the prediction reliability by emphasizing the interplay between modelling and experimental data obtained using a high-throughput approach and advanced characterisation results and (iv) to provide currently unavailable information on the above aspects to the running and future vertical SIBO programs.

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Research of the modifications of silver nano particles by degradation and conservation treatments of photographs. 01/10/2011 - 30/09/2015

Abstract

Silver present in photographic materials oxidizes, migrates and reduces in the emulsion causing degradation of the image. This PhD project investigates these modifications of silver by means of electron microscopy and compares the degradation process before and after different treatment methods, e.g. local atmospheric plasma cleaning. As a result the most appropriate treatment method for silver oxidation in photographic materials will be suggested after quantitative analyses.

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Magnetic and microstructural study of ferromagnetic shape memory alloys. 15/11/2010 - 14/05/2012

Abstract

The first purpose of this research project is to investigate the micro- and nano-structural features of the martensite twin and magnetic domain structure in Co-Ni-Al alloys and to relate those to the transformation characteristics and mechanical behavior of these materials. The next purpose is to develop advanced Lorentz microscopy techniques at the host laboratory, extending the possible applications of the lab to magnetic materials.

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Internal investigation of zeolite crystals and their guests. 01/01/2010 - 31/12/2013

Abstract

The general objective of the project is to apply the focused ion beam (FIB) technique (UA) to produce zeolite slices of 50 - 100 nm thickness at various locations and with different orientations and to further perform a detailed structural analysis of these slices with High Resolution TEM.

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Three-dimensional characterisation of precipitates in Ni-Ti shape memory alloys by slice-and-view in a FIB-SEM dual-beam microscope. 01/01/2009 - 31/12/2012

Abstract

Ni-Ti based alloys are at present the mostly used materials in shape memory and superelastic components for applications in a wide variety of fields ranging from stents and orthopedic wires in the medical sector over mechanical actuators to various clutching devices. The martensitic transformation from a cubic B2 austenite structure to a monoclinic B19' martensite structure is the basis for this special behavior. Depending on the application different compositions are used, usually around the equiatomic 50-50, although recently a lot of research has been conducted into ternary systems (with additions of Cu, Hf, Zr, Au, Pt, Pd). The starting material receives a specific thermal treatment resulting in the growth of nano- to micron sized precipitates with type, size and distribution depending on temperature, period of the treatment and possible external stress conditions. These precipitates have a concrete influence on the phase transformation behavior and functional conditions of these materials. A proper understanding of their three-dimensional distribution is thus of crucial importance for the further development of this technology, e.g., in the direction of the important higher temperature domain for applications in the context of engines.

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Minimizing the radiation damage in Ni-Ti-based TEM samples prepared by ion milling techniques. 01/10/2008 - 30/06/2009

Abstract

Classical electro-polishing methods have been already for a long time insufficient to produce all TEM samples, but now they do not even suffice for alloys. One then turns to the alternative of ion milling, but this induces a lot of damage to the remaining material. In order to minimize this damage, a dedicated approach has to be made, for which the experience from intentional radiations is certainly a big advantage.

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Optimalization of Focused Ion Deam (FIB) sample preparation for transmission electron microscopy of alloys. 01/01/2008 - 31/12/2011

Abstract

The target of the present project is to optimize and standardize the FIB preparation methods for a specific class of materials, in this case alloys with a large variety of chemical elements and sample shapes and with the aim on quantitative TEM. Also applications for other materials and research themes, such as electron tomography sample preparation and new aperture design, are envisaged.

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Characterisation of sulphide layers on silver-copper alloys and of yellowish films that are formed during atmospheric plasma treatment of tarnished silver 01/01/2008 - 31/12/2009

Abstract

The aim of this project is to understand why yellowish films are formed during plasma cleaning of tarnished silver-copper alloys. The intensity of these films for alloys containing less than 97 w% of silver increases with the amount of copper in the alloy. In order to understand this phenomenon both sulphide layers and yellowish films will be analysed in detail.

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Micro- and Nanostructural Study of High Temperature Shape Memory Alloys. (ESPINOZA R., Chili) 01/10/2007 - 30/09/2008

Abstract

The present project aims to investigate the micro- and atomic structure of the crystal lattices and defects occuring in one particular Ni-Ti alloy system in which Ni is gradually substituted by Pd. A set of alloys ranging from Ti50Ni45Pd5 to Ti5oNi25Pd25 will be prepared by arc melting followed by the necessary homogenization. The transformation temperatures will be determined by differential scanning calorimetry (DSC) and the effect of different heat treatments will be investigated by TEM.

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Physics and stochastics based multilevel mechanisms of materials. 01/01/2007 - 31/12/2011

Abstract

Strength and deformability of polycrystalline metals are determined by phenomena at various length scales. At a scale which we would label "nanoscopic", dislocations are created and pushed forward by the applied stress, achieving plastic deformation at the nano-scale. At the micro-scale, large numbers of moving dislocations interact and organize themselves in complex patterns. Still at higher scales, massive collective behaviour of these dislocations and patterns allow the plastic deformation of entire grains. On their turn they interact with each other finally leading to a certain mechanical response of the material at the macroscopic scale (i.e., the smallest scale at which it can be looked upon as a continuous medium). The response of the material on applied stresses depends on all these phenomena. Events on the various length scales may also cause important changes in the material, such as microstructure, internal damage and mechanical properties (strength and ductility). Note that the role of dislocations can partially be taken over by mechanical twinning or other stress-induced phase transformations. All this has been extensively studies on all these length scales. These studies certainly do have there merits, and have led to important experimental observations and theoretical understanding of the material behaviour at these length scales. However, in recent years it has become strikingly clear the events of each length scale do influence the events on other length scales, and that more significant progress in the understand (and modelling) of the material behaviour may be achieved by studying these relations than by further refining knowledge on each relevant length scale separately. Finally, strong size effects occur when structural dimensions such as for instance film thickness or grain size starts interacting with the dislocation mean free path or the dislocation cell size, revealing a completely new and almost unexplored physics. On first sight, polymer based, fibre reinforced composite materials seem to belong to a quite different world than polycrystalline metals. And yet, much of what has been said above also applies to these materials. Strength and residual deformability depend on the initiation and further development of damage at the micro-scale. Also here the microscopic events have been seriously studied and modelled, but the study of the coupling with the material behaviour at the macroscopic level (called meso-scopic level by experts in composite materials) is still in its infancy. It did not yet lead to satisfactory generic understanding (and modelling) for the case of general multi-axial straining, so the presents applicants believe that important synergy can be achieved doing the research on metals and composite materials in a collaborative way. Much has to be gained from transferring, when physically relevant, methods and models developed in the metal area to the composite polymer area, and vice-versa. The engineering motivation for looking at these phenomena involves the development of higher performance materials, the optimisation of the manufacturing operations, and the improvement of the design and integrity assessment methods for both traditional (transport, energy) and emerging (MeMS, multifunctional active panels) structures.

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Project website

Structural and chemical characterization of materials at the micro- and nanometer scale. 01/01/2005 - 31/12/2014

Abstract

The study of surfaces, interfaces, microscopic and even nanoscopic structures becomes more and more important in the characterization of very diverse materials in metallurgy, microelectronics, optoelectronics, photographic sciences etc. This characterization is mostly carried out using so-called (micro)beam techniques. By interaction of a "primary" beam (electrons, photons, ions), "secondary" signals are generated at the material's surface (electrons, photons, ions, neutrals), which contain information on the composition and/or structure of the material's surface. The various techniques differ in the kind of information, i.e. information depth, depth resolution, possibility to measure depth profiles, lateral resolution, compatibility with certain types of materials (electrical insulator vs. conductor, refractory vs. labile material), destructive or non-destructive character and type of information (elemental, istopic, molecular) It is clear that one method cannot answer all questions. Moreover, the required equipment is very expensive It is not possible for one research group to have in-house all infrastructure, accessories, know-how, know-why, and experienced personnel. Cooperation is therefore a must. The scientific research community aims at facilitating mutual consultations, exchanges and access to complementary equipment for solving a variety of problems, introduced by one or more of its members.

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The functional properties of shape memory alloys : a fundamental approach. 01/01/2005 - 31/12/2008

Abstract

In spite of a long tradition of international research many aspects, especially quantitative ones, of the functional properties of (NiTi- ) shape memory alloys are not explained or understood. The origin of this is probably the fact that the increasing commercial success of those alloys, especially in the medical business, has driven the research to application optimalisation rather than to seek for the fundamental origin of the observations. This became very clear during a recent finished EU-craft and a EU-Growth project in which recovery stresses of constrained elements and wires had to be optimized without explaining why the given treatments gave different results. So, it is evident that the absence of a fundamental understanding of a lot of experimental observations hampers the optimal use of shape memory alloy. Based on those experiences, our international recognition in the field of shape memory alloys and the long term experience with NiTi alloys, a fundamental project is proposed which should lead to the understanding of the mechanical, physical and thermodynamic relationship between microstructure and functional properties, as function of the thermo- mechanical history, the composition and the applied temperatures.

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Multi-scale modelling and characterisation for phase transformations in advanced materials.(MULTIMAT) 01/10/2004 - 30/09/2008

Abstract

Many current problems in advanced functional materials are related to the large range of length and time scales involved in the phase transformations that occur in them. In order to understand the details of the behaviour of such materials and ultimately to put this understanding to use in advanced applications, we need to bridge this multitude of scales by appropriate schemes of interconnected theoretical approaches. The quality and usefulness of these theories have to be tested through comparison with well designed experiments on a series of typical materials, chosen for their relevance to the scientific and engineering communities. The proposed network will address these problems in a highly multidisciplinary way, involving scientists from applied mathematical groups as well as theoretical and experimental solid state physicists. Moreover, the combination of teams forms a geographically representative picture of the relevant research in Europe, including groups from East-Europe, Mediterranean countries and less-favoured regions and is supported by a US team consisting of exceptional researchers. Although recently contacts between these different communities have increased, the variety and complexity of the different approaches still requires special training and transfer of knowledge opportunities for early stage as well as experienced researchers to ensure new and continuing cross-talk between their members. The training and transfer of knowledge will be organised by setting up a scheme of exchange procedures combining in-house training with individual secondments, dedicated courses, schools and workshops. The totality of these exchanges will be overviewed by a training steering committee. The average ratio between early stage and experienced researchers is 48/36 yielding a perfect combination between stability and flexibility. The research is organised into four general objectives. The first combines all characterisation techniques and defines the concrete model systems chosen for the experiments, such as shape memory materials, ferroelectrics and materials with enhanced magnetoresistance. The three others deal with generic theoretical and numerical approaches to phase transformations and related aspects. The identified tasks imply strong collaborations between different teams.

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Multi-scale modelling and characterisation for phase transformations in advanced materials.(MULTIMAT) 01/10/2004 - 30/09/2008

Abstract

Many current problems in advanced functional materials are related to the large range of length and time scales involved in the phase transformations that occur in them. In order to understand the details of the behaviour of such materials and ultimately to put this understanding to use in advanced applications, we need to bridge this multitude of scales by appropriate schemes of interconnected theoretical approaches. The quality and usefulness of these theories have to be tested through comparison with well designed experiments on a series of typical materials, chosen for their relevance to the scientific and engineering communities. The proposed network will address these problems in a highly multidisciplinary way, involving scientists from applied mathematical groups as well as theoretical and experimental solid state physicists. Moreover, the combination of teams forms a geographically representative picture of the relevant research in Europe, including groups from East-Europe, Mediterranean countries and less-favoured regions and is supported by a US team consisting of exceptional researchers. Although recently contacts between these different communities have increased, the variety and complexity of the different approaches still requires special training and transfer of knowledge opportunities for early stage as well as experienced researchers to ensure new and continuing cross-talk between their members. The training and transfer of knowledge will be organised by setting up a scheme of exchange procedures combining in-house training with individual secondments, dedicated courses, schools and workshops. The totality of these exchanges will be overviewed by a training steering committee. The average ratio between early stage and experienced researchers is 48/36 yielding a perfect combination between stability and flexibility. The research is organised into four general objectives. The first combines all characterisation techniques and defines the concrete model systems chosen for the experiments, such as shape memory materials, ferroelectrics and materials with enhanced magnetoresistance. The three others deal with generic theoretical and numerical approaches to phase transformations and related aspects. The identified tasks imply strong collaborations between different teams.

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Weathering of blue and purple enamels: an old problem studied with the newest techniques. 01/02/2004 - 31/12/2005

Abstract

The project aims to study the relation between the chemical composition of blue and purple enamels, of the substrate glass they are applied upon and the wheathering processes these materials are subject to, that are part of historical stained glass windows.

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Focused ion beam (FIB). 01/01/2004 - 31/12/2006

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Organisation 13th European Microscopy Congress. 01/12/2002 - 31/12/2002

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    Ab initio calculations of EELS spectra in Ni- and Ti-based intermetallics. 01/11/2002 - 31/01/2003

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      Multi-scale modelling and characterisation for phase transformations in advanced materials. 01/11/2002 - 31/12/2002

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        Repair FEG CM30 electron microscope. 01/07/2002 - 31/12/2002

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          Visualisation and microstructural characterisation of the subphases in the formation of silver in order to get a clearer insight in the density formation and colour/toning problems. 01/05/2002 - 31/12/2002

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            Characterisation of nanostructures by advanced electron spectroscopy and filtering. 01/01/2002 - 31/12/2005

            Abstract

            This project aims at the optimisation of the methodology of the simultaneous determination of the electronic and atomic structure and the chemical composition and speciation of nano configurations in a single instrument. The required instrumentation is already available at EMAT (Electron Microscopy for Materials Research) within two different electron microscopes, but the optimal registration of the data and the interpretation of the results still require an integrated effort from various research areas. The above-mentioned nano-structural aspects are of utmost importance for the physical and chemical properties of many materials rendering this fundamental research project a gateway to several novel technological applications. The data sets that will be treated will be acquired using two high resolution transmission electron microscopes (HRTEM) (3000F ARP, CM30 UT), equipped with a field emission gun (FEG) and an electron energy loss spectrometer (EELS) with an energy filter (EF) and CCD detector. The first instrument also has a high resolution scanning transmission unit (STEM) and energy dispersive X-ray detector (EDX). Both instruments provide the possibility to work in nanoprobe, by which spectroscopic information of extremely small volumes can be obtained. The emphasis of the present project is on the optimisation of the acquiring and interpretation of EELS results in combination with other techniques. The fine structure of the spectra can give information on the chemical state and environment enabling the so-called speciation of the elements. In order to reach the extreme detail aimed for, the working conditions of both instruments have to be secured to minimise external influences. The possibility to record the information directly in a digital way via different detectors and CCD cameras implies a strongly enhanced and useful quantitative output. To make this project feasible and successful different domains of expertise available at the UA are brought together: HRTEM and EELS detection (EMAT) and interpretation with respect to chemical speciation (MiTAC) for materials science and the research of image and data improvement (Visielab). In the framework of this project three model systems will be investigated with the objective of optimising the performance of the various possibilities of the instrumentation. Apart from the structural characterisation, particular attention will be paid to the EELS methodology from which chemical as well as electronic information can be extracted. As a first system thin films of La1-xSr xMnO3 (CMR : Colossal Magnetic Resistance)-material in which various valency-states of Mn-ions can disintegrate on a nanometer scale will be examined. This demixing can only be visualised by the differences in the fine-structure of the EELS-spectra (ELNES) of the different states. A second system concerns diamond-like carbon films (DLC) produced by plasma enhanced chemical vapour deposition (PE-CVD). In these films one wants to discriminate the different types of carbon bonds depending on the plasma conditions. Again, especially ELNES will provide the necessary information. In the third model system nanoprecipitates in a known silicon or germanium matrix will be characterised. These precipitates are known from high resolution studies in EMAT but the structure and contents could up to now not unambiguously be determined because no chemical information, e.g. on the presence of oxygen, was available at the required nanoscale. Again the nanoprobe EELS-data should supply the required information for a thorough structure analysis including the speciation of the elements. In a later stage of the project the developed methods and acquired know-how will open possibilities for the study of nano-configurations and interfaces in materials which are more complex than the chosen model systems.

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            Replacement CCD camera. 19/12/2001 - 31/12/2001

            Abstract

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              01/01/2001 - 31/12/2001

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                Controlling the physical/chemical properties of organic nanodispersions. 01/11/2000 - 30/04/2002

                Abstract

                Acquiring basic insight aiming at the production and control of properties of organic nanodispersions. Using supramolecular crystal chemistry (e.g. additives) the crystal structure or surface will be changed in order to affect the properties.

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                  01/10/2000 - 31/12/2000

                  Abstract

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                    Defects and surface layers of anisotropic silver halide microcrystals. 01/01/2000 - 31/12/2001

                    Abstract

                    Tabular crystals have superior properties over isotropic crystals as light sensitive element in a photographic film. To produce them defects have to be introduced that induce accelerated growth along certain directions. These defects cause a morphological heterogenisation of the crystal population. With transmission electron microscopy the defects responsible for anisotropic growth will be characterised and their influence on the morphology in order to control the growth process.

                    Researcher(s)

                    • Promotor: Van Landuyt Joseph
                    • Co-promotor: Schryvers Nick
                    • Fellow: Van Renterghem Wouter

                    Research team(s)

                      Valorisation of recently defined configurations for the extraction of band structure data from EELS spectra. 01/01/2000 - 30/11/2000

                      Abstract

                      The changes induced by composition, structure and ordening of materials on the electronic band structure will be investigated using EELS. This will be applied to Ni-based alloys. The technical expertise needed for the registration and interpretation of the spectra will be transferred to other researchers, working on other materials.

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                        Electron microscopic study of precursors and phase transformations in nanoscale intermetallic compounds. 01/04/1999 - 31/03/2000

                        Abstract

                        Precursors of different phase transformations in Ni-based alloys will be investigated by different advanced TEM techniques, including quantitative high resolution and electron energy loss spectroscopy. This way new detailled information on structure, composition and electronic parameters will be obtained.

                        Researcher(s)

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                          Phase transitions in crystalline solids. 01/09/1998 - 28/02/2004

                          Abstract

                          Different aspects of symmetry breaking phase transitions in crystalline materials are investigated by theoretical models which are compared with experimental results.

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                          Structural aspects of phase transformations in two-dimensional materials. 01/01/1998 - 31/12/1999

                          Abstract

                          Effects of non-isotropic dimensions of Ni-based alloys on their phase-transformations are investigated. Especially thin films, melt-spun and splat-cooled Ni-Al alloys are involved.

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                            Development of composite coatings on light metals in order to improve their resistance towards surface damage. 10/12/1997 - 10/03/2001

                            Abstract

                            Development of improved composite coatings from a metallic nickel matrix reinforced by small particles onto light materials such as magnesium alloys. The coatings are prepared by electrolyses.

                            Researcher(s)

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                              Structural research of metallic thin films with martensitic transformations 01/10/1997 - 31/12/1998

                              Abstract

                              The project is situated in the domain of fundamental research on martensitic transformations (MT) in alloys. This transformation is the origin of the shape memory and superelastic characteristics that are currently applied in different instruments. As a result of the structural transformation, different microstructures develop in the product phase. Until now we have only considered bulk material and the present project will allow us to engage into the field of MT in two-dimensional or thin film materials. It is known that the different morphologies have important effects on the MT and hence on potential applications. However, detailed studies on the atomic and microstructures in such films still need to be performed. In the present project the acquisition of a thermal evaporation unit for the production of Ni-Al and other Ni-based films is scheduled.

                              Researcher(s)

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                                Study of the premartensitic and martensitic atomic and micro-structures by means of high resolution electron microscopy (HREM) 01/05/1996 - 30/04/1998

                                Abstract

                                The atomic and micro-structure of alloys which undergo a martensitic phase-transition is studied by means of HREM and related techniques. Considering the present interest for high temperature materials Cu-Zr and Ni-Mn-Ti has been chosen. Fundamental as well as application-directed phenomena are studied.

                                Researcher(s)

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                                  Improvement and application of high resolution electron microscopy techniques to the study of materials. 01/01/1996 - 31/12/1999

                                  Abstract

                                  1) Order-disorder phenomena in metallic alloys - Martensitic transformations; 2) Structure of and defects in ceramic materials; 3) Super-ionconductors; 4) Modulated incommensurable structures; 5) Phase transitions; 6) Characterization of separation surfaces between solid phases.

                                  Researcher(s)

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                                    High resolution electron microscopy of intermetallic phases in the Ni-Al system. 01/05/1993 - 31/07/1993

                                    Abstract

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                                      AgX-Q-Cluster composite crystals. 01/04/1993 - 31/03/1995

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