Le contexte de cette thèse couvre les dispositifs photoniques hybrides III-V sur silicium. L’étude porte sur l’intégration par collage de matériau à base d'InP sur le silicium, puis la conception d’un guide optique comportant une nanostructuration qui permettra la sélection en longueur d’onde dans un laser DFB hybride. Enfin, on étudie les étapes technologiques de fabrication d’un laser hybride injecté électriquement fonctionnant dans le domaine spectral 1.55µm, et on caractérise les dispositifs. Pour associer les matériaux III-V sur Si, nous avons développé le collage sans couche intermédiaire que l’on nomme collage hétéroépitaxial ou oxide-free. Ce collage est reporté dans la littérature comme présentant une meilleure qualité électrique. Nous avons établi les conditions de préparation permettant d’obtenir des surfaces parfaitement désoxydées, et les conditions de recuit conduisant à une interface hybride sans oxyde et sans dislocation. Mais ce recuit est réalisé à température assez élevée (~450-500°C). Nous avons alors développé le collage avec une fine couche intermédiaire d’oxyde réalisé à plus faible température -300°C- qui présente l'avantage d'être compatible avec la technologie CMOS. Nous avons étudié différentes approches pour élaborer et activer une couche d’oxyde très fine (~3nm), de façon à obtenir une surface collée sans zones localement non collées. Le collage est dans les deux cas réalisé sous vide dans un équipement de type Bonder Suss SB6e. La qualité structurale de l’interface a été observée par STEM et la qualité mécanique du joint de collage a été caractérisée par indentation. Une méthode originale de mesure quantitative et locale de l’énergie du joint de collage a été développée. La qualité optique des couches collées a été étudiée par la mesure de la photoluminescence de puits quantiques placés proches du joint d’interface. En conséquence du collage sans couche intermédiaire ou avec une couche très fine, le design du mode optique est de type double-cœur, qui ne nécessite pas de taper. Le guide optique Si est de type shallow ridge, le confinement latéral étant assuré par un matériau nanostructuré à une période sub-longueur d’onde. Ce matériau fonctionne comme un matériau effectif uniaxe pour lequel on a calculé les indices optiques ordinaire et extraordinaire selon la géométrie de la nanostructuration. On peut rajouter sur cette nanostructuration une super-périodicité qui conduit à un fonctionnement sélectif en longueur d’onde. Le comportement modal du guide est simulé à l'aide du logiciel COMSOL Multiphysics, le comportement spectral est simulé par FTDT 3D. Nous avons validé la pertinence de ce design en mesurant la transmission de guides hybrides. Ce design sera inclus dans un laser et permettra d’obtenir une émission monofréquence de type DFB. Nous avons développé les étapes technologiques nécessaires à la fabrication d’un laser hybride à base d'InP sur Silicium fonctionnant en injection électrique. Nous avons mis en oeuvre de nombreuses techniques, et développé plusieurs procédés spécifiques, en particulier, des procédés de gravure sèche de type Inductive Coupled Plasma Reactive Ion Etching ICP-RIE pour la gravure de la nanostructuration dans le silicium, et pour la gravure du mésa du laser. La présence des 2 matériaux III-V et Si dans le dispositif hybride rend ces étapes complexes. Les premiers résultats peuvent être améliorés en optimisant la technologie des contacts. Un design permettant de s’affranchir de la pénalité thermique présenté par tous les dispositifs ayant les 2 contacts électriques du coté du matériau III-V a été proposé, exploitant le passage du courant à l’interface hybride III-V / Si, ce qui est possible dans le cas du collage oxide-free. Cette approche ouvre des perspectives d’intégration au-delà de la photonique. / This work contributes to the general context of III-V materials on Silicon hybrid devices for optical integrated functions, mainly emission/amplification at 1.55µm. Devices are considered for operation under electrical injection, reaching performances relevant for data transfer application. The main three contributions of this work concern: (i) bonding InP-based materials on Si, (ii) nanostructuration of the Si guiding layer for spatial and spectral control of the guided mode and (iii) technology of an hybrid electrically injected laser, with a special attention to the thermal budget. Bonding has been investigated following two approaches. The first one we call heterohepitaxial or oxide-free bonding, is performed without any intermediate layer at a temperature ~450°C. This approach has the great advantage allowing electrical transport across the interface, as reported in the literature. We have developed oxide-free surface preparation for both materials, mainly InP-based layers, and established bonding parameter processing. An in-depth STEM and RX structural characterization has demonstrated an oxide-free reconstructed interface without any dislocation except on one or two atomic layers which accommodate the large lattice mismatch (8.1%) between InP and Si. Photoluminescence of quantum wells intentionally grown close to the interface has shown no degradation. We have also developed an oxide-based bonding process operated at 300°C in order to be compatible with CMOS processing. The original ozone activation of the very thin (~5nm) oxide layer we have proposed demonstrates a bonding surface without any unbonded area due to degassing under annealing. We have developed an original method based on nanoindentation characterization in order to obtain a quantitative and local value of the surface bonding energy. Related to the absence or to the very thin intermediate layer between the two materials, our modal design is based on a double core structure, where most of the optical mode is confined in the Si guiding layer, and no taper is required. The Si waveguide on top of the SOI stack is a shallow ridge. A nanostructured material on both sides of the waveguide core ensures the lateral confinement, the nanostructuration geometry being at a sub-wavelength period in order to operate this material well below its photonic gap. It behaves as an uniaxial material with ordinary and extraordinary indices calculated according to the structuration geometry. Such a structuration allows modal and spectral control of the guided mode. 3D modal and spectral simulation have been performed. We have demonstrated, on a double-period structuration, a wavelength selective operation of hybrid optical waveguides. Such a double-period geometry could be included in a laser design for DFB operation. This nanostructuration has larger potential application such as coupled waveguides arrays or selective resonators. We have developed all the technological processing steps for an electrically injected hybrid laser fabrication. Main developments concern dry etching, performed with the Inductive Coupled Plasma Reactive Ion Etching ICP-RIE technique of both the nanostructuration of the Silicon material, and the mesa of the hybrid laser. Efficient electrical contacts fabrication is also a complex step. First lasers operating performances could be improved. We have investigated a specific design in order to overcome the thermal penalty encountered by all the hybrid devices. This penalty is due to the thick buried oxide layer of the SOI stack that prevents heating related to the current flow to be dissipated. Taking advantage of the electrical transport we have shown at the oxide-free interface, we propose a design where the n-contact is defined on the guiding Si layer, suppressing thermal heating under electrical operation. Such an approach is very promising for densely packed hybrid devices integrated with associated electronic driving elements on Si.

This thesis was most concerned with the mechanical response to irradiation of two in-house produced oxide dispersion strengthened (ODS) steels and two non-ODS coun- terparts. The steels, manufactured by Dr. M. J. Gorley (University of Oxford), were me- chanically alloyed from gas-atomised Fe-14Cr-3W-0.2Ti, with the addition of 0.25Y₂O₃ powder in the case of the ODS variants. The powders were hot isostatic pressed at consolidation temperatures of 950 °C and 1150 °C. The four steels were designated 14WT 950 (non-ODS), 14YWT 950 (ODS), 14WT 1150 (non-ODS) and 14YWT 1150 (ODS), and were used in the as-produced condition. Initially, the macroscale elastic modulus and yield stress were determined using a four-point flexure test, employing digital image correlation (DIC) as a strain gauge. The microcantilever size eects were then characterised, and it was determined that the yield stress signicantly diverged from macroscale values at microcantilever beam depths of < 4.5 μm. Using knowledge of this, the in-house produced alloys were irradiated with 2 MeV protons at the Surrey Ion Beam Centre (University of Surrey, UK) to a displacement damage of ∼ 0.02 dpa and 0.2 dpa (Bragg peak). This was to produce a deep irradiated layer for the fabrication of large microcantilevers with reduced size effects. The cross-sectional surface of the irradiated layer was then exposed and inclined linear arrays of 250 nm deep indents were placed across the damage prole. 14WT 1150 (non-ODS) revealed a clear proton damage prole in plots of hardness against irradiation depth, 14WT 950 (non-ODS) also showed modest hardening in the region of the Bragg peak. No appreciable hardening was observed in either 14YWT specimens, attributed to the fine dispersion of nanoscale oxides providing a high number density of defect sink sites. However, a large bimodal variation in hardness was measured in both ODS variants. This was investigated using EBSD and EDX, and was determined to be caused by a pronounced heterogeneity of the microstructure. While Hall-Petch strengthening and changes in the local chemistry had some effect on the measured hardness, the most likely cause of the large variation in local hardness was heterogeneity in the nanoscale oxide population. Microcantilevers were fabricated out of the irradiated layer cross-section in 14WT 1150 and 14YWT 1150. Larger microcantilevers, with ∼ 5 μm beam depth, were placed with their beam centre at ∼ 0.026 dpa. Smaller microcantilevers, with ∼ 1.5 μm beam depth, were placed with their beam centre at the Bragg peak, 0.2 dpa. Both the large and the small microcantilevers fabricated in 14WT 1150 (non-ODS) displayed significant irradiation hardening. In the ODS variant, 14YWT 1150, irradiation hardening appeared to be reduced. The work in this thesis successfully showed that it was possible to extract a close approximation of the macroscale yield stress from shallow irradiated layers, providing that the irradiation condition is carefully chosen in response to known size dependent behaviour. This thesis also investigated the size dependent behaviour of microcantilevers using a lengthscale dependent crystal plasticity UMAT, developed by Dunne et al. and implemented within ABAQUS 6.14-2 commercially available nite element software. The simulation of the GND density evolution with increasing plastic strain allowed their contribution to the microcantilever size effect, through mobile dislocation pinning, to be determined. This novel approach to modelling size effects in three dimensional finite element microcantilever models demonstrated that while it was possible to simulate a lengthscale-dependent response in finite element microcantilever models, the constitutive equation for the plastic velocity gradient needs to be more physically based in order the match the experimentally derived results; for example, a lengthscale-dependent term relating to the dislocation source density of the material. Although the apparent reduction of irradiation hardening in ODS in-house produced alloys showed great promise, these alloys also displayed a large amount of scatter in measured hardness and yield stress, attributed to the pronounced heterogeneity in the microstructure. Alloys with such signicant microstructural heterogeneity are not suitable for engineering or commercial use.

Les aciers inoxydables austénitiques métastables sont le siège de différents mécanismes de déformation qui sont à l'origine des propriétés mécaniques qui distinguent ce type d’alliages. Cependant, ces dernières, dépendant de la microstructure locale, sont fortement anisotropes. Par ailleurs, la déformation d'un échantillon massif serait différente de celle obtenue en surface. De ce fait, une étude détaillée trouve tout son intérêt. Le présent travail vise donc à identifier les principaux mécanismes de déformation et de leur évolution progressive, en se basant sur une déformation contrôlée de grains austénitiques individuels par des tests mécaniques de nanoindentation monotoniques et cycliques. Les courbes correspondantes au chargement-déchargement révèlent des informations détaillées sur les propriétés mécaniques sous-jacentes qui pourraient être liées à une étude complète de la structure de déformation en surface et en volume par différentes techniques de caractérisation à une échelle très fine. La déformation en fonction du temps, les phénomènes de transformation de phase réversible sous charge, l'anisotropie cristalline, l'influences de la taille des grains, la transmission de la plasticité et la tenue en fatigue ont été mis en évidence et étudiés / Metastable austenitic stainless steels feature an abundance of different deformation mechanisms, which contribute to the distinguished mechanical properties of these alloys. However, these properties are known to depend on the local microstructure and also are highly anisotropic. Furthermore, deformation is expected to be different for the bulk and the surface of a sample. In this sense, a discrete study is not trivial. The present work aims at investigation of the main deformation mechanisms and their gradual evolution, by employing controlled deformation of individual austenite grains via monotonic and cyclic nanoindentation. The corresponding loading–unloading curves have given extensive information about underlying mechanical properties, which could be related to an exhaustive reconstruction of the deformation substructure, both in surface and bulk, by different small scale characterization techniques. Amongst others, features such as time-dependent deformation, reversible phase transformation under load, crystalline anisotropy and grain size influences, besides plasticity transmission and fatigue behavior have been found and analyzed

The dissertation thesis deals with the preparation and characterisation of a-CSi:H and a CSiO:H thin films prepared using the process of plasma enhanced chemical vapour deposition (PECVD). Tetravinylsilane (TVS) and its mixtures with argon and oxygen were used to deposit films on both planar substrates and fibre bundles. Main characterisation techniques were employed to study the topography of films, namely atomic force microscopy (AFM). Their mechanical properties were studied through nanoindentation; the nanoscratch test was used to assess the film adhesion to the substrate. Other analysed properties were internal stress and friction coefficient. The particular attention was paid to the work of adhesion and its determination. This knowledge was further applied to the preparation of surface treatments of glass fibres and, subsequently, polymer composites. Those were tested using the push-out test and the short beam shear test. Based on the results, the effects of deposition conditions and the relationships between the studied properties and quantities were determined.

Ce mémoire de maîtrise vise à étudier les propriétés physico-chimiques de couches minces organosiliciées produites par une décharge à barrière diélectrique à la pression atmosphérique (AP-DBD). Dans un premier temps, nous avons comparé des revêtements SiOCH sur verre obtenus en AP-DBD avec ceux produits dans un plasma à couplage capacitif à basse pression (LP-CCP). Dans les deux cas, en ayant recours à l’hexamethyldisiloxane et l’oxygène comme précurseurs chimiques pour le dépôt, on mesure un désordre structurel plus important avec une augmentation de la teneur en carbone dans la couche mince de SiOCH. On trouve également que la présence de groupes carbonés réduit leur adhésion au substrat. En particulier, la contrainte devant être appliquée avant qu’il y ait délamination semble fortement liée à la teneur en carbone. En dépit des différences dans les dynamiques de dépôt en AP-PECVD versus en LP-CCP, les procédés offrant des compositions chimiques similaires révèlent des propriétés mécaniques comparables (dureté, module de Young et élasticité). Dans un deuxième temps, nous avons déposé des couches minces SiOCH par AP-PECVD sur divers substrats polymériques à partir d’un précurseur cyclique (tetramethylcyclotetrasiloxane) plutôt que linéaire (hexamethyldisiloxane) dans un environnement semi-industriel. Dans ces conditions, les mesures de nanorayures (nanoscratch) indiquent que le substrat cède sous la contrainte appliquée avant qu’il y ait délamination de la couche mince déposée. De plus, en raison des faibles épaisseurs des revêtements, elles n’influencent pas réellement les propriétés mécaniques des substrats (dureté et module de Young). On note également que la teneur en carbone et la mouillabilité à l’eau sont étroitement liées à l’énergie déposée dans le plasma par molécule du précurseur. / This master thesis aims to examine the physicochemical properties of organosilicon thin films produced by atmospheric pressure, dielectric barrier discharges (AP-DBD). First, we compare SiOCH coatings deposited on glass by AP-DBD with those prepared by low-pressure, capacitively coupled plasma (LP-CCP). In both cases, using hexamethyldisiloxane and oxygen as chemical precursors for plasma deposition, a more important structural disorder was observed in SiOCH films with higher carbon content. We also show that the presence of functional carbon groups weakens the adhesion of the coatings to the substrate. In particular, the load needed to induce delamination seems to be strongly linked with the carbon content in the plasma deposited SiOCH thin films. Despite the differences in deposition dynamics in AP-PECVD versus LP-CCP, samples with similar chemical compositions reveal comparable mechanical properties (hardness, Young’s modulus, and elasticity index). Subsequently, we deposited SiOCH thin films by AP-PECVD on various polymeric substrates from a cyclic precursor (tetramethylcyclotetrasiloxane) instead of a linear one (hexamethyldisiloxane) in a semi-industrial environment. In these conditions, nanoscratch measurements indicate that the substrate breaks under load before any delamination of the coating can be observed. Furthermore, due to the low thickness of the plasma-deposited coatings, it is found that they do not influence the mechanical properties of the substrate (hardness and Young’s modulus). We also find that the carbon content and wettability with water are tightly related to the energy injected into the plasma per precursor molecules.

Magnesium alloys are being developed as advanced materials for structural applications where reduced weight is a primary motivator. Alloying can enhance the properties of magnesium without significantly affecting its density. Essential to alloy development, inclusive of processing parameters, is knowledge of thermodynamic, kinetic, and mechanical behavior of the alloy and its constituents. Appreciable progress has been made through conventional development processes, but to accelerate development of suitable wrought Mg alloys, an integrated Materials Genomic approach must be taken where thermodynamics and diffusion kinetic parameters form the basis of alloy design, process development, and properties-driven applications. The objective of this research effort is twofold: first, to codify the relationship between diffusion behavior, crystal structure, and mechanical properties; second, to provide fundamental data for the purpose of wrought Mg alloy development. Together, the principal deliverable of this work is an advanced understanding of Mg systems. To that end, the objective is accomplished through an aggregate of studies. The solid-to-solid diffusion bonding technique is used to fabricate combinatorial samples of Mg-Al-Zn ternary and Mg-Al, Mg-Zn, Mg-Y, Mg-Gd, and Mg-Nd binary systems. The combinatorial samples are subjected to structural and compositional characterization via Scanning Electron Microscopy with X-ray Energy Dispersive Spectroscopy, Electron Probe Microanalysis, and analytical Transmission Electron Microscopy. Interdiffusion in binary Mg systems is determined by Sauer-Freise and Boltzmann-Matano methods. Kirkaldy*s extension of the Boltzmann-Matano method, on the basis of Onsager*s formalism, is employed to quantify the main- and cross-interdiffusion coefficients in ternary Mg solid solutions. Impurity diffusion coefficients are determined by way of the Hall method. The intermetallic compounds and solid solutions formed during diffusion bonding of the combinatorial samples are subjected to nanoindentation tests, and the nominal and compositionally dependent mechanical properties are extracted by the Oliver-Pharr method. In addition to bolstering the scantly available experimental data and first-principles computations, this work delivers several original contributions to the state of Mg alloy knowledge. The influence of Zn concentration on Al impurity diffusion in binary Mg(Zn) solid solution is quantified to impact both the pre-exponential factor and activation energy. The main- and cross-interdiffusion coefficients in the ternary Mg solid solution of Mg-Al-Zn are reported wherein the interdiffusion of Zn is shown to strongly influence the interdiffusion of Mg and Al. A critical examination of rare earth element additions to Mg is reported, and a new phase in thermodynamic equilibrium with Mg-solid solution is identified in the Mg-Gd binary system. It is also demonstrated that Mg atoms move faster than Y atoms. For the first time the mechanical properties of intermetallic compounds in several binary Mg systems are quantified in terms of hardness and elastic modulus, and the influence of solute concentration on solid solution strengthening in binary Mg alloys is reported. The most significant and efficient solid solution strengthening is achieved by alloying Mg with Gd. The Mg-Nd and Mg-Gd intermetallic compounds exhibited better room temperature creep resistance than intermetallic compounds of Mg-Al. The correlation between the concentration dependence of mechanical properties and atomic diffusion is deliberated in terms of electronic nature of the atomic structure.

Die vorliegende Arbeit beschäftigt sich mit der Herstellung von CrNi-Stahl/Aluminium-Mischverbunden mit dem Ziel der Verbesserung der mechanischen Eigenschaften und der Erhöhung der Lebensdauer der Lötverbindungen. Da sich die Eigenschaften der Fügepartner stark unterscheiden, ist ein geeignetes Fügeverfahren erforderlich. Die wesentliche Herausforderung besteht in der Vermeidung der Bildung von dicken intermetallischen Schichten in der Reaktionszone, welche die mechanischen Eigenschaften der resultierenden Lötverbindungen verschlechtern. Dementsprechend wird ausgehend vom Stand der Technik ein Konzept zur vollständigen Untersuchung der Mikrostruktur-Eigenschafts-Beziehungen der Mischverbunde erarbeitet und umgesetzt. Die Mischverbunde werden durch Induktionslöten hergestellt, was einen lokalen Wärmeeintrag in die Fügestelle ermöglicht. Dadurch können Lötverbindungen mit dünnen Reaktionszonen erzeugt werden. Das Potenzial der Lötverbindungen wird anhand von Zugscher- und Ermüdungsversuchen aufgezeigt, die mit den Ergebnissen der Mikrostrukturanalyse und der fraktografischen Bewertung korreliert werden.:Abkürzungen und Formelzeichen iii Abkürzungen iii Formelzeichen iv Abbildungsverzeichnis v Tabellenverzeichnis xi 1 Einleitung und Motivation 1 2 Stand der Technik 2 2.1 Anwendungen von Stahl/Aluminium-Mischverbunden 2 2.2 Stoffschlüssiges Fügen von Stahl/Aluminium-Mischverbunden 3 2.2.1 Schweißen von Stahl/Aluminium-Mischverbunden 3 2.2.2 Löten von Stahl/Aluminium-Mischverbunden 8 2.2.2.1 Grundlagen 8 2.2.2.2 Verfahren und Lotwerkstoffe 10 2.3 Besonderheiten bei Stahl/Aluminium-Mischverbunden 15 2.3.1 Intermetallische Fe-Al-Verbindungen in der Reaktionszone 15 2.3.2 Kontrolle der Bildung und des Wachstums der Reaktionszone 20 2.3.3 Problematik bei mechanischer Charakterisierung der Mischverbunde 23 3 Folgerungen und Zielstellung 27 4 Experimentelle Durchführung 29 4.1 Grund- und Lotwerkstoffe 29 4.2 Benetzungs- und Lötversuche 31 4.3 Mikrostrukturelle Charakterisierung 34 4.3.1 Mikrostrukturanalyse 34 4.3.2 Mikrohärtemessung und Nanoindentation 35 4.3.3 Thermische Auslagerung 37 4.4 Mechanische Charakterisierung 39 4.4.1 Zugscher- und Warmzugscherversuche 39 4.4.2 Ermüdungsversuche 40 5 Ergebnisse 43 5.1 Benetzungsverhalten 43 5.2 Mikrostrukturelle Untersuchungen 45 5.2.1 Mikrostruktur der Lötverbindungen und Bildung der Reaktionszone 45 5.2.2 Mechanische Charakteristika der Gefügebestandteile 55 5.3 Festigkeitsuntersuchungen 59 5.3.1 Quasistatische Untersuchungen gelöteter Mischverbunde 59 5.3.2 Ermüdungsverhalten gelöteter Mischverbunde 69 5.4 Korrelation zwischen Reaktionszonendicke und Festigkeit 81 6 Diskussion der Ergebnisse 88 7 Zusammenfassung und Ausblick 92 8 Anlagen 93 8.1 Übersicht der Benetzungsproben auf Stahl X5CrNi18-10 93 8.2 Übersicht der Benetzungsproben auf AlMn1Cu 94 8.3 Beispiel der Ergebnisse der EDX-Analyse 95 8.4 Härteverlauf über die Reaktionszone 96 8.5 EBSD-Analyse der Lötverbindung 97 8.6 Mikrozugversuche 98 8.7 TEM-Untersuchungen der hergestellten Lötverbindungen 99 9 Literaturverzeichnis 102 10 Normenverzeichnis 112 11 Publikationen 113 / This thesis deals with the production of aluminum/stainless steel mixed joints in order to improve the mechanical properties and to extend the lifetime of the joints. Because of the different physical properties of the joining partners, a suitable joining technique is necessary. In comparison to welding, brazing offers significant advantages due to the lower liquidus temperature of the used brazing fillers. The main challenge is to prevent the formation of thick intermetallic layers in the reaction zone. These layers deteriorate the mechanical properties of the resulting joints predominantly. Correspondingly, a concept for the complete investigation of the microstructure-property relationships of the brazed joints is investigated. The joints are produced by induction brazing, which takes place in a short process time and allows a local heat input into the joint. Therefore, joints with a thin intermetallic layer in the reaction zone can be manufactured. The potential of the joints is demonstrated using monotonic tensile shear tests as well as fatigue tests. The achieved results are correlated with the results of the microstructural and fractographic analysis.:Abkürzungen und Formelzeichen iii Abkürzungen iii Formelzeichen iv Abbildungsverzeichnis v Tabellenverzeichnis xi 1 Einleitung und Motivation 1 2 Stand der Technik 2 2.1 Anwendungen von Stahl/Aluminium-Mischverbunden 2 2.2 Stoffschlüssiges Fügen von Stahl/Aluminium-Mischverbunden 3 2.2.1 Schweißen von Stahl/Aluminium-Mischverbunden 3 2.2.2 Löten von Stahl/Aluminium-Mischverbunden 8 2.2.2.1 Grundlagen 8 2.2.2.2 Verfahren und Lotwerkstoffe 10 2.3 Besonderheiten bei Stahl/Aluminium-Mischverbunden 15 2.3.1 Intermetallische Fe-Al-Verbindungen in der Reaktionszone 15 2.3.2 Kontrolle der Bildung und des Wachstums der Reaktionszone 20 2.3.3 Problematik bei mechanischer Charakterisierung der Mischverbunde 23 3 Folgerungen und Zielstellung 27 4 Experimentelle Durchführung 29 4.1 Grund- und Lotwerkstoffe 29 4.2 Benetzungs- und Lötversuche 31 4.3 Mikrostrukturelle Charakterisierung 34 4.3.1 Mikrostrukturanalyse 34 4.3.2 Mikrohärtemessung und Nanoindentation 35 4.3.3 Thermische Auslagerung 37 4.4 Mechanische Charakterisierung 39 4.4.1 Zugscher- und Warmzugscherversuche 39 4.4.2 Ermüdungsversuche 40 5 Ergebnisse 43 5.1 Benetzungsverhalten 43 5.2 Mikrostrukturelle Untersuchungen 45 5.2.1 Mikrostruktur der Lötverbindungen und Bildung der Reaktionszone 45 5.2.2 Mechanische Charakteristika der Gefügebestandteile 55 5.3 Festigkeitsuntersuchungen 59 5.3.1 Quasistatische Untersuchungen gelöteter Mischverbunde 59 5.3.2 Ermüdungsverhalten gelöteter Mischverbunde 69 5.4 Korrelation zwischen Reaktionszonendicke und Festigkeit 81 6 Diskussion der Ergebnisse 88 7 Zusammenfassung und Ausblick 92 8 Anlagen 93 8.1 Übersicht der Benetzungsproben auf Stahl X5CrNi18-10 93 8.2 Übersicht der Benetzungsproben auf AlMn1Cu 94 8.3 Beispiel der Ergebnisse der EDX-Analyse 95 8.4 Härteverlauf über die Reaktionszone 96 8.5 EBSD-Analyse der Lötverbindung 97 8.6 Mikrozugversuche 98 8.7 TEM-Untersuchungen der hergestellten Lötverbindungen 99 9 Literaturverzeichnis 102 10 Normenverzeichnis 112 11 Publikationen 113

No description available.