When tasks traditionally performed by humans are automated it is important thatthe machines are able to communicate how these tasks are solved and why. Whena user is surprised by the point of time where the task is executed, there is a needto be able to get an explanation to why this point in time was chosen.This project aims at investigating how intelligent systems in general, and case-based reasoning systems in particular can become explanation-aware. Our aim isprimarily to investigate existing case-based reasoning systems to see if explanation-awareness is achievable. Secondary, our aim is to develop a simple case-based rea-soning engine that complies with our theoretical work on explanation-awareness.

O processo de conformação por spray é interessante devido à capacidade de conjugar, em apenas uma etapa do processo, a vantagem da técnica de solidificação rápida combinada com alta produtividade dos processos de fundição convencional. Este processo permite a obtenção de materiais livre de macrossegregações, livre de porosidades e com microestrutura refinada. A evolução recente das pesquisas está levando ao desenvolvimento de novas ligas e os resultados têm sido interessantes. O processo de solidificação rápida inerente da conformação por spray permite a produção de ligas com composições diferentes das obtidas pela fundição convencional. O objetivo deste trabalho foi o de caracterizar mecanicamente uma liga de alumínio AA-6082 conformada por spray. Os resultados de testes de dureza Vickers são apresentados para seções de um preformado em relação a sua altura (em um arranjo tridimensional). O material foi avaliado na condição como conformado por spray e após tratamento térmico de solubilização a 525 ºC por 1 h, seguido por envelhecimento a 125 ºC por períodos distintos de 1 h, 10 h, 100 h e 500 h. É mostrado que o a liga AA 6082 conformada por spray mostra uma boa estabilidade térmica em relação a variação da dureza durante o envelhecimento. / The spray forming technology combines in a single step the advantages of the rapid solidification techniques and high the productivity of the conventional casting processes, allowing obtention of preforms with a refined microstructure, almost without porosity and macrosegregation free. The development and research efforts are leading to interesting alloys and materials production. The rapid solidification processes inherent to the spray forming allow the production of alloys with different compositions from those obtained by conventional ingot processes. The aim of this work was to carry out mechanical properties characterization of a spray formed AA-6082 alloy. The hardness results are presented in different sections related to the height of the spray formed preform (in a three-dimensional arrangement). The material was evaluated in the as sprayed condition and after heat treatment of solution at 525 ºC for 1 h, and aging for 1 h, 10 h, 100 h and 500 h periods. It was shown that the spray formed AA-6082 aluminum alloy is very stable regarding hardness variation during aging.

O processo de conformação por spray é interessante devido à capacidade de conjugar, em apenas uma etapa do processo, a vantagem da técnica de solidificação rápida combinada com alta produtividade dos processos de fundição convencional. Este processo permite a obtenção de materiais livre de macrossegregações, livre de porosidades e com microestrutura refinada. A evolução recente das pesquisas está levando ao desenvolvimento de novas ligas e os resultados têm sido interessantes. O processo de solidificação rápida inerente da conformação por spray permite a produção de ligas com composições diferentes das obtidas pela fundição convencional. O objetivo deste trabalho foi o de caracterizar mecanicamente uma liga de alumínio AA-6082 conformada por spray. Os resultados de testes de dureza Vickers são apresentados para seções de um preformado em relação a sua altura (em um arranjo tridimensional). O material foi avaliado na condição como conformado por spray e após tratamento térmico de solubilização a 525 ºC por 1 h, seguido por envelhecimento a 125 ºC por períodos distintos de 1 h, 10 h, 100 h e 500 h. É mostrado que o a liga AA 6082 conformada por spray mostra uma boa estabilidade térmica em relação a variação da dureza durante o envelhecimento. / The spray forming technology combines in a single step the advantages of the rapid solidification techniques and high the productivity of the conventional casting processes, allowing obtention of preforms with a refined microstructure, almost without porosity and macrosegregation free. The development and research efforts are leading to interesting alloys and materials production. The rapid solidification processes inherent to the spray forming allow the production of alloys with different compositions from those obtained by conventional ingot processes. The aim of this work was to carry out mechanical properties characterization of a spray formed AA-6082 alloy. The hardness results are presented in different sections related to the height of the spray formed preform (in a three-dimensional arrangement). The material was evaluated in the as sprayed condition and after heat treatment of solution at 525 ºC for 1 h, and aging for 1 h, 10 h, 100 h and 500 h periods. It was shown that the spray formed AA-6082 aluminum alloy is very stable regarding hardness variation during aging.

Vid extrudering av aluminiumprofiler introduceras en temperaturgradient i götmaterialet för att motverka den extra värme som uppstår under processen och tros påverka de mekaniska egenskaperna hos profilen. Detta examensarbete, utfört i samarbete med Hydro Extrusions, undersökte hur götets temperaturgradient påverkar de mekaniska egenskaperna hos extruderade aluminiumprofiler. Arbetet grundade sig i en modifierad DMAIC-metodik där Control-delen exkluderats. Dragprov genomfördes för att undersöka sträckgräns, brottgräns, töjning och elasticitetsmodul hos T4- och T6-åldrade profiler av legeringarna EN AW-6060 och EN AW-6082. Även profilernas utlöpningstemperatur, utlöpningshastighet och kylningshastighet undersöktes. Resultaten visade att temperaturgradienten inte direkt påverkade de mekaniska egenskaperna hos profilerna. Istället bidrog den till att maximera profilens utlöpningshastighet. De största faktorerna som påverkade de mekaniska egenskaperna var vilken åldring och kylningsmetod som användes. / During the extrusion of aluminum profiles, a temperature gradient is introduced into the billet to counteract the extra heat generated during the process and is believed to affect the mechanical properties of the profile. This thesis, carried out in collaboration with Hydro Extrusions, examined how the temperature gradient in the billet affects the mechanical properties of extruded aluminum profiles.  The work was based on a modified DMAIC methodology where the Control phase was excluded. Tensile tests were conducted to investigate the yield strength, ultimate tensile strength, elongation, and modulus of elasticity of T4- and T6-aged profiles of the alloys EN AW-6060 and EN AW-6082. The profile’s exit temperature, exit speed, and cooling rate was also investigated. The results showed that the temperature gradient did not directly affect the mechanical properties of the profiles. Instead, it contributed to maximizing the profile's exit speed. The largest factors influencing the mechanical properties were the aging and cooling methods used.

The project elaborated in frame of engineering studies branch Engineering technology submitted technology design of manufacturing a control element by extrusion – part of aluminium alloy EN AW 6082. On the base of literature study of the cold forming problems and calculations was designed procedure on one operation. Semi-finished product was chosen cut block rods with a diameter of 43.5 mm and length of 17,4 mm. The production is designed for toggle stamping press LLR 400 (producer Šmeral Brno a.s.) with a nominal force 4000 kN. Extrusion punch and extrusion die are made of steel alloy 19 830.4 heat-worked according to drawing documentation.

This project is a feasibility study for Hydro Extrusion Sweden AB, a company that produces extruded aluminium profiles. The main purpose of this project was to analyse the difference of Mg2Si particle sizes in aluminium alloys when varying parameters, such as cooling rate and composition, in aluminium extrusion, particularly the EN AW 6082 alloy. The Mg2Si particles have a great impact on the product’s mechanical properties. This was done in order to investigate whether real-time process parameter control is possible or not. The main software used was Thermo-Calc and the add-on module DICTRA. Thermo-Calc was used to do equilibrium calculations and gather data for the alloy and its phases. Based on this information and data from Hydro, simulations in DICTRA could be performed. The results were then plotted with respect to time and radius. The findings indicate that the cooling rate significantly influences the particle size. As the process becomes more intricate and involves a greater number of trace elements, adjusting the cooling rate could potentially be employed as a means to address this issue. The results also showed that trace elements had a minimal effect on the particle size. However, this probably does not match the reality since other phases affect and block the growth of Mg2Si.The overall results indicate a positive outcome for using DICTRA in determining particle sizes. However, further research needs to be done in correlation with more experiments before this could be a viable research method for Hydro. / Det här projektet är en förstudie för företaget Hydro Extrusion Sweden AB som producerar extruderade aluminiumprofiler. Det huvudsakliga syftet med projektet var att analysera skillnaden på Mg2Si-partiklarnas storlek i aluminiumlegeringar när olika parametrar som kylhastighet och sammansättning användes vid aluminiumextrudering, mer specifikt legeringen EN AW 6082. Mg2Si partiklarna har stor betydelse för produktens mekaniska egenskaper. Syftet med detta var att undersöka huruvida det är möjligt att styra process parametrarna i realtid. Mjukvaran som användes var Thermo-Calc och tilläggsmodulen DICTRA. Thermo-Calc användes för att göra jämviktsberäkningar och samla in data för legeringen samt dess faser. Baserat på denna information och data från Hydro kunde simuleringar i DICTRA utföras. Resultaten plottades sedan med avseende på tid och radie. Partikelstorleken påverkas avsevärt av kylningshastigheten enligt resultaten. I framtiden, när processen blir mer avancerad med fler spårämnen, kan det vara möjligt att justera kylningshastigheten för att hantera detta. Resultaten visade också att spårämnen hade en mycket liten effekt på partikelstorleken. Detta stämmer dock förmodligen inte med verkligheten eftersom andra faser påverkar och blockerar tillväxten av Mg2Si. De övergripande resultaten pekar på ett positivt resultat för att använda DICTRA för att bestämma partikelstorlekar. Ytterligare forskning måste göras i samband med fler experiment innan detta kan vara en genomförbar forskningsmetod för Hydro.

Das Ziel dieser Arbeit besteht in der Erforschung des Zusammenhangs zwischen der Struktur der Metalloberfläche und der Verbundfestigkeit von thermisch gefügten Thermoplast-Metall-Verbunden. Dazu wird für die Haftungsmechanismen Stoff-, Kraft- und Formschluss an einem Minimalbeispiel rechnerisch gezeigt, dass verschiedene Oberflächenmerkmale (wahre Oberfläche, Strukturdichte, Aspektverhältnis, Hinterschnitte, Substrukturen) mit der Verbundfestigkeit in Verbindung stehen. Basierend darauf werden Oberflächenkenngrößen (standardisierte Rauheitsparameter, fraktale Dimension) gewählt, die die haftungsfördernden Strukturmerkmale möglichst umfassend einbeziehen. Daraus werden Hypothesen abgeleitet, die die Prognostizierbarkeit der Verbundfestigkeit aus Oberflächenkenngrößen für Thermoplast-Metall-Verbunde postulieren. Die experimentelle Überprüfung erfolgt an Aluminium im Verbund mit Polyamid 6 bzw. Polypropylen in Rohrtorsions-, Rohrzug- sowie Zugscherversuchen. Die Einstellung der Oberflächenstruktur des Aluminiums erfolgt durch mechanisches Strahlen, alkalisches Ätzen, thermisches Spritzen sowie Laserstrukturieren. Die Erfassung der Oberflächenstruktur erfolgt taktil sowie aus Querschliffaufnahmen. Die Höhe der Verbundfestigkeit kann anhand der Oberflächenstruktur erklärt und teilweise mit hoher Korrelation quantitativ in Verbindung gebracht werden. Bei taktiler Messung verhindert jedoch eine unzureichende Erfassung bestimmter Strukturmerkmale eine exakte Abbildung der tatsächlichen Oberflächenstruktur. Bei der Erfassung der Oberflächenstruktur aus Querschliffaufnahmen stellt die erreichbare Bildauflösung und -qualität einen limitierenden Faktor dar. Ebenso können aus der Oberflächenstruktur keine individuellen, strukturspezifischen Versagensmechanismen abgeleitet werden.:Inhaltsverzeichnis 5 Abbildungsverzeichnis 9 Tabellenverzeichnis 14 Abkürzungsverzeichnis 16 Symbolverzeichnis 17 1 Motivation 20 2 Stand der Wissenschaft und Technik 22 2.1 Verwendete Begriffe 22 2.2 Verbundwerkstoffe und Werkstoffverbunde 22 2.2.1 Faser-Kunststoff-Verbunde 24 2.2.2 Polymer-Metall-Verbunde 25 2.3 Fügen von Polymer-Metall-Verbunden 27 2.3.1 In-Mold Assembly 28 2.3.2 Kleben 28 2.3.3 Montage 29 2.3.4 Thermisches Fügen 31 2.4 Prüfung der Verbundfestigkeit 34 2.4.1 Prüfkörpergeometrien 34 2.4.2 Beständigkeit gegen Umwelteinflüsse 36 2.5 Verfahren zur Vorbehandlung der Metalloberfläche 38 2.5.1 Mechanisches Strahlen 39 2.5.2 Laserstrukturieren 40 2.5.3 Chemische und elektrochemische Verfahren 43 2.5.4 Beschichten 43 2.5.5 Weitere Verfahren 44 3 Zusammenhang zwischen Oberflächenstruktur und Verbundfestigkeit 46 3.1 Haftungsmechanismen 47 3.1.1 Stoffschluss 48 3.1.2 Kraftschluss 50 3.1.3 Formschluss 51 3.1.4 Skalenabhängigkeit 53 3.1.5 Eigenspannungen 54 3.1.6 Folgerungen 54 3.2 Charakterisierung der Oberflächenstruktur und Korrelation mit der Verbundfestigkeit 55 3.2.1 Standardisierte Rauheitsparameter 56 3.2.2 Fraktale Dimension 58 3.2.3 Anwendungsbeispiel 59 4 Zielstellung 62 4.1 Folgerungen aus dem Stand der Wissenschaft und Technik 62 4.2 Forschungshypothesen 63 5 Experimentelle Vorgehensweise 64 5.1 Charakterisierung der Ausgangswerkstoffe 64 5.2 Vorbehandlung der Metalloberflächen 67 5.2.1 Mechanisches Strahlen und alkalisches Ätzen 67 5.2.2 Thermisches Spritzen 68 5.2.3 Laserstrukturieren 68 5.3 Charakterisierung der Oberflächenstruktur 69 5.4 Mechanische Verbundprüfung 71 5.5 Verwendeter Fügeprozess 73 5.6 Statistische Betrachtung 75 6 Ergebnisse und Diskussion 77 6.1 Verbundfestigkeit in Abhängigkeit von der Oberflächenvorbehandlung 77 6.1.1 Rohrproben 77 6.1.1.1 Oberflächencharakteristika und Benetzung 77 6.1.1.2 Verbundfestigkeit und Korrelation mit Oberflächenkennwerten 81 6.1.1.3 Bruchflächenanalyse 85 6.1.2 Zugscherproben 90 6.1.2.1 Oberflächencharakteristika und Benetzung 90 6.1.2.2 Verbundfestigkeit und Korrelation mit den Oberflächenkennwerten 91 6.1.2.3 Bruchflächenanalyse 93 6.1.3 Ergebnisdiskussion 95 6.2 Verbundfestigkeit in Abhängigkeit von der Skalierung 97 6.2.1 Oberflächencharakteristika und Benetzung 97 6.2.2 Verbundfestigkeit und Korrelation mit Oberflächenkennwerten 102 6.2.3 Bruchflächenanalyse 102 6.2.4 Ergebnissdiskussion 106 7 Zusammenfassung und Folgerungen 108 8 Ausblick 112 Literaturverzeichnis 115 Anhang 129 / The aim of this work is to investigate the relationship between the structure of the metal surface and the compound strength of thermally joined thermoplastic-metal compounds. For this purpose, equations are derived for the adhesion mechanisms of material, force and form closure using a minimal example, which link various surface characteristics (true surface, structure density, aspect ratio, undercuts, substructures) with the compound strength. Based on this, surface parameters (standardized roughness parameters, fractal dimension) are chosen that incorporate the adhesion-promoting structural features as comprehensively as possible. From this, hypotheses are derived that postulate the predictability of compound strength from surface parameters for thermoplastic-metal composites. Experimental verification is carried out on aluminum in compounds with polyamide 6 or polypropylene in hollow cylinder torsion tests, hollow cylinder tensile tests as well as tensile shear tests. The surface of the aluminum is structured by mechanical blasting, alkaline etching, thermal spraying and laser structuring. The surface structure is recorded tactilely and from transverse micrographs. The height of the compound strength can be explained on the basis of surface structure and, in part, quantitatively related with high correlation. However, in the case of tactile measurement, nondetection of certain structural features prevents accurate mapping of the actual surface structure. When recording the surface structure from cross-section images, the achievable image resolution and quality is the limiting factor. Likewise, no individual, structure-specific failure mechanisms can be derived from the surface structure.:Inhaltsverzeichnis 5 Abbildungsverzeichnis 9 Tabellenverzeichnis 14 Abkürzungsverzeichnis 16 Symbolverzeichnis 17 1 Motivation 20 2 Stand der Wissenschaft und Technik 22 2.1 Verwendete Begriffe 22 2.2 Verbundwerkstoffe und Werkstoffverbunde 22 2.2.1 Faser-Kunststoff-Verbunde 24 2.2.2 Polymer-Metall-Verbunde 25 2.3 Fügen von Polymer-Metall-Verbunden 27 2.3.1 In-Mold Assembly 28 2.3.2 Kleben 28 2.3.3 Montage 29 2.3.4 Thermisches Fügen 31 2.4 Prüfung der Verbundfestigkeit 34 2.4.1 Prüfkörpergeometrien 34 2.4.2 Beständigkeit gegen Umwelteinflüsse 36 2.5 Verfahren zur Vorbehandlung der Metalloberfläche 38 2.5.1 Mechanisches Strahlen 39 2.5.2 Laserstrukturieren 40 2.5.3 Chemische und elektrochemische Verfahren 43 2.5.4 Beschichten 43 2.5.5 Weitere Verfahren 44 3 Zusammenhang zwischen Oberflächenstruktur und Verbundfestigkeit 46 3.1 Haftungsmechanismen 47 3.1.1 Stoffschluss 48 3.1.2 Kraftschluss 50 3.1.3 Formschluss 51 3.1.4 Skalenabhängigkeit 53 3.1.5 Eigenspannungen 54 3.1.6 Folgerungen 54 3.2 Charakterisierung der Oberflächenstruktur und Korrelation mit der Verbundfestigkeit 55 3.2.1 Standardisierte Rauheitsparameter 56 3.2.2 Fraktale Dimension 58 3.2.3 Anwendungsbeispiel 59 4 Zielstellung 62 4.1 Folgerungen aus dem Stand der Wissenschaft und Technik 62 4.2 Forschungshypothesen 63 5 Experimentelle Vorgehensweise 64 5.1 Charakterisierung der Ausgangswerkstoffe 64 5.2 Vorbehandlung der Metalloberflächen 67 5.2.1 Mechanisches Strahlen und alkalisches Ätzen 67 5.2.2 Thermisches Spritzen 68 5.2.3 Laserstrukturieren 68 5.3 Charakterisierung der Oberflächenstruktur 69 5.4 Mechanische Verbundprüfung 71 5.5 Verwendeter Fügeprozess 73 5.6 Statistische Betrachtung 75 6 Ergebnisse und Diskussion 77 6.1 Verbundfestigkeit in Abhängigkeit von der Oberflächenvorbehandlung 77 6.1.1 Rohrproben 77 6.1.1.1 Oberflächencharakteristika und Benetzung 77 6.1.1.2 Verbundfestigkeit und Korrelation mit Oberflächenkennwerten 81 6.1.1.3 Bruchflächenanalyse 85 6.1.2 Zugscherproben 90 6.1.2.1 Oberflächencharakteristika und Benetzung 90 6.1.2.2 Verbundfestigkeit und Korrelation mit den Oberflächenkennwerten 91 6.1.2.3 Bruchflächenanalyse 93 6.1.3 Ergebnisdiskussion 95 6.2 Verbundfestigkeit in Abhängigkeit von der Skalierung 97 6.2.1 Oberflächencharakteristika und Benetzung 97 6.2.2 Verbundfestigkeit und Korrelation mit Oberflächenkennwerten 102 6.2.3 Bruchflächenanalyse 102 6.2.4 Ergebnissdiskussion 106 7 Zusammenfassung und Folgerungen 108 8 Ausblick 112 Literaturverzeichnis 115 Anhang 129

This diploma thesis is concerned with the numerical analysis of welded aluminim structures. In these structures, there are significant decreases in the mechanical properties at the area of the weld and in the heat affected zone as a result of welding. Within this thesis, simulations of quasi-statically loaded welded joints made from EN AW-6082 T6 alloy were performed to investigate the load capacity and ductility of these joints. Computations were performed using a programme system based on an explicit finite element method. To describe material anisotrophy, a nonlinear material model called the Weak texture model was chosen. Material properties of the weld and the heat affected zone were considered to be different from base material. The required material parameters were adopted from available literature, however, material tests and indetification procedure of these parameters were described. In comparison with the experimental data, the results of the numerical simulations showed a relatively good ability of models to capture load capacity of studied welded joints. Nevertheless, due to mesh sensitivity of models caused by localization of deformation, it was not possible to determine ductility of these joints.