University Of Kaiserslautern Research Articles

An open chat with… Johannes Herrmann.

Johannes Herrmann is a Professor of Cell Biology at the University of Kaiserslautern in Germany. His research focus is centred on the biogenesis of mitochondrial proteins. Johannes is a member of the German Academy of Sciences and member of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Biochemistry Panel. He has been a member of the FEBS Publication Committee since 2021. In this interview, he explains the source of his scientific interest in mitochondrial biology and details how the work of the FEBS Publication Committee safeguards the future of the FEBS Press journals.

Difficulties in the Implementation of International Academic Mobility Programs: Student’s Stance. Russian-German Experience in Solving Problems in the Context of the COVID-19 Pandemic

Introduction. Academic mobility of students is an integral part of quality higher education in Russia. A frequent problem is a difficult adaption to a foreign country. The article looks into to the problem of offsetting negative consequences of cultural adaptation of Russian students in German universities during short-term stay. The aim of the article is to work out recommendations on preliminary preparation of short-term international academic mobility programs between Russian and foreign partner universities, taking into account cultural adaptation of students. Materials and Methods. The research draws on surveys of students participating in the 6-month (1 semester) international Russian-German academic mobility program. As a survey technique, a group continuous correspondence survey was employed. The questionnaire was compiled following the conditions of relevance and representativeness using empirical indicators and descriptive statistics. The method of statistical factor analysis served a tool to identify the main factors influencing the quality of adaptation; for a comparative analysis of the results of the survey, statistical methods of comparing averages and statistical visualization were used. Results. The article analyzes the results of surveys of students of the German-Russian Institute of Advanced Technologies about the main points of education in Germany that cause them difficulties. A comparative analysis of learning in the context of the COVID-19 pandemic (hybrid, almost completely remote learning) with the period before the pandemic (full face-to-face learning) was made. Conclusions are drawn about the prevailing factors that influenced the success of learning in both cases. Examples of practical recommendations are formulated as to the necessary preparation of Russian university students for studying at European universities in the years following the pandemic, taking into account the results of surveys of teachers from the host German university, as well as the observations of an expert from the Kazan National Research Technical University over the teaching process at the Technical University of Kaiserslautern. Based on the results of the analysis of factors most affecting the success of Russian students in a foreign university, we propose measures aimed at accelerating and mitigating the adaptation of Russian-speaking students to a long stay in a foreign environment. In the aftermath of the COVID-19 pandemic, the hybrid form of education looks most effective, as it increases the success of Russian students studying abroad. Discussion and Conclusion. The proposed approach to the assessment of influencing factors and the developed methods for their elimination will help prevent similar problems in the future. The conclusions made by the authors contribute to the practice of short-stay international academic mobility organization. The article materials are of interest to the scientific and pedagogical community, faculty and management of educational institutions.

Revitalization of brownfields in shrinking cites exemplified by the urban farm in Dessau a Green Innovation area as a part of the BMBF project GIAGEM

This bachelor thesis is about the revitalization of urban brownfields in shrinking cities. The project "Urban Farm Dessau" is used throughout the thesis as an example. Different social processes, such as structural change and demographic change, lead to changed conditions in cities. One consequence of this is that shrinking processes are continuing and this leads to the creation of brownfields, which are often not used again. This process of urban sprawl often results in the decline of districts or entire cities. In the project GIAGEM "The Role of Green Innovation Areas in Revitalizing German and Mexican Cities" of the Technical University of Kaiserslautern and the University of Guadalajara, alternative solutions for the revitalization of such brownfields are being developed, which at the same time meet bio-economic requirements. Various sustainable and efficient uses are analysed and evaluated on the basis of example projects and their transferability to other cities is specified. First of all, the scientific framework conditions are elaborated in this thesis. For this purpose, the key words "Brownfields", "Revitalization" and "Urban Farming" will be defined and classified. The project GIAGEM will be presented in more detail in order to establish the connection to the chosen example project "Urban Farm Dessau". The project "Urban Farm Dessau", which was developed in the city of Dessau-Roßlau, in the district Am Leipziger Tor in Sachsen-Anhalt, will be analysed in more detail by means of a preliminary study and with the help of an area reference. The project is finally evaluated by means of a criteria grid. The results of the evaluation form the basis for recommendations for action, which represent a possibility of transferability of this project to other cities and locations. Finally, a conclusion about the project is given, summarizing the knowledge gained from the analysed chapters and evaluating whether the Urban Farm is a suitable form of sustainable brownfield revitalization and an innovative approach for sustainable urban development.

A day in the life of a biopharmaceutical senior scientist

Dr Jana Broecker is a senior scientist in the Biochemistry Department at Sosei Heptares in the UK, where she is part of a team that develops small-molecule therapeutics using protein structural information. Jana graduated as a Diploma Engineer from the Technical University Berlin (Germany) and did her PhD with the University of Kaiserslautern on the biophysical quantification of membrane-protein stability. She also completed post-doctoral research at the University of Toronto (Canada), where she spearheaded the optimization of membrane-protein crystallization using polymer-bound lipid nanodiscs and where she also developed a method that avoids crystal harvesting.

Turbine Vane Endwall Film Cooling Effectiveness of Different Purge Slot Configurations in a Linear Cascade

Abstract This study is concerned with the film cooling effectiveness of the flow issuing from the gap between the nozzle guide vane (NGV) and the transition duct on the NGV endwall, i.e., the purge slot. Different slot widths, positions, and injection angles were examined in order to represent changes due to thermal expansion as well as design modifications. Apart from these geometric variations, different blowing ratios (BRs) and density ratios (DRs) were realized to investigate the effects of the interaction between secondary flow and film cooling effectiveness. The experimental tests were performed in a linear scale-1 cascade equipped with four highly loaded turbine vanes at the Institute of Fluid Mechanics and Fluid Machinery of the University of Kaiserslautern. The mainstream flow parameters were, with a Reynolds number of 300,000 and a Mach number (outlet) of 0.6, set to meet real engine conditions. By using various flow conditioners, periodic flow was obtained in the region of interest (ROI). The adiabatic film cooling effectiveness was determined using the pressure sensitive paint (PSP) technique. In this context, nitrogen and carbon dioxide were used as tracer gases realizing two different density ratios DR = 1.0 and 1.6. The investigation was conducted for a broad range of blowing ratios with 0.25 ≤ BR ≤ 1.50. In combination with 10 geometry variations and the aforementioned blowing and density ratio variations, 100 single operating points were investigated. For a better understanding of the coolant distribution, the secondary flows on the endwall were visualized by oil dye. The measurement results will be discussed based on the areal distribution of film cooling effectiveness, its lateral spanwise, as well as its area average. The results will provide a better insight into various parametric effects of gap variations on turbine vane endwall film cooling performance—notably under realistic engine conditions.

ДОСЛІДЖЕННЯ УДАРНОЇ ПОВЕДІНКИ ЧАСТКИ ПРИ ВЗАЄМОДІЇ З ПІДКЛАДКОЮ МЕТОДОМ КІНЦЕВИХ ЕЛЕМЕНТІВ

Purpose of the work: determination of the characteristics of the interaction between the particle and the lining in cold gas-dynamic spraying. Research methods: the finite element method was used in modeling the process. Results: In this work, the impact behavior of a particle upon interaction with a lining during cold gas-dynamic spraying is investigated. In the process of performing the work, the FEM ABAQUS / Explicit program was used. The study consists of the following stages: simulation of a particle and a substrate using various parameters of the Johnson-Cook steel material, particle sizes and other parameters; analysis of the effect of different particle impact velocities for different Johnson - Cook parameters (the same for a particle and a substrate), an analysis of previous results at different temperatures (for particles) is ISSN 2308-5312 Наукові праці ДонНТУ. Серія: «Машинобудування і машинознавство». No1(14)’2020 36 carried out. The article presents the results of studies carried out in the laboratories of the Technical University of Kaiserslautern (Germany) under the DAAD international scientific cooperation program. Scientific novelty: a methodology has been developed for modeling the process of interaction between the particle and the lining. Practical value: the methods of modeling and experimental study of the impact behavior of a particle when interacting with a lining presented in the article can be used in the design and modernization of technological equipment

Power loss reduction in timing chain drives by adjusted tensioning and surface structuring

Purpose Energy losses in a timing chain drives are caused by friction in chain-rail contacts. To improve the efficiency, the Chair of Machine Elements and Transmission Technology at the University of Kaiserslautern developed various experimental and simulative analysis tools as a part of the German Research Foundation (DFG)-funded 1551 priority program and the DFG Collaborative Research Centre CRC 926. With these tools, various approaches for improving the efficiency were investigated. This paper aims to illustrate the approaches and present the results achieved within the framework of the above-mentioned priority program. Design/methodology/approach A towed cylinder head test rig is used for efficiency tests on timing chain drives. In addition to the experiments, a multi-body simulation model of the timing drive was developed and used. Findings It was possible to find positive approaches to reduce friction power by adapting the chain tensioning force as required. This was ensured for both the stationary operating points and the transient operating processes. An efficiency improvement of up to 10 per cent could be detected. Furthermore, a possibility was found to improve the frictional power by a targeted lubrication of the chain-rail contact. Here, the efficiency could be improved by 5-6 per cent. In addition, various structures were examined on a microscopic and macroscopic level. Neutral to negative results were achieved here. Originality/value This paper makes a contribution to improve the energy efficiency of timing chain drives. Different approaches have been investigated and evaluated.

Seismic out‐of‐plane behavior of unreinforced masonry walls

AbstractUnreinforced masonry (URM) is one of the most used construction types in the world. In addition to the design for static loads, URM walls must also be designed for earthquake scenarios. In this load case, the out‐of‐plane loads (transverse to the plane) often have a significant impact on the load‐bearing capacity. In most practical applications, simplified methods are used to determine the out‐of‐plane capacity of URM walls. The estimations of these simplified models are often inaccurate since essential parameters are neglected. To determine out‐of‐plane capacity realistically, parameters such as vertical stiffness of the support, geometry, constraints, vertical loads, and dynamic effects must be taken into account. At the University of Kaiserslautern, shaking‐table tests with different conditions of upper support are performed. Real earthquake time histories are applied and increased until collapse of the wall. For numerical analyses of the deformation response of the wall, nonlinear single‐degree‐of‐freedom systems are developed and calibrated. In addition, results from simplified analysis models are compared with experimentally determined maximum acceptable earthquake accelerations. The comparison shows that the out‐of‐plane capacity is much higher than predicted by simplified models. The experimental, analytical, and numerical investigations on URM walls will be used to develop a simple and practical applicable engineering model in the next phase of the project.

Impedance Of 3D Nanostructured MEAs: Influence of Coating and Cell Cultivation

Impedance Of 3D Nanostructured MEAs: Influence of Coating and Cell Cultivation

Improving Thermal Insulation Properties for Prefabricated Wall Components Made Of Lightweight Aggregate Concrete with Open Structure

Porous concrete is commonly used in civil engineering due to its good thermal insulation properties in comparison with normal concrete and high compression strength in comparison with other building materials. Reducing of the concrete density can be obviously obtained by using lightweight aggregate (e.g. pumice). The concrete density can be further minimized by using specially graded coarse aggregate and little-to-no fine aggregates. In this way a large number of air voids arise. The aggregate particles are coated by a cement paste and bonded together with it just in contact points. Such an extremely porous concrete, called ‘lightweight aggregate concrete with open structure’ (LAC), is used in some German plants to produce prefabricated wall components. They are used mainly in hall buildings, e.g. supermarkets. The need of improving thermal insulation properties was an inspiration for the prefabrication plant managers, engineers and a scientific staff of the Technical University of Kaiserslautern / Germany to realise an interesting project. Its aim was to reduce the heat transfer coefficient for the wall components. Three different wall structure types were designed and compared in full-scale laboratory tests with originally produced wall components in terms of load-carrying capacity and stiffness. The load was applied perpendicularly to the wall plane. As the components are not originally used for load-bearing walls, but for curtain walls only, the wind load is the main load for them. The wall components were tested in horizontal position and the load was applied vertically. Totally twelve wall components 8.00 × 2.00 × 0.25m (three for every series) were produced in the prefabrication plant and tested in the University of Kaiserslautern laboratory. The designed and tested components differed from each other in the amount of expanded polystyrene (EPS), which was placed in the plant inside the wall structure. The minimal amount of it was designed in the original wall component type. Besides, two improved types of prefabricated wall had built-in steel lattice girders. The failure mode was the same for all the tested components: diagonal cracks occurred on the sides of each component due to their insufficient shear-force-capacity. The span deflection was measured during all the tests by means of LVDTs. Load-carrying capacities obtained in the tests were for all wall structure types similar and much higher (many times) than internal forces (i.e. bending moments and shear forces) calculated for a wind load acting on a typical hall building according to the German codes. An increased amount of EPS (up to 30 per cent in volume) did not influence significantly the wall structural strength. The use of the steel lattice girders caused some technological problems and led to a quality loss of the produced components. The future use of the lattice girders would require a change in the production process: it would have to be more labour consuming.

Ultrasonic Torsion Welding of Aging Resistant Al/CFRP Joints - Concepts, Mechanical and Microstructural Properties

Multi-material-design offers high potential for weight saving and optimization of engineering structures but inherits challenges as well, especially robust joining methods and long-term properties of hybrid structures. The application of joining techniques like ultrasonic welding allows a very efficient design of multi-material-components to enable further use of material specific advantages and are superior concerning mechanical properties.The Institute of Materials Science and Engineering of the University of Kaiserslautern (WKK) has a long-time experience on ultrasonic welding of dissimilar materials, for example different kinds of CFRP, light metals, steels or even glasses and ceramics. The mechanical properties are mostly optimized by using ideal process parameters, determined through statistical test planning methods.This gained knowledge is now to be transferred to application in aviation industry in cooperation with CTC GmbH and Airbus Operations GmbH. Therefore aircraft-related materials are joined by ultrasonic welding. The applied process parameters are recorded and analyzed in detail to be interlinked with the resulting mechanical properties of the hybrid joints. Aircraft derived multi-material demonstrators will be designed, manufactured and characterized with respect to their monotonic and fatigue properties as well as their resistance to aging.

Development of a Sensor Prototype and Geometry Based Parameters for the Characterization of Riblets Using Angle-resolved Measurement Techniques

The application of periodic microscale-structures, so-called riblets, is a medium-term goal intended to help airplane manufacturers in the modern civil aviation industry to reduce fuel consumption of aircrafts significantly. To reach this goal it is necessary to investigate the quality of riblets during the manufacturing process as well as during the operating time. Thus, it is essential to measure the degradation of those microscopic structures as a function of flight time in order to reach a decision on whether to replace or to rework the existing riblets. Tactile measurement principles are being disqualified for practical applications for several reasons. Instead, optical measurement principles are well-suited for this kind of application. The angle-resolved scattering light principle describes such an optical measurement method, which is suitable for measuring riblet structures and moreover can be virtually modeled. Based on theoretical pre-examinations of the physical measurement principle, a virtual sensor has been developed at the Institute for Measurement and Sensor-Technology at the University of Kaiserslautern to investigate riblet degradation. This was achieved within the framework of the International Research and Trainee Group 2057 (IRTG 2057), founded by the German Research Foundation (DFG). This virtual sensor forms the basis of a prototype, the so-called riblet sensor, which is currently being subjected to practical testing. A comparison between virtual and real measurement data is thus possible.To ultimately get meaningful results regarding the qualitative conditions of the riblets, so-called scatter distributions must be analyzed and interpreted. An unambiguous interpretation of scatter distributions presents difficulties. The development of applicable parameters based on virtual data analysis therefore is a significant aspect, which will be considered within this article. Furthermore detailed physical descriptions of the virtual sensor will be given.

Manufacturing of new roughness standards for the linearity of the vertical axis – Feasibility study and optimization

In order to provide an alternative for the vertical axis calibration of stylus instruments which is usually performed based on step height standards, a new measurement standard geometry for the calibration of the linearity and research on its manufacturing is needed. For the manufacturing of these geometric measurement standards there is, according to the type of the measurement standard, a broad range of manufacturing processes that can be applied. New measurement standards for the roughness calibration were developed at the University of Kaiserslautern and an ultra-precision turning process was chosen for its manufacturing. The paper presents a feasibility study of the chosen manufacturing process. The aim of the investigations is to present the development of the standard and the qualification of the ultra-precision turning process for the manufacturing of calibration standards. An examination was performed in order to characterize the influences of different process parameters on the quality of the manufactured roughness standard.

The alkaline comet assay as a method to investigate the DNA strand breaking effect of phenylpropanoids in mammalian cells

Event Abstract Back to Event The alkaline comet assay as a method to investigate the DNA strand breaking effect of phenylpropanoids in mammalian cells Sabrina Haupenthal1, Sabrina Vallicotti2, Melanie Hemgesberg2 and Melanie Esselen1* 1 University of Münster, Institute of Food Chemistry, Germany 2 University of Kaiserslautern, Department of Food Chemistry and Toxicology, Germany The propenylic α-asarone (aA) and β-asarone (bA) as well as the allylic γ-asarone (gA) are naturally occurring constituents in several herbs and spices such as Acorus calamus (aA and bA) or Aniba hostmanniana (gA). Alcoholic beverages, teas, herbal medicine and cosmetics exhibit the most important route for human exposure [1]. aA and bA are classified as carcinogenic in rodents, whereas the data for gA is very limited so far [2]. For risk assessment further cellular studies about genotoxicity are required, so the question was addressed, whether the asarone isomers induce DNA strand breaks. Therefore, a modified alkaline comet assay to investigate DNA strand breaking effects of the asarone isomers in hamster lung fibroblasts (V79 cells and with human cytochrome P450 1A2 and human sulfotransferase 1C2 transfected V79 cells) was used. Furthermore, the DNA repair enzyme formamidopyrimidine DNA glycosylase (FPG) as a marker for oxidative DNA damage was also included in our test system. aA, bA as well as gA significantly induce DNA damage in V79 cells at concentrations > 10 µM. However, no enhanced DNA damage was observed after FPG-incubation of V79 cells. In contrast, in metabolic competent transfected V79 cells both propenylic asarone derivatives aA and bA significantly increase the amount of FPG-sensitive sites, whereas the allylic compound gA was not effective. This study assumes that an impact on the cellular redox status of the propenylic asarone isomers and their respective metabolites might contribute to their genotoxic properties. In conclusion, further in vitro studies on DNA damage and repair to elucidate the mechanism of genotoxicity and mutagenicity of these carcinogenic plant constituents are still under investigation.

Fatigue testing of CFRP in the Very High Cycle Fatigue (VHCF) regime at ultrasonic frequencies

Carbon fiber reinforced polymers (CFRP) are more and more used for high performance applications such as aircraft structures. These structural components are subjected with more than 108 cycles during their lifetime. At present the fatigue behavior of CFRP and the corresponding failure mechanisms are not sufficiently investigated in the VHCF regime. To obtain comprehensive knowledge about the fatigue behavior as well as the failure mechanisms of CFRP in the Very High Cycle Fatigue (VHCF) regime, a new Ultrasonic Testing Facility (UTF) for cyclic three point bending of CFRP at 20 kHz has been developed at the Institute of Materials Science and Engineering (WKK), University of Kaiserslautern. This UTF with combined online nondestructive testing via laser vibrometry and IR-thermography enables VHCF experiments up to 109 cycles in twelve days. All experiments are carried out at a stress ratio between 0.29 and 0.49. To keep the specimen temperature below the glass transition temperature of the CFRP the cyclic bending load is divided in pulse pause sequences. The specimen material used in this investigation is a commercially available carbon fiber fabric reinforced polyphenylensulfide (CF-PPS). For the accurate calibration of the loads as well as for the visualization of the strain distribution and the oscillation mode, measurements with 3D-scanning-laser-vibrometry have been carried out. Furthermore light optical micrographs plus SEM investigations have been performed upon completion and in defined interceptions of the experiments. Based on the results of the microscopic investigations the failure mechanisms of CF-PPS for the VHCF are described.

Realization of Al/Mg-Hybrid-Joints by Ultrasound Supported Friction Stir Welding - Mechanical Properties, Microstructure and Corrosion Behavior

Fusion welding of dissimilar metals is in the most cases difficult or even impossible as a result of different melting points and the development of undesirable brittle intermetallic phases. This often leads to joint strengths considerable below the tensile strength of the base materials. By using Friction Stir Welding (FSW) it is possible to reduce the development of the intermetallic phases of Al/Mg-joints significantly but not to avoid them completely. Hence a hybrid welding system at the WKK of the University of Kaiserslautern was developed called “Ultrasound Supported Friction Stir Welding (US-FSW)” with the aim to shatter the brittle interlayer lines and to scatter fragments in the welding area during the FSW process. Pre-investigations have shown that for Al/Mg-US-FSW-joints the strength can be increased up to 30% in comparison to conventional FSW. Moreover for the reliable detection of nonconformities in the weld during a post-process inspection by suitable non-destructive testing (NDT) methods is necessary. Also there is a strong need for better process monitoring and control by in-process NDT methods. Furthermore the corrosion behavior of the basic materials and hybrid-joints was investigated by electrochemical methods indicating an increased corrosion of the Mg alloy in the area of the Al/Mg-butt weld.

Realization of Al/Mg-Hybrid-Joints by Ultrasound Supported Friction Stir Welding

To realize modern light weight constructions it is more and more necessary to combine the advantages of dissimilar materials. Fusion welding of dissimilar metals is in the most cases difficult or even impossible as a result of different melting points of the materials and the development of undesirable brittle intermetallic phases in the welding zone. This often leads to joint strengths considerable below the tensile strength of the base materials. By using Friction Stir Welding (FSW) as a pressure welding method, it is possible to reduce the development of the intermetallic phases of Al/Mg-joints significantly. But as calculated phase diagrams and high resolution microscopic SEM-investigations have shown it is not feasible to avoid them completely. The intermetallic phases form in the contact area very small continuous layers between the joining partners. On the other side it is known that ultrasonic energy can crack oxide layers. Hence a hybrid welding system at the Institute of Materials Science and Engineering (WKK) at the University of Kaiserslautern was developed called “Ultrasound Supported Friction Stir Welding (US-FSW)” with the aim to shatter the brittle interlayer lines and to scatter fragments in the welding area during the FSW process. Pre-investigations have shown that for US-FSW-joints between Al wrought alloys and Mg cast alloys the strength can be increased up to 30% in comparison to conventional friction stir welds. Currently, further investigations are carried out with joints between AC-48000 and AZ80.

Decreased capacity for sodium export out of Arabidopsis chloroplasts impairs salt tolerance, photosynthesis and plant performance

Salt stress is a widespread phenomenon, limiting plant performance in large areas around the world. Although various types of plant sodium/proton antiporters have been characterized, the physiological function of NHD1 from Arabidopsis thaliana has not been elucidated in detail so far. Here we report that the NHD1-GFP fusion protein localizes to the chloroplast envelope. Heterologous expression of AtNHD1 was sufficient to complement a salt-sensitive Escherichia coli mutant lacking its endogenous sodium/proton exchangers. Transport competence of NHD1 was confirmed using recombinant, highly purified carrier protein reconstituted into proteoliposomes, proving Na(+) /H(+) antiport. In planta NHD1 expression was found to be highest in mature and senescent leaves but was not induced by sodium chloride application. When compared to wild-type controls, nhd1 T-DNA insertion mutants showed decreased biomasses and lower chlorophyll levels after sodium feeding. Interestingly, if grown on sand and supplemented with high sodium chloride, nhd1 mutants exhibited leaf tissue Na(+) levels similar to those of wild-type plants, but the Na(+) content of chloroplasts increased significantly. These high sodium levels in mutant chloroplasts resulted in markedly impaired photosynthetic performance as revealed by a lower quantum yield of photosystem II and increased non-photochemical quenching. Moreover, high Na(+) levels might hamper activity of the plastidic bile acid/sodium symporter family protein 2 (BASS2). The resulting pyruvate deficiency might cause the observed decreased phenylalanine levels in the nhd1 mutants due to lack of precursors.

Shu Tezuka, Joos Heintz, Bart Kuijpers, and Andrés Rojas Paredes Share the 2013 Best Paper Award

The Award Committee – Michael Gnewuch, University of Kaiserslautern, Germany and Friedrich Pillichshammer, Johannes Kepler University, Austria – determined that the following two papers exhibited exceptional merit and therefore awarded the prize to: ShuTezuka for his paper ‘‘On the discrepancy of generalizedNiederreiter sequences’’, which appeared in June–August, 2013. Vol. 29, pp. 240–247. Joos Heintz, Bart Kuijpers, and Andres Rojas Paredes for their paper ‘‘Software engineering and complexity in effective Algebraic Geometry’’, which appeared in February, 2013. Vol. 29, pp. 92–138. The $3000 prize will be divided between the winners. Each author will also receive a plaque.

Microstructural and thermodynamic investigations on friction stir welded Mg/Al-joints

Abstract With friction stir welding it is possible to join light metals in the solid state. However joints between dissimilar metals are a special challenge. At the Institute of Materials Science and Engineering of the University of Kaiserslautern the friction stir weldability of magnesium–aluminium-joints was investigated. For the realization of high strength joints between these materials the knowledge of the developing microstructure in the welding zone is of especially high interest. Therefore, light microscopic and scanning electron microscopic investigations were carried out and the results compared with phase diagrams and phase fractions for the bonding zone which were calculated at Institute of Metallurgy of the University of Clausthal.