Röntgenographische Spannungsanalyse in einzelnen Kristalliten – Mess‐ und Auswerteroutinen sowie Einflussgrößen

X‐ray Stress Analysis in Single Crystallites – Measuring Method and Analysis Routines The X‐ray stress analysis in single grains of a coarse grained material can be performed by using the single crystal method. In this work theoretical basics and measuring algorithms for the single crystal method are presented. Test measurements on an iron‐silicon alloy were carried out for different wave lengths and for different lattice planes. It is demonstrated that the Mo‐Kα radiation is well suited for the X‐ray stress analysis in single grains of the material investigated.     

Nachhaltigkeitsaspekte unter der Lupe – Ökobilanzen im Gebäudevergleich

Checking out sustainability aspects – life cycle assessments in building comparisons The topic of life cycle assessments at building level plays an increasing role in environmental and socio‐economic terms. This article analyzes the aspect of climate protection in the context of sustainability assessments of buildings. A summary of five life cycle assessment studies accepted by experts (LCEE, RUB, KÖNIG, FIW, STEINBEIS) is given with reference to building‐related life cycle assessments. In particular, the assumptions and framework conditions made in these studies and their effects on the results are assessed. Similarities as well as essential differences of the individual studies are shown in form of a comparative analysis.     

Korngrenzenphasen in Schmelzlötverbindungen,Bildung – Schmelzen – Zusammensetzung

At the thermal solidification of metallic and non metallic melts with technical purity the thermal solidification of polycristalline substances is carried out under beginning of the corresponding grains and the beginning of a grain boundary phase between these grains. For the examination of the kinetics of melting thermally the authors used the gradual heating of eutectic SnPb solder pearls in an oxygen free heat up liquid. The developed method for the ultrasound supported dispersion of solid solder metals in an oxygen free heat up liquid was used for the separated thermal melt of the grain boundary phase and the grains.     

Berechnung von Röntgenreflexen für polykristallines Titan unter dem Einfluß von Stickstoffgradienten und Eigenspannungen

Calculation of X-ray reflections of polycrystalline Titanium under the influence of a nitrogen gradient and residual stresses In the present paper a procedure is shown for the calculation of x-ray reflections from a crystalline solid, in which a concentration gradient as well as planar surface residual stresses exist. The (004)-reflection of nitrided titanium with residual stresses serves as an example. The profiles and positions of the (004)-reflections are calculated for a residual stress measurement according to the ω-procedure. The calculated results show that a concentration gradient broadens the reflection profile while homogeneous residual stresses shift the position of the reflection. Since the position of the reflection is only negligibly altered by a concentration gradient, a separation of both influences from the analysis of the diffractogram is possible.     

Röntgenographische Untersuchung von Spannungszuständen in Werkstoffen Teil IV. Fortsetzung von Matwiss. und Werkstofftechn. Heft 3/1995, S. 148–160, Heft 4/1995, S. 199–216 und Heft 9/1996, S. 426–437

X-Ray Investigation of Stress States in Materials X-ray stress analyses of crystalline or partially crystalline materials are based on the determination of elastic lattice strains which are converted to stresses by means of theory of elasticity. The development of the sin²Ψ-method of X-ray stress analysis and of diffractometers substituting film chambers during the 1960s initiated an enormous progress in X-ray stress analysis during the following three decades both in respect of the knowledge of the underlying principles and in respect of the practical application. This report sketches the historical development of X-ray stress analyses and describes the actual state of the art of this important tool for materials science and engineering. Besides some important elements of X-ray physics and theory of elasticity, experimental aspects of practical applications are outlined. Standard measuring procedures and special measuring problems are described and hints for practical solutions are given. In particular, examples of destructive and non-destructive depth profiling of residual stresses of residual stress analyses in thin coatings, in multilayer structures of thin coatings and in chemically graded coatings, of residual stress analyses in presence of textures, of residual and loading stress analyses in heterogeneous materials, in coarse grained, and in single crystalline materials are presented. The methods established up to now are explained and possible future developments are pointed out.     

Röntgenographische Untersuchung von Spannungszuständen in Werkstoffen. Teil III. Fortsetzung von Matwiss. und Werkstofftechn. Heft 3/1995, S. 148–160 und Heft 4/1995, S. 199–216

X-Ray Investigation of Stress States in materials X-ray stress analyses on crystalline or partially crystalline materials are based on the determination of elastic lattice strains which are converted to stresses by means of theory of elasticity. The development of the sin²Ψ-method of X-ray stress analysis and of diffractometers substituting film chambers during the 1960s initiated an enormcus progress in X-ray stress analysis during the following three decades both in respect of the knowledge of the underlying principles and in respect of the practical application This report sketches the historical development of X-ray stress analyses and describes the actual state of the art of this important tool for materials science and engineering. Besides some important elements of X-ray physics and theory of elasticity, experimental aspects of practical applications are outlined. Standard measuring procedures and special measuring problems are described and hints for practical solutions are given. In particular, examples of destructive and non-destructive depth profiling of residual stresses, of residual stress analyses in thin coatings, in multilayer structures of thin coatings and in chemically graded coatings, of residual stress analyses in presence of textures, of residual and loading stress analyses in heterogeneous materials, in coarse grained, and in single crystalline materials are presented. The methods established up to now are explained and possible future developments are pointed out.     

Röntgenographische Untersuchung von Spannungszuständen in Werkstoffen. Teil II. Fortsetzung von Matwiss. und Werktoffechn. Heft 3/1995, S. 148–160

X-ray Investigation of Stress States in Materials X-ray stress analyses on crystalline or partially crystalline materials are based on the determination of elastic lattice strains which are converted to stresses by means of theory of elasticity. The development of the sin² ψ-method of X-ray stress analysis and of diffractometers substituting film chambers during the 1960s initiated an enormous progress in X-ray stress analysis during the following three decades both in respect of the knowledge of the underlying principles and in respect of the practical application. This report sketches the historical development of X-ray stress analyses and describes the actual state of the art of this important tool for materials science and engineering. Besides some important elements of X-ray physics and theory of elasticity, experimental aspects of practical applications are outlined. Standard measuring procedures and special measuring problems are described, and hints for practical solutions are given. In particular, examples of destructive and non-destructive depth profiling of residual stresses, of residual stress analyses in thin coatings, in multilayer structures of thin coatings and in chemically graded coatings, of residual stress analyses in presence of textures, of residual and loading stress analyses in heterogeneous materials, in coarse grained, and in single crystalline materials are presented. The methods established up to now are explained and possible future developments are pointed out.     

Röntgenröhren in der Medizintechnik

X‐Ray Tubes in Medical Imaging Applications The application of X‐rays in medical diagnostics has become an essential element in everyday life. Every hospital or imaging center uses X‐ray radiation to get an insight into the human body within shortest time. The technology which is used to take an image of the mandible or to create a full body scan of an emergency patient by computer tomography within a few seconds is the same. This article describes shortly the history of the invention of X‐rays. The creation of X‐rays is explained by a simple schematic. The relevance and function of the cathode to create free electrons is very important. The evolution form simple thermal filaments to electron field emitters is described. The innovation of liquid metal bearings is also essential to realize high power X‐ray tubes by effectively removing the heat from the anode. After a short excursion to the medical applications of X‐Ray imaging a completely new approach of X‐ray source is described.     

Quantitative Röntgenfluoreszenzanalyse elektronenstrahlerschmolzener Zirkonium-Vanadium-Legierungen

Quantitative Spectral Analysis of Electron Beam Melted Zr V Alloys by X-Rays . In order to analyze electron beam melted Zirkonium Vanadium alloys there has been elaborated a method of X-ray analysis for quick and simple measurement of the Vanadium content. The experimental parameters have been predetermined as theoretically possible. By certain experiments the influence of different heat treatment conditions on the results of the analysis has been checked. Alloys with an under eutectoidal content of Vanadium may be analyzed by x-raying massive specimens, when care is taken for a useful heat treatment of the samples. The larger unregular precipitations of the ZrV₂ phase in over eutectoidal alloys cause a wide spread divergence of the measured quantities. Therefore the alloys should be pounded by a very fine diamond file and the chips mixing them with stearin compresses to tablets. Then it will be possible to suppress the influence of size and distribution of the precipitations. The useful size of the powdery grains can be figured out by the relations between absorption conditions and diameters of the ZrV₂ phase.     

Flussmittelfreies Hartlöten unter reaktiver Prozessgasatmosphäre – ein alternatives Verfahren zum Fügen von Aluminiumwerkstoffen

Flux‐free brazing under reactive process gas atmosphere – an alternative process for joining of aluminium materials Due to the high affinity of aluminium towards oxygen, joining of aluminium materials has ever been a challenge. In particular the efficiency of the process and the abandonment of fluxes during controlled atmosphere brazing have been within the focus of current research projects. The specific addition of reactive gases to the inert process gas atmosphere offers a suitable possibility of aluminium brazing without the use of fluxes. Under the application of hydrogen chloride the activation of the brazing and the workpiece surfaces is to be initiated, thus leading to dissolving the oxide layers. Moreover, the strongly reducing gas silane is used, which specifically removes oxygen and water residuals from the controlled atmosphere. Through a suitable controlled atmosphere brazing process the combination of both, reductive and activating additions, is to be used and tested upon their influence on the gas mixtures and materials used [1–5].