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Aufsatz
Parameter identification of crack-like notches in aluminum plates based on strain gauge data
(2020-12-31)
The identification of crack parameters and stress intensity factors in aluminum plates under tensile loading is in the focus of the presented research. In this regard, data of strain gauges, distributed along the edges of the samples, are interpreted. In the experiments, slit-shaped notches take the role of cracks located in the interior of the specimens. Their positions, inclinations and lengths as well as the magnitudes of external loadings are identified solving the inverse problems of cracked plates and associated ...
Aufsatz
Quenching of High Entropy Alloys after Annealing
(2020)
The effect of cooling rate after annealing at 900 °C on the microstructure and hardness of high entropy alloys was investigated using two typical samples with the chemical composition of Co₁₆Cr₁₄.₅Fe₂₉Mn₁₁.₅Ni₂₉ and Co₁₁.₅Cr₇Fe₂₇Mn₂₇Ni₂₇(Nb₀.₀₈C₀.₅) (at%). The microstructural characterisation and hardness measurements were carried out by optical microscopy, scanning electron microscopy, wavelength-dispersive X-ray spectroscopy, electron back scattered diffraction, X-ray diffraction technique and Vickers hardness ...
Aufsatz
On the reliability of residual stress measurements in unidirectional carbon fibre reinforced epoxy composites
(2021-03-03)
The present work introduces a novel methodology to analyse non-uniform residual stresses in composite materials. For robust determination of stresses in complex structures made of different layers, it is first necessary to prove that residual stress analysis in a single layer structure can reliably be accomplished. In present work a unidirectional carbon fibre reinforced epoxy is investigated. For residual stress determination, the integral incremental hole drilling method is used. It is revealed that the standard ...
Aufsatz
Comparative investigation of two-dimensional imaging methods and X-ray tomography in the characterization of microstructure
(2017-10-02)
The microstructural features of three different materials have been quantified by means of 2D image analysis and X-ray micro-computer tomography (CT) and the results were compared to determine the reliability of the 2D analysis in the material characterization. The 3D quantification of shrinkage pores and Fe-rich inclusions of an Al-Si-Cu alloy by X-ray tomography was compared with the statistical analysis of the 2D metallographic pictures and a significant difference in the results was found due to the complex ...
Aufsatz
Ti6Al4V lattice structures manufactured by electron beam powder bed fusion - Microstructural and mechanical characterization based on advanced in situ techniques
(2022-12-17)
Powder bed fusion (PBF) processes enable the manufacturing of complex components in a time- and cost-efficient manner. Especially lattice structures are currently focused since they show varying mechanical properties, including different deformation and damage behaviors, which can be used to locally tailor the mechanical behavior. However, the present process-structure-property relationships are highly complex and have to be understood in detail in order to enable an implementation of PBF manufactured lattice structures ...
Aufsatz
On the influence of build orientation on properties of friction stir welded AleSi10Mg parts produced by selective laser melting
(2021-04-06)
Welding and joining of components processed by additive manufacturing (AM) to other AM as well as conventionally produced components is of high importance for industry as this allows to combine advantages of either technique and to produce large-scale structures, respectively. One of the key influencing factors with respect to weldability and mechanical properties of AM components was found to be the inherent microstructural anisotropy of these components. In present work, the precipitation-hardenable Al–Si10Mg was ...
Aufsatz
Effect of Grain Statistics on Micromechanical Modeling: The Example of Additively Manufactured Materials Examined by Electron Backscatter Diffraction
(2020-02-21)
Micromechanical modeling is one of the prominent numerical tools for the prediction of mechanical properties and the understanding of deformation mechanisms of metals. As input parameters, it uses data obtained from microstructure characterization techniques, among which the electron backscatter diffraction (EBSD) technique allows us to understand the nature of microstructural features, that are usually described by statistics. Because of these advantages, the EBSD dataset is widely used for synthetic microstructure ...
Aufsatz
Effect of Tool Temperature on Mechanical Properties and Microstructure of Thermo-Mechanically Processed AA6082 and AA7075 Aluminum Alloys
(2020-06-08)
The present work focuses on the effect of thermo-mechanical processing on the mechanical properties and microstructural evolution of AA6082 and AA7075 aluminum alloys using a novel forming process, i. e. integrating solution heat treatment, hot forming and tool quenching. Different tool temperatures ranging from 24 °C to 350 °C were applied to investigate their influence on mechanical strength and ductility. By using various tool temperatures, this study aims to provide insights needed for tailoring the mechanical ...
Aufsatz
Predicting Flow Stress Behavior of an AA7075 Alloy Using Machine Learning Methods
(2022-09-09)
The present work focuses on the prediction of the hot deformation behavior of thermo-mechanically processed precipitation hardenable aluminum alloy AA7075. The data considered focus on a novel hot forming process at different tool temperatures ranging from 24°C to 350°C to set different cooling rates after solution heat-treatment. Isothermal uniaxial tensile tests in the temperature range of 200°C to 400°C and at strain rates ranging from 0.001 s-¹ to 0.1 s-¹ were carried out on four different material conditions. ...
Aufsatz
Effects of Aging under Stress on Mechanical Properties and Microstructure of EN AW 7075 Alloy
(2021-07-20)
In the present study, microstructural and mechanical properties of EN AW 7075 following stress-aging were assessed. For this purpose, properties of stress-aged samples were compared with values obtained for conventionally aged counterparts. It is revealed that the strength and hardness of EN AW 7075 can be increased by the presence of external stresses during aging. Precipitation kinetics were found to be accelerated. The effects of conventional and stress-aging on the microstructure were analyzed using synergetic ...