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Aufsatz
Characterization of Mechanical Properties, Macroscopic Deformation Behavior, and Microstructure of Functionally Graded 22MnB5 Steel
(2021-03-24)
The focus of this study is on the characterization of the local plastic deformation and failure of functionally graded 22MnB5 plates after hot stamping using an in situ approach. Various forming strategies at elevated temperatures are performed using differentially tempered forming tools to locally tailor the microstructure. By controlling the cooling rate, graded as well as martensitic and ferritic–pearlitic microstructures are obtained. Experimental analysis includes evaluation of the material- and geometry-dependent ...
Aufsatz
On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting
(2021-03-10)
Additive manufacturing (AM) processes such as electron beam melting (EBM) are characterized by unprecedented design freedom. Topology optimization and design of the microstructure of metallic materials are enabled by rapid progress in this field. The latter is of highest importance as many applications demand appropriate mechanical as well as functional material properties. For instance, biodegradable implants have to meet mechanical properties of human bone and at the same time guarantee adequate cytocompatibility ...
Aufsatz
On the Influence of Microstructure on the Corrosion Behavior of Fe–Mn–Al–Ni Shape Memory Alloy in 5.0 wt% NaCl Solution
(2020-10-03)
Herein the corrosion behavior of Fe–Mn–Al–Ni shape memory alloys characterized by different microstructures in a 5.0 wt% NaCl solution is investigated. Open circuit potential and potentiodynamic polarisation tests are conducted. Generally, Fe–Mn–Al–Ni shows corrosion properties being similar to pure iron. However, the polarization curves of single crystals indicate the presence of an unstable passive system. The corrosion damage is analyzed by means of optical microscopy and electron microscopy. It is revealed that ...
Aufsatz
Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045
(2021-05-07)
The stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and ...
Aufsatz
Cooling rate as a process parameter in advanced roll forming to tailor microstructure,mechanical and corrosion properties of EN AW 7075 tubes
(2022-12-14)
The effects of solution heat treatment parameters and quench media as a processing tool for tailoring microstructure, mechanical and corrosion properties in roll forming of EN AW 7075 alloy were studied. The highest yield stress and ultimate tensile strength were obtained for the specimens quenched in water, while the air-cooled specimens exhibited inferior mechanical properties. Microstructural analysis of specimens showed that except water-quenched specimens, the parts cooled/quenched in oil, in direct contact with ...
Aufsatz
In-situ full-field deformation analysis of injection-molded microcellular polycarbonate according to foam morphology patterns
(2023-06-02)
Deformation behavior of microcellular foam materials are sensitive to microstructural details. Therefore, the distinctive foam morphology patterns of foam injection-molded Polycarbonate are identified. These morphology patterns are investigated regarding their cell size, distance between cells, cell density, density reduction, homogeneity of cell size distribution, sphericity of cells and cell volume. Consequently, the predefined foam morphologies, the resulting modulus of elasticity and the elongation at break are ...
Aufsatz
On the low-cycle fatigue behavior of thermo-mechanically processed high-strength aluminum alloys
(2021)
In the present work low-cycle fatigue experiments were carried out on thermo-mechanically processed AA6082 and AA7075 sheets to evaluate mechanical properties under cyclic loading. Different cooling rates imposed by use of tempered forming tools after solutionizing and subsequent aging treatment led to the formation of precipitates with differing sizes and morphologies. Specimens thermo-mechanically processed in tools with temperatures of 24 °C and 200 °C showed superior mechanical properties under both monotonic and ...
Aufsatz
Partial purification of tannase enzyme produced by Bacillus licheniformis isolated from local soils
(2023-12-28)
Tannase is an enzyme that causes hydrolysis of a group of tannins (gallo-tannins) to gallic acid and glucose. This enzyme is of importance due to its numerous applications in many fields, such as in the food industry by enhancing tea and coffee flavour and improving the quality of fruit juices rich in tannins. Gallic acid is applied in the drug industry, and production of antioxidants is used in the oil industry. In this study, Tannase was produced by locally isolated Bacillus licheniformis using spent tea as substrate ...
Aufsatz
Who Plays the Role? Is it Millennial Farmers? A Case Study in Pagelaran District, Malang Regency, Indonesia
(2023-12-28)
The Ministry of Agriculture is initiating the birth of millennial farmers as an alternative to accelerate farmer regeneration, including through the Youth Entrepreneurship and Employment Support Services Programme (YESS Programme). After seeing the background of youth unemployment, one of the issues that can be identified in the stakeholder analysis of the YESS program is the effectiveness of the program in addressing youth unemployment. Research related to stakeholder role analysis has been widely used for various ...
Aufsatz
Association between metabolic and immunological changes during the transition period of dual-purpose cows in the Veracruz tropic, Mexico
(2023-12-30)
The objective of this study was to identify changes and associations in body condition score (BCS), serum glucose and β-hydroxybutyrate (BHB) concentrations, and white blood cell populations in dual-purpose cows during the transition period in the Veracruz tropic. BCS was evaluated and blood samples were taken weekly to determine white blood cell populations, serum glucose and BHB concentrations of 30 multiparous dual-cows (Bos taurus × Bos indicus) from 3 weeks before the expected date of calving to 3 weeks postpartum. ...