Inhaltszusammenfassung

To analyze interactions between single steps of process chains, variations in material properties, especially the near-surface microstructure and the resulting mechanical properties, specimens with tension screw geometry were machined with five different typical process chains. The resulting microstructures were characterized with light optical and scanning electron microscopy, microhardness measurements as well as X-rays. The different process chains and their parameters lead to different de...To analyze interactions between single steps of process chains, variations in material properties, especially the near-surface microstructure and the resulting mechanical properties, specimens with tension screw geometry were machined with five different typical process chains. The resulting microstructures were characterized with light optical and scanning electron microscopy, microhardness measurements as well as X-rays. The different process chains and their parameters lead to different developments of the microstructure and the resulting residual stresses. The particular process chain influences the surface integrity and consequently the fatigue behavior in a characteristic manner. The plastic strain amplitude as well as high precision temperature and electrical resistance measurements can be used to evaluate the fatigue properties of specimens with tension screw geometry. The development of the temperature provides substantial information with respect to cyclic load dependent changes in the microstructure. The load- and cycle-dependent change of the electrical resistance is a function of the s ecific electrical resistance, which is directly influenced by the defect structure and defect density of the material. Areas and process chains critical in respect to fatigue can be reliably identified. The measured values can be used as input data for the physically based fatigue life calculation method ?PHYBAL? with a very limited number of specimens. Even though the geometry is more complex than a standard fatigue specimen, the calculated lifetimes are in a very good accordance with the conventionally determined S-N curves.» weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Materialwissenschaft

DDC Sachgruppe:
Ingenieurwissenschaften