• Schell, Norbert
• Ziegelwanger, Tobias
• Holcova, Jitka
• Meindlhumer, Michael
• Bodner, Sabine C.
• Keckes, Jozef
• Todt, Juraj

Abstract

Cross-sectional gradients of residual stresses, phases, microstructure, composition and mechanical properties within the near-surface<br/>regions of thermo-chemical treated steels are decisive for the balanced mechanical properties of the final products. In this work, a<br/>correlative cross-sectional micro-analytics is introduced to assess those gradients in an exemplary nitrided steel sample to a depth<br/>of ~0.8 mm. Cross-sectional synchrotron X-ray microdiffraction with an energy of 87.1 keV and a spatial resolution of 20 µm was<br/>performed in transmission diffraction geometry. At first, a methodology to evaluate residual stress magnitudes from two-dimensional<br/>X-ray diffraction data is discussed. The data from a ~2.5 mm long sample gauge volume indicate complex residual stresses and<br/>near-surface microstructure gradients with a maximal compressive stress of ~-400 MPa, descending diffraction peak broadening and<br/>variable crystallographic texture. The results correlate well with the complementary analyses of Vickers micro hardness and sample<br/>cross-sectional morphology. In summary, the correlative cross-sectional micro-analytics documents the possibility to determine and<br/>correlate a variety of mechanical, structural, morphological and chemical sample parameters obtained using cutting-edge characterization approaches. The complex experimental data can be further used to adjust and verify numerical and technological models.

Topics

• impedance spectroscopy
• microstructure
• surface
• phase
• x-ray diffraction
• hardness
• texture
• two-dimensional
• nitrided steel