Investigations of Large Grained Samples — Examples

Abstract

The single grain measuring and evaluation technique allows the investigation of individual grains embedded in their polycrystalline matrix. Using X-ray diffraction grains at the surface of the material were analysed with a local resolution of O ≈ 50 µm. This way the stress distribution over the coarse grain zone and the transition zone of a welding was investigated. Applying neutron diffraction grain sizes of O > 1 mm could be studied. For investigating the inhomogeneous elastic and plastic deformation behaviour of crystallites in the polycrystalline matrix grain clusters were analysed at different applied stress levels. Significant variations from grain to grain are found. The results concerning the elastic deformation are compared to the macroscopic deformations and to the deformation states calculated for free single crystals so indicating the influencing factors on the crystallite-crystallite interaction in the polycrystal. The plastic deformation state was analysed by rocking curves in different crystal directions which allowed the calculation of the anisotropy of the plastic deformation. Moreover, the inhomogeneity of the onset and the development of the plastic deformation as function of the external load was followed.