Papers by Keyword: Special Boundaries

Abstract: By X-ray diffraction and scanning electron microscopy using the method of back-scattered electrons the parameters of the solid solution (the lattice parameter and the mean-square displacement of atoms) and the grain boundary ensembles in the alloy Pd₃Fe with the superstructure L1₂ have been investigated depending on the degree of the long-range atomic order. The relationship between the proportion of the twins Σ3 in the spectrum of special boundaries and the mean-square displacement of atoms was detected.

Abstract: Three different types of austenitic stainless steel (SUS 304, SUS 304L and SUS 316) samples were cold formed in order to investigate the effect of cold forming on the grain boundary structure of the material. SUS 304L and SUS 316 samples were cold rolled, SUS 304 samples were tensile loaded in different manner at room temperature. Electron back scatter diffraction measurements have been carried out in order to obtain information about the boundaries of the treated specimen. The measurements showed that the frequency of the special Σ3n type CSLboundaries was significantly decreased by increasing the deformation of the samples.

Abstract: Solder joints based on Sn-Ag used in electronic systems fail due to thermomechanical fatigue (TMF) damage that develops during service. Grain boundary sliding and/or shear band formation are observed during TMF. Orientation Imaging Microscopy (OIM) was used to study the damage that develops and relate it to slip systems and the grain boundary character that is prevalent in tin. A number of special boundaries form preferentially during solidification, and those with misorientations about a [110] axis, including low angle boundaries, are more likely to slide with thermal cycling. Special boundaries aligned to have large resolved shear stress exhibit large scale sliding, and others with normal stress components exhibit fracture. Damage accumulation depends on the deformation mode, temperature, and initial crystal orientations present in the joint.