Determination of the fatigue fracture planes of Co-Cr-Mo biomedical alloys using electron backscatter diffraction.

Electron backscatter diffraction on a scanning electron microscope has been utilized to acquire crystal orientation information around faceted fatigue cracks in a Co-Cr-Mo alloy for medical implants. The faceted fracture planes are unambiguously determined as {111} planes.

Estimation of dislocation densities in cold rolled Al-Mg-Cu-Mn alloys by combination of yield strength data, EBSD and strength models.

Al-Mg-Cu-Mn alloys have been developed for the packaging industry, in which large cold-working deformations are normally applied that can produce high dislocation densities. In this study, we present a simplified model for the yield strength contributions and apply that to obtain the dislocation densities by determining the orientation factors, which can be obtained via the crystal information of electron backscatter diffraction (EBSD). One alloy subjected to three cold-rolling reductions (10%, 40% and 90%) has been analysed by EBSD, and the density of dislocations are estimated using the strengthening model. This assessment suggests that dislocation densities by the Taylor model are roughly consistent but slightly lower than those determined by transmission electron microscopy.

A simple approach to the determination of the crystallographic orientation: applications and accuracy.

A simple analytical solution for the crystallographic orientation is described. This method is based on one indexed Kikuchi pair in a known zone rather than the corresponding diffraction spots. The accuracy of this method is shown to be better than 0.1 degrees even for cases in which a zone axis deviates by a large angle (e.g. 10 degrees ) from the centre of the beam direction. This approach simplifies experiments because only one pair of Kikuchi lines and a zone axis are needed, and is especially suited when it is difficult or cumbersome to resolve a second pair of Kikuchi lines with sufficient accuracy.