Quasi in-situ study on the slip activation mechanism of high purity tantalum during compress deformation

Abstract

The microstructure evolution is very complex during the processing of tantalum sputtering target for integrated circuits, and the deformation mechanisms for this evolution is still unclear. This work aims to investigate the deformation mechanism in a quasi-in-situ way, particularly the activation of slip systems, lattice rotation, and strain concentration, utilizing the electron backscatter diffraction (EBSD) method. We found that the maximal orientation density increased after the deformation, especially the content of both the {111}<uvw> and {100}<uvw> components increased while the {110}<uvw> orientations decreased after the deformation. The lattice rotation leads to misorientation between grain orientations before and after the deformation, and the misorientation axes seem to be randomly distributed during the deformation. The rotation behavior can be adequately described by the activation of both {110}<111> and {112}<111> slip systems, which were found to have no linear relationship with grain size or grain aspect ratio, but are related to the Schmid factors and strain concentration situations. In particular, the inhomogeneous geometrical necessary dislocations distribution indicates the complicated situation of flow stress, and the slip systems activated with smaller Schmid factors are associated with the local heterogeneous strain concentrations.