A method for crystallographic mapping of an alpha‐beta titanium alloy with nanometre resolution using scanning precession electron diffraction and open‐source software libraries

Abstract

AbstractAn approach for the crystallographic mapping of two‐phase alloys on the nanoscale using a combination of scanned precession electron diffraction and open‐source python libraries is introduced in this paper. This method is demonstrated using the example of a two‐phase α/β titanium alloy. The data were recorded using a direct electron detector to collect the patterns, and recently developed algorithms to perform automated indexing and analyse the crystallography from the results. Very high‐quality mapping is achieved at a 3 nm step size. The results show the expected Burgers orientation relationships between the α laths and β matrix, as well as the expected misorientations between α laths. A minor issue was found that one area was affected by 180° ambiguities in indexing occur due to this area being aligned too close to a zone axis of the α with twofold projection symmetry (not present in 3D) in the zero‐order Laue Zone, and this should be avoided in data acquisition in the future. Nevertheless, this study demonstrates a good workflow for the analysis of nanocrystalline two‐ or multi‐phase materials, which will be of widespread use in analysing two‐phase titanium and other systems and how they evolve as a function of thermomechanical treatments.