Optimizing broad ion beam polishing of zircaloy-4 for electron backscatter diffraction analysis

To provide useful materials characterization, we must prepare samples well so that we can avoid studying artefacts induced during sample preparation. This motivates us to systematically study our preparation methods. In this work, we focus on improving “broad ion beam” (BIB) polishing through a combination of consideration of the ion-sample interactions and a systematic study of options provided by commonly available broad ion beam milling machines. Our study specifically aims to optimise the preparation of zircaloy-4, which is an alloy of zirconium used in nuclear fuel cladding, and we note that this alloy is difficult to prepare with other sample preparations routes. We optimise BIB polishing to study the microstructure of the zircaloy-4 with electron microscopy based electron backscatter diffraction (EBSD). To conclude our study, we provide recommendations for new users of BIB based polishing methods. •We optimise broad ion beam polishing for metallographic sample preparation.•We vary conditions including time, current, gun angle, voltage, and temperature.•We systematically evaluate changes in surface roughness and EBSD quality.•We provide recommendations for routine polishing of zircaloy-4.