A novel method for radial hydride analysis in zirconium alloys: HAPPy

Whilst substantial progress has been made in understanding the influence that hydrides have on the mechanical properties of zirconium alloys, there is currently an urgent need for a transparent, reproducible image analysis workflow for their characterisation. In this study, an open-source software package for the analysis of hydride networks, HAPPy (Hydride Analysis Package in Python), is introduced to calculate the radial hydride fraction (RHF) and mean hydride length, as well as characterising the connectivity of the microstructure both quantitatively and qualitatively. In this study, we used the Hough line transform to calculate the orientation distribution of the hydride segments within a micrograph, and its projection on to the radial direction is used to determine the RHF. The proposed methodology is validated, and its robustness is demonstrated over a wide range of microstructures. The image processing prior to analysis as well as the projection method used has been shown to have a significant influence on the calculated RHF, highlighting the need for standardized image analysis workflows to facilitate accurate comparisons and correlations across different studies in the literature. Finally, this paper introduces a new damage susceptibility parameter termed the branch length fraction, which can be used in conjunction with a path of lowest cost algorithm to visualise the most plausible crack path as well as the connectivity evolution over an entire micrograph. [Display omitted]