Fig. 6: SHAP value analysis of Ni contribution to SCC resistance.
From: XGBoost model for the quantitative assessment of stress corrosion cracking
a Shifting feature impact with increasing Ni. The mean absolute SHAP values for Ni and minor alloying elements (mainly C, H, Si, Mn, Mo, P, S) change markedly at 14.5 wt% Ni, signalling a reduction in their impact on SCC susceptibility. b SHAP values as a function of Ni content illustrate the non-linear relationship between Ni concentration and SCC resistance. A maximum SCC resistance is observed around 40 wt% Ni, whereas SCC susceptibility increases when Ni content exceeds 45 wt%. The SHAP values represent the fluctuations of the Box-Cos transformed values of α. Data points are colour-coded to differentiate samples that failed within(red) and beyond (blue) seven days in boiling MgCl₂, as reported by Copson34 and Staehle et al.35.
