Corrosion and stress corrosion cracking (SCC) are recognized as the most common destructive failure mechanisms of engineering components across various industries. The synergistic effect of mechanical loading and aggressive environments reduces the degradation resistance of materials, leading to the initiation of cracks and premature failures, which can result in catastrophic incidents. The intrinsic multiscale nature of these two mechanisms and their interaction emphasizes the complexity of assessing their effects on material and component performance. Understanding corrosion and SCC across scales is crucial for predicting the durability of materials and designing more resistant materials for industrial applications. Computational modeling has emerged as an effective approach for evaluating the degradation resistance of engineering materials, serving as a valuable tool in designing components that prevent such failures. The phase-field method has become a promising technique for assessing environmentally assisted damage. This method implicitly tracks the evolution of the material-environment interface and naturally accounts for the combined action between the environment and mechanical loading in driving the material degradation. It effectively overcomes this long-standing obstacle of simulating environmentally assisted damage, especially at the different interacting time scales. These advancements in mechanistic corrosion modeling have enabled the accurate representation of phenomena, such as pit growth, pit-to-crack transition, and crack propagation in arbitrary domains, without requiring special treatments or ad hoc criteria. This talk summarizes recent progress in phase-field modeling of corrosion damage, including localized, trans- and inter-granular corrosion, and stress corrosion cracking in traditional engineering materials [1] and biodegradable Mg alloys [2] at different length scales, from the microstructural level to the macroscopic scale. Several 2D and 3D boundary value problems of particular significance are explored to demonstrate the predictive capabilities of the phase-field frameworks developed. The findings and methodologies presented enhance the ability to anticipate corrosion behavior in various materials and provide a cost-effective way for tailoring more corrosion-resistant materials. The talk also outlines opportunities for further advancements in the field.