**5. Conclusions**

This study has explored the IGC behavior of a newly designed Al-6Mg alloy with two different cold rolling conditions. It was revealed that the grain size and the continuity of β precipitation play an important role in IGC. The precipitation growth rate and final size of precipitates affect how the grain boundary is covered by β precipitation. At the early period of sensitization, the precipitation growth rate is a crucial factor in IGC. The dislocation density and grain boundary orientation affect the precipitation growth rate. The CR50 alloy has a slightly higher precipitation growth compared to the CR20 alloy because of the high density of dislocations. This results in a higher maximum IGC depth. However, the grain size effect is more dominant when the sensitization time is long enough to cover the grain boundary by anodic β precipitation.

**Author Contributions:** Conceptualization, K.-H.C.; methodology, K.-H.C. and H.-K.L.; software, K.-H.C.; validation, D.-B.L., S.-Y.Y. and N.-S.K.; formal analysis, S.-H.H.; investigation, D.-B.L.; resources, S.-K.K.; data curation, Y.-O.Y.; writing—original draft preparation, K.-H.C.; writing review and editing, B.-H.K. and H.-K.L.; visualization, K.-H.C.; supervision, B.-H.K. and H.-K.L.; project administration, S.-K.K.; funding acquisition, S.-K.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Data sharing not applicable. No new data were created or analyzed in this study. Data sharing is not applicable to this article.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

