Recently deepened insights regarding Mg corrosion and advanced engineering applications of Mg alloys

•Generally accepted understandings of Mg corrosion are summarized.•Deepened insights into corrosion mechanism, alloying effect and environmental influence are presented.•The controversial points today are analysed and clarified based on new evidence.•New applications of Mg alloys are discussed as structural, functional and intelligent materials.•Future research directions are suggested in fundamental understanding to industrial application. This review summarizes recent insights into the Mg corrosion mechanism, clarifies many critical controversial points regarding the Mg corrosion behaviour, and updates some efforts made to extend the industrial application of Mg alloys. Based on the new understandings gained so far, future research directions are also suggested in the review. This review has the following logic. The first section “1. Scope” is a consolidation of the new understandings or developments regarding the Mg corrosion mechanism and the new applications for Mg alloys. It also highlights some key points for the review. The second section “2. Widely accepted knowledge” briefly summarizes the general understanding of Mg corrosion gained so far, which acts as the foundation for the following sections. The third section “3. Recently deepened insights” mainly briefs on some new insights into Mg corrosion phenomena based on recent findings. Different interpretations on the corrosion behaviours are comprehensively discussed in the fourth section “4. Controversial points” and the conclusions are drawn in the subsection “4.5 Clarified points”. Apart from the fundamental understandings, various efforts in the application of Mg alloys are presented in the fifth section “5. New applications”. Following the research tendency as indicated in the review, prioritized research areas are suggested in “6. Future directions”. The review is concluded with “7. Concluding remarks” at last.