Breaking the trade off between corrosion resistance and fatigue lifetime of the coated Mg alloy through cold spraying submicron-grain Al alloy coatings

•Fully dense Al and AlMgSi alloy coatings with submicron grains were deposited with MFCS.•Considerable compressive residual stress was generated within the coatings.•MFCS Al coated Mg alloy show lower corrosion rate even than the bulk Al alloy.•Simultaneous improvement in corrosion resistance and fatigue lifetime is achieved in AlMgSi coated Mg alloy.