Enhanced corrosion and wear resistances in a precipitate-hardened magnesium alloy by laser surface remelting

Abstract

The corrosion and wear behaviors of materials are usually sensitive to the microstructural features. In the current work, a novel strategy using laser surface remelting (LSR) to modify the surface microstructure of a precipitate-hardened magnesium alloy was proposed to synergistically enhance the corrosion and wear resistances. The dedicated microstructural observations indicated that the surface average grain size was remarkably refined (only ∼2.8 μm) after LSR treatment. Meanwhile, the secondary phases in the modified surface region no longer existed randomly within the grains, but preferred to be regularly located along the grain boundaries with a network pattern. In addition, the surface hardness of the specimens subjected to LSR treatment was also improved. Based on those experimental observations, the possible mechanisms responsible for the synergy of the corrosion and wear performances were proposed and discussed. The current results would open a possibility for obtaining magnesium alloys with high corrosion and wear resistances synergistically, and this strategy may also be applicable to other materials. • The microstructural evolution of AZ80 magnesium alloy has been investigated before and after laser surface remelting process. • The corrosion and wear behavior of the as-received and LSR specimens were compared. • The LSR specimens had better corrosion and wear resistance than AR specimens. • The possible mechanisms responsible for the synergy of the corrosion and wear performances were proposed and discussed.