Thermal fatigue behavior of Mg–9Al–Zn alloy with biomimetic strengthening units processed by laser surface remelting

• Biomimetic laser treatment was used to treat the surface of Mg–9Al–Zn Alloy.
• The scanning strategy was inspired by the supporting veins on dragonfly wing.
• Thermal fatigue test was conducted to study fatigue resistance of the surface.
• Cracking behavior on the sample surface was compared to that on dragonfly wing.

Pulsed Nd:YAG laser was used to treat the surface of a magnesium alloy to improve the thermal fatigue resistance. The average grain size of the as-received material was reduced to ~3 μm and moreover β-Mg17Al12 was precipitated in different forms. In addition, high density dislocation was acquired. The treated zone could efficiently prevent cracking on the sample surface. The crack growth was curbed within the treated zone and the microhardness increased by 80%. This enhancement was ascribed to the modified microstructural characteristics of the treated surface.