Effects of Laser Surface Melting on the Mechanical Properties and Corrosion Resistance of Mg-Y-Zn Rare Earth Mg Alloy AITranslate

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Chinese Library Classification Number:TG146.2[金属学及工艺—金属材料]

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Compared with traditional AZ/AM series Mg alloys,rare earth Mg alloys exhibit significantly enhanced high-temperature strength and creep resistance through the addition of elements such as Y and Gd.However,their practical applications remain constrained by insufficient corrosion resistance attributed to high surface reactivity.Surface modification techniques can specifically improve their surface corrosion resistance.Thus,laser surface melting(LSM)treatment was performed on a Mg-9.1Y-1.8Zn(WZ92)rare earth Mg alloy in this study,followed by evaluations of its mechanical properties and corrosion resistance.The results demonstrate that the LSM-treated alloy exhibits significant grain refinement in the melted layer,whose thickness shows a positive correlation with laser power,and the long period stacking ordered(LPSO)phases transform from intergranular network distribution to intragranular directional precipitation.Benefiting from grain refinement strengthening,solid solution strengthening and elimination of brittle eutectic Mg₂₄Y₅ phase,the hardness,strength and ductility of WZ92 alloy are remarkably enhanced.The fine-grained microstructure and homogeneously dispersed LPSO phases within the melted layer synergistically promote the formation of a uniform passive film,thereby reducing localized electrochemical activity and suppressing localized corrosion of the alloy.Concurrently,the reduced content of LPSO phases effectively mitigates micro-galvanic corrosion effects.Alloys laser-treated at 400 W and 500 W demonstrates superior comprehensive corrosion resistance:the former attributed to stable corrosion product film formation,and the latter benefiting from significantly reduced electrochemical activity of the alloy surface.