軋制對Mg-Al-Pb-La鎂合金腐蝕電化學行為的影響

軋制對Mg-Al-Pb-La鎂合金腐蝕電化學行為的影響Effect of rolling on electrochemical corrosion behavior of Mg-Al-Pb-La alloy

采用熔煉鑄造和塑性變形方法制備Mg-Al-Pb-La鎂合金。采用掃描電鏡和X射線衍射等方法研究軋制對Mg-Al-Pb-La鎂合金顯微組織的影響，采用動電位極化和恒電流放電等方法研究軋制對Mg-Al-Pb-La鎂合金腐蝕電化學行為的影響。結果表明：軋制使Mg-Al-Pb-La鎂合金的晶粒細化、第二相破碎、再結晶程度降低、Mg-Al-Pb-La鎂合金的放電活性增強、耐蝕性變差和陽極效率降低；當軋制變形量為40%時，鎂合金的綜合放電性能優(yōu)良，在電流密度180 mA/cm2下平均放電電位和陽極效率分別為-1.749 V (vs SCE)和(82.9±0.2)%。

The Mg-Al-Pb-La alloy was prepared by melting and casting as well as plastic deformation. The effect of rolling on microstructure of Mg-Al-Pb-La alloy was investigated by scanning electron microscopy, X-ray diffractometry and electron backscatter diffractometry. The effect of rolling on electrochemical corrosion behavior was studied by potentiodynamic polarization and galvanostatic measurements. The results show that the discharge activity of the rolled Mg-Al-Pb-La alloys is enhanced. It is related with the refined grains, fractured and homogeneously distributed second phases, and the lowered recrystallization degree of Mg-Al-Pb-La alloy after hot rolling. The Mg-Al-Pb-La alloy with critical rolling deformation of 40% exhibits good discharge performance with strong discharge activity (-1.749 V (vs SCE)) and a relatively high anodic efficiency of (82.9±0.2)%, while the alloy under rolling deformation of 60% exhibits the worst corrosion resistance whose corrosion current density is (49.8±1.3) μA/cm2.

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