Er对AZ91镁合金铸态组织和耐蚀性能的影响

Effect of Erbium Addition on Microstructure and Corrosion Resistance of AZ91 Magnesium Alloy

利用真空电磁感应熔炼炉制备AZ91-XEr(X=0,0.58%,1.14%,1.81%)镁合金,采用静态失重法测试实验合金腐蚀行为,运用金相显微镜(OM)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)等测试手段对腐蚀前后实验合金进行表征,研究Er对实验合金显微组织及耐蚀性能的影响。结果表明,添加Er后合金组织得到细化,合金物相主要由α-Mg、β(Mg17Al12)和Al2Er相组成。随着Er含量增加,β相由粗大的不连续网状变为细小的块状,且Al2Er相数量、尺寸增加。Er可以提高AZ91镁合金的耐蚀性能,当Er含量为1.81%时,实验合金耐蚀性最好。

AZ91-XEr（ x = 0,0.58%, 1.14%, 1.81% ）alloys were prepared by vacuum induction melting process. The corrosion behavior of the experimental alloys was tested by static mass loss method. Microstructures of the alloys containing dif- ferent Er before and after corrosion were characterized by optical microscope （OM） , X-ray diffraction （XRD） and scanning e- lectron microscope（SEM）. The effect of Er addition on microstructure and corrosion resistance of AZ91 magnesium alloy was investigated. The results show that with the addition of Er, the microstructure of the alloy is refined,and the alloy is mainly eompose of α -Mg matrix , [5（Mg17Al12） and M2Er phase. With the increase of Er content, 15（MglTAll2） phase changes from discontinuous bulky retieular to small blocks, and number and size of AI2 Er phase increase. Er can improve the corrosion resistance of AZgl magnesium alloy. When Er content is 1.81% , the alloy corrosion resistance is the best.