AlNiLaCe新型高熵非晶合金的组织结构与电化学腐蚀行为

Microstructure and Electrochemical Corrosion Behavior of Novel AlNiLaCe High Entropy Metallic Glasses

采用电弧熔炼工艺与真空熔炼快淬系统制备了一系列新型AlNiLaCe高熵非晶合金条带,并研究了(AlNi)/(LaCe)含量变化对高熵非晶合金组织结构与电化学腐蚀行为的影响。利用X射线衍射仪(XRD)、差示扫描量热仪(DSC)和显微硬度计分别研究测定了高熵非晶合金的相结构、热稳定性与硬度;借助扫描电子显微镜(SEM)与X射线能谱(EDS)分析仪表征了合金条带的表面形貌与元素分布情况;通过极化曲线(Tafel)考察了高熵非晶合金在3.5%NaCl(质量分数)溶液中的电化学腐蚀行为并通过XRD测定了等原子比AlNiLaCe高熵非晶合金条带的腐蚀产物。结果表明:随着Al含量的增加,AlNiLaCe高熵非晶合金由典型的非晶态结构与含Al的金属间化合物共同组成;合金中(AlNi)含量增多导致其热稳定性与条带硬度逐渐提高,Al_(35)Ni_(35)La_(15)Ce_(15)高熵非晶合金最高硬度(HV_(0.1))为4700 MPa。通过电化学腐蚀试验发现:相比AZ91镁合金,AlNiLaCe系高熵非晶合金的自腐蚀电位更高,腐蚀电流密度比镁合金低1个数量级。

A new kind of AlNiLaCe high entropy metallic glass ribbons(denoted as HE-MG ribbons)were prepared by arc melting and melt spinning.The effects of(AlNi)/(LaCe)ratio on the microstructure and electrochemical corrosion behavior of HE-MG ribbons were studied.The phase structure,thermal stability and hardness of these ribbons were determined by XRD,DSC and Vickers hardness tester.The surface morphology and corresponding element distribution of these ribbons were characterized by SEM and EDS.The electrochemical corrosion behavior of several AlNiLaCe HE-MG ribbons in 3.5wt%NaCl solution was investigated by polarization curve(Tafel),and the corrosion products of Al_(25)Ni_(25)La_(25)Ce_(25) ribbons were tested by XRD.The results show that with the increase of Al content,AlNiLaCe high entropy amorphous alloy ribbons are mainly composed of amorphous phase and Al-rich intermetallic compounds.The increase of(AlNi)content in the alloy ribbons leads to the gradual improvement of their thermal stability and hardness.The maximum hardness(HV0.1)of Al_(35)Ni_(35)La_(15)Ce_(15) high entropy amorphous alloy ribbons is about 4700 MPa.Through electrochemical corrosion experiments,it is found that compared with AZ91 magnesium alloy,the corrosion potential of AlNiLaCe alloy ribbons is higher and the current density is one order of magnitude lower than that of magnesium alloy.