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

摘要:

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射线能谱分析仪（EDS）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 wt.% NaCl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含量的增多，AlNiLaCe高熵非晶合金由典型的非晶态衍射峰与含Al的金属间化合物一同组成；合金中(AlNi)含量增多导致其热稳定性与条带硬度逐渐提高，Al35Ni35La15Ce15高熵非晶合金最高硬度为470 HV0.1。通过电化学腐蚀实验发现: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。

Abstract:

A new kind of AlNiLaCe high entropy metallic glasses (denoted as HE-MGs) ribbons were prepared by arc melting and melt spinning. The effects of (AlNi) / (LaCe) ratio on the microstructure and electrochemical corrosion behavior of HE-MGs were studied. The phase structure, thermal stability and hardness of these ribbons were determined by X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Vickers hardness tester. The surface morphology and corresponding element distribution of these ribbons were characterized by scanning electron microscope (SEM) and energy dispersive X-ray spectrum (EDS). The electrochemical corrosion behavior of several AlNiLaCe HE-MGs ribbons in 3.5 wt.% NaCl solution was investigated by polarization curve (Tafel), and the corrosion products of Al25Ni25La25Ce25 ribbons were tested by XRD. The results show that with the increase of Al content, AlNiLaCe high entropy amorphous alloy ribbons are mainly comprised 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 of Al35Ni35La15Ce15 high entropy amorphous alloy ribbons is about 470 HV0.1. 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.