Insight Into The Backbone Structure And Corrosion Properties Of Al-Ni-RE Amorphous Alloys On Solute Elements Addition

Al-based metallic glasses exhibit extremely good corrosion resistance combined with high strength and have potential application as structural and function material. In Al-based metallic glasses, Al-TM-RE metallic glasses are more famous for their excellent glass forming ability and properties. Under the corrosion condition, the change the structure of the metallic glasses has large influence on the corrosion resistance ability. There still have some unresolved problems such as the phase seperation phenomenon during the corrosion process and the effect of evolution of clusters on the corrosion resistance ability of Al-based metallic glasses. This research mainly choose the Al-Ni-RE amorphous alloys produced by single-roller spinning as the objects. The structure and the situation of the stress are analyzed in the good conductivity solution and 3.5wt.% NaCl solution by the means of elements addition and annealing treatment. In addition, the molecular dynamics simulation was also adopted to further explore the structure of the amorphous alloys and tends to discovered the role of element addition on the structure and the corrosion resistance of Al-based metallic glasses.The corrosion-induced crystallization of A194-xNixGd6 (x= 6 and 10) metallic glasses as well as phase separation, oxidation and cracking in good conductivity solution has been investigated by various techniques. The transmission electronic microscope (TEM) result reveals that crystalline intermetallic and oxides present on the electrochemical thinned hole edge, and the phase separation occurs in the matrix of the as-spun ribbons with Rc= 29.3 m/s. Though the mixing enthalpy between the elements in Al-Ni-Gd metallic glasses are all negative, but according to our physical model, we find the phase seperation is possible to occur when the composition is located in the region where the atoms can have a ordered structure. In addition, the bending and cracking of the samples occur after corrosion. The influence of Ni content on the phase separation, bending and cracking can be explained by the fact that the percolation of the backbone clusters in the amorphous alloy melts and glasses is enhanced by increasing cNi.Besides, high cooling rate is also benefit to the percolation of backbone clusters, this will lead to the wheel surface and free surface have different structural. After polarization, the bending and cracking will happen.Atomic cluster evolution and corrosion behavior of Al84Ni10Gd6-xYx (x= 0,2,4 and 6) metallic glasses were investigated using experimental methods and ab initio molecular dynamic simulations. The shoulder peak area in XRD patterns, enthalpy of second and third crystallization and population of <0 3 6 0> Ni-centered clusters increase with increasing CY, but the onset temperature and enthalpy of first crystallization decrease simultaneously. Y substitution as well as annealing treatment can aggravate metastable pitting and induce a thicker alumina film during polarization, which can be explained by the segregation of Ni-centered clusters and orderization of Al-rich clusters.