Assessment of Electrochemical and Mechanical Behavior of Hot-Extruded Powders and As-Cast Samples of Al-Ni Alloys

作者：Osorio Wislei R^*; Freitas Emmanuelle S; Spinelli Jose E; Cante Manuel V; Afonso Conrado R M; Garcia Amauri

来源：International Journal of Electrochemical Science, 2012, 7(10): 9946-9971.

• Al-Ni alloy
• Hot Extrusion
• Gas atomization
• Microstructure
• Mechanical properties
• Corrosion resistance

The cellular or dendritic morphologies of the Al-rich matrix as well as the morphology, size, and distribution of the intermetallic particles can affect not only the electrochemical corrosion resistance but also the mechanical strength of Al-Ni alloys. The aim of this work is to analyze the effects of two different powder size (d) ranges (d<45 mu m; 106 mu m<d<180 mu m) of Al-Ni alloy samples prepared by nitrogen gas atomization followed by compaction and hot extrusion consolidation, on the microstructure, corrosion behavior and mechanical properties. The corresponding characteristics and properties of directionally solidified Al-Ni alloy samples (as cast) are also examined. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization techniques and an equivalent circuit analysis were used to evaluate the electrochemical behavior in a 0.5 M NaCl solution at room temperature. It was found that finer microstructure arrays are associated with better electrochemical behavior. This was shown to be intimately associated with fragmented or globular Al3Ni intermetallic particles, which detached from the eutectic mixture reducing the cathode area and interfering in the corrosion action. A combined plot of corrosion and mechanical properties as a function of a representative microstructural parameter is proposed, permitting an appropriate combination of these properties to be designed based on the alloy microstructure.

• 出版日期2012-10