Effect of Copper Content on Corrosion Resistance and Glass-formingAbility of Novel AlNiZrCoYSi High Entropy Amorphous Alloy

Abstract:

A new type of high entropy amorphous alloy (denoted as HEAA) ribbons Al_17.5Ni₂₀Zr_17.5Co₂₀Y₂₀Si₅ was prepared by injection in copper mould with arc melting. The effect of Cu content on corrosion resistance of the Al_17.5Ni₂₀Zr_17.5Co₂₀Y₂₀Si₅ HEAA was studied mainly by adding Cu element into the alloy. The glass-forming ability and hardness of the alloy were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and microhardness tester, respectively. The corrosion resistance of these ribbons in 3.5 wt.% NaCl corrosive solution at room temperature were investigated by potentiodynamic polarization curves (Tafel) and Nyquist plots. The results show that four kinds of (AlNiZrCo)_75-xCu_xY₂₀Si₅(x=0, 10, 14, 15) near equiatomic HEAA ribbons present typical amorphous diffraction peaks. The Cu content has little effect on the glass-forming ability of the AlNiZrCoYSi HEAA ribbons, but it will reduce the corrosion resistance. The Vickers microhardness of the above alloys is over 470 HV_0.1. The corrosion resistance of the Al_17.5Ni₂₀Zr_17.5Co₂₀Y₂₀Si₅ HEAA ribbons is the finest. The corrosion potential (E_corr) is -0.248 V, the corrosion-current density (i_corr) is 1.63 μA / cm^₂, and the polarization resistance (R_P) is 24.56 kΩ.cm^₂. This material has demanding application potential to solve the problem of anti-corrosion and wear resistance in harsh marine environment.