Corrosion-Resistance Enhancement of Al-2.5Mg-0.5Cu Alloy by Solidification in Pulsed Magnetic Field

Molten Al-2.5 Mg-0.5 Cu alloy,an advanced water-pipe material,was solidified in the pulsed magnetic field,generated by the lab-built exciting coils energized with pulsed voltage.The influence of the magnetic field on the microstructures,corrosion resistance and mechanical behavior was investigated with X-ray diffraction and scanning electron microscopy.The preliminary results show that the pulsed magnetic field had a major impact.To be specific,the alloy comprised α-Al and Al₂Cu phases. As the magnetic field increased,the volume fraction of Al₂Cu-phase decreased; the corrosion-rate significantly decreased by 55%; and the yield-strength,tensile-strength and elongation-ratio improved.At the strongest pulsed magnetic field available(generated by the highest pulsed voltage of 150 V),the optimized corrosion-rate,yield-strength,tensile-strength and elongation-ratio were 28.2 mm/a,126.3 MPa,168.4 MPa and 7.84%,respectively;and the smallest and shallowest etching-pits indicated that the alloy has the stronger corrosion resistance.