Mechanical properties and corrosion behavior of novel Al-Mg-Zn-Cu-Si lightweight high entropy alloys

Lightweight high entropy alloys (HEAs) have great application potential in automobile and many other fields. Herein, novel low-cost Al35Mg30−xZn30Cu5Six (x = 5,10,15) lightweight high entropy alloys were designed and prepared by electric melting. The microstructures, mechanical properties and corrosion behavior in 3.5 wt% NaCl of the alloys were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS), hardness testing, compressive testing, immersion testing and electrochemical testing. The results show that the as-cast Al35Mg30−xZn30Cu5Six alloys have complex phase structures composed of fcc phase, Al-Mg-Zn phase, Mg2Si phase, Si phase and eutectic phase. Although the structures are complex, the alloys exhibit great compressive strength. With the increase of Si/Mg ratio, the content of Al-Mg-Zn phase and eutectic phase decreases, while the content of fcc phase increases, which has a positive effect on the mechanical properties and corrosion resistance of the alloys.