*Article* **A Lightweight AlCrTiV0.5Cu***x* **High-Entropy Alloy with Excellent Corrosion Resistance**

**Zhen Peng 1,\*, Baowei Li 1, Zaibin Luo 1, Xuefei Chen 1, Yao Tang 2, Guannan Yang 3,\* and Pan Gong <sup>4</sup>**


**Abstract:** Lightweight high-entropy alloys (HEAs) are a new class of low-density, high strengthto-weight ratio metallic structural material. Understanding their corrosion behavior is crucial for designing microstructures for their practical applications. This work investigates the electrochemical corrosion behavior of lightweight HEAs AlCrTiV0.5Cu*<sup>x</sup>* (*x* = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) in a 0.6 M NaCl solution. These HEAs were produced by vacuum arc melting. In contrast to 304L stainless steel, all of the alloys exhibited lower current density levels caused by self-corrosion, with AlCrTiV0.5 demonstrating the highest corrosion resistance (0.131 μA/cm2). Corrosion resistance decreased along with the content of copper because copper segregation accelerated local corrosion throughout the alloy.

**Keywords:** corrosion resistance; high entropy alloys; microstructure; lightweight
