Mechanical Properties and Corrosion Behavior of Multi-Microalloying Mg Alloys Prepared by Adding AlCoCrFeNi Alloy

In this work, a series of multi-microalloying Mg alloys with a high degradation rate and high strength was prepared by adding AlCoCrFeNi HEA particles to the Mg melt followed by hot extrusion. The microstructure evolution and mechanical properties of the alloys were studied, meanwhile, the corrosion properties were evaluated by immersion weight loss and electrochemical tests. Results indicated that HEA particles in the Mg melt were decomposed and formed the Ni-rich phase, which was distributed uniformly in the Mg matrix. Compared with the pure Mg matrix, the Mg-3 HEA alloy exhibited excellent mechanical properties of the ultimate tensile strength ~ 237 MPa and tensile yield strength ~ 181 MPa, an increased rate of ~ 49.1 and ~ 96.7%, respectively, without sacrificing the elongation. And the ultimate compressive strength (UCS) and compressive yield strength increased by ~ 31.5 and ~ 43% to 392 ± 3 and 103 ± 2 MPa, respectively. Based on theoretical analysis, the high YS of the alloys was mainly attributed to fine-grain strengthening and second phase strengthening. Besides, based on the study of corrosion behavior, it was found that with the increase in HEA particle content, the degradation rate of the composites increased because of the promotion of micro-galvanic corrosion, and the Mg-3 HEA alloy showed a maximum degradation rate of ~ 25.2 mg cm −2 h −1 .