摘要
Multi-principal element alloys (MPEAs) have emerged as a promising class of materials due to their attractive physical and mechanical properties. Recent studies have demonstrated that these alloys can achieve exceptional strength-ductility combinations, especially when strengthened through precipitation engineering. With the increasing use of additive manufacturing (AM), further improvements have been realized through the formation of hierarchical microstructures. However, fatigue behavior is critical for structural applications, remains less explored. In this work, we investigate tensile and high cycle fatigue (HCF) performance, respectively, of a dual-precipitation-strengthened Al0.2Co1.5CrFeNi1.5Ti0.3 high-entropy alloy (HEA) fabricated by selective laser melting (SLM). Comprehensive characterization was performed to examine the interplay between AM-induced microstructural features and precipitation behavior, and their combined influence on fatigue mechanisms. The alloy exhibits a notable endurance strength of similar to 0.4 - 0.5 times its ultimate tensile strength (UTS), which is competitive with or superior to many AM structural alloys. The coherent L1(2) precipitates contribute significantly to strengthening under both monotonic and cyclic loading, while the L2(1) precipitates also contributed in resistance to fatigue crack propagation.