Development of a NiCoCrMo0.2 medium-entropy alloy via laser additive manufacturing for application in agitator blades of acid reactors

To enhance the service life of agitator blades in phosphoric acid reactors, the NiCoCrMo 0.2 medium-entropy alloy (Mo 0.2 MEA) was designed using the cluster-plus-glue-atom model. The microstructure and erosion resistance of Mo 0.2 MEA were analyzed, revealing a composition of FCC solid-solution dendrites with small μ phases. Mo 0.2 MEA exhibits a higher microhardness (256.4 HV 0.2 ) compared to its Mo-free counterpart. Additionally, the lowest I corr value and largest impedance radius indicate superior corrosion resistance relative to 904L steel, attributed to a dense and stable passive film of MoO 3 and Cr 2 O 3 . The erosion resistance of Mo 0.2 MEA, assessed by cumulative mass loss, is double that of 904L stainless steel. Furthermore, the Stacking-fault energy of Mo 0 MEA (∼−105.7 mJ/m 2 ) is lower than that of Mo 0.2 MEA (∼−85.91 mJ/m 2 ) and 904L (∼251.2 mJ/m 2 ), suggesting greater plastic deformation capability in Mo 0 MEA. These findings offer a new approach for developing anti-erosion medium-entropy alloys through high-entropy alloying and laser additive manufacturing, guided by the cluster-plus-glue-atom model.