Abstract:

The metal components exposed to the high-velocity liquid-solid flow can be rapidly eroded by the accelerated particles. With an excellent combination of strength and toughness, the NiCoCrFeNb_0.45 eutectic high-entropy alloy (EHEA) has emerged as a promising material to resist erosion damage. In this study, the erosion behavior of NiCoCrFeNb_0.45 EHEA in high-velocity multiphase flow is investigated through the coupling analysis of material properties, multiphase flow, and particle-surface impact behavior. The inherent mathematical relationship is discovered between the erosion rates and the impact velocity, impact angle, and test time. The results show that the NiCoCrFeNb_0.45 EHEA has superior erosion resistance than the commonly used machinery materials. The principal material removal mechanism is the formation and brittle fracture of the platelets, accompanied by micro-cutting and ploughing at some oblique angles. The higher work-hardenability of NiCoCrFeNb_0.45 EHEA could mitigate the erosion damage as time proceeds, and this effect becomes more apparent as the impact angle increases. Therefore, the evolution of erosion damage with time varies significantly depending on the impact angle. Based on the test data and computational fluid dynamics (CFD) modeling of the near-wall flow field, a power exponential function relationship between erosion depth and the corresponding impact velocity at various locations on the material surface is established.

Key words: Eutectic high-entropy alloy, Erosion evolution, Multiphase flow, Computational fluid dynamics (CFD) modeling