Effect of surface microstructure spacing on the cavitation erosion process of stainless steel

Fabricating microstructures on the surface is an innovative method to mitigate cavitation erosion (CE), but there are few studies focus on the effects and mechanisms of microstructure spacing on CE performance. This study has prepared a regular dot array-shaped microstructure with different spacings on the surface of samples. The CE experiments were carried out on both the microstructured samples and smooth samples through a magnetostrictive-vibration cavitation facility. Mass loss measurement and microscopic morphology were utilized to reveal CE characteristics. Numerical simulation was used to study the parameters of the flow field. The results clearly show that the microstructure spacing of 0.25 mm, 0.50 mm, and 1.00 mm samples can improve CE resistance. On these microstructured surfaces, the volume fraction of vapor is reduced and the bubbles move away from it. However, when the microstructure spacing enlarges to 1.50 mm, the damage inside the microstructure groove increases, which will reduce the CE resistance of the materials. As the spacing increases, the volume fraction of vapor on the sample surfaces will increase, and the bubbles in the microstructure groove will congregate, resulting in increasing damage. The research provides the dimensional basis for designing cavitation- resistant surface microstructures.