Measurement and Evaluation of Cavitation Bubble Collapse Pressures

In order to study the relationship between cavitation bubble collapse pressures and deformations on materials, a new technique was developed using a pressure sensor which can measure bubble collapse pressures and surface damage at the detecting area simultaneously. Impact loads occurring in a vibratory device were measured and compared with pit or crater sizes observed with a microscope at an early stage on the surfaces of pure Al, Cu, Fe and Ni. A linear relationship was obtained between impact load and the area of pit or crater. The hardnesses of various metals under impact loads at collapse in cavitation bubbles are about one order larger than those under static loads. Critical impact load necessary to form a pit or crater was found to differ among the materials.