機能性キャビテーション技術で形成される高温・高圧キャビテーションがAl-Cu合金表面に与える影響

抄録

In this study, to improve the efficiency and accuracy of multifunction cavitation (MFC) technology, the dependence of the surface condition, residual stress, and surface roughness on the distance from the water jet nozzle (standoff distance) to the specimen surface were evaluated. When Al–Cu alloy specimens were processed by MFC with a swirl flow nozzle (SFN–MFC), water jet peening (WJP) with an SFN (SFN–WJP), and conventional WJP, erosion at the center of the specimens occurred when the standoff distance was 45 mm and was reduced as the standoff distance was increased. The maximum compressive residual stress was reached at standoff distances of 55, 65, and 45 mm for SFN–MFC, SFN–WJP, and WJP, respectively. In SFN–MFC, at standoff distances of 55 and 60 mm, the cavitation bubbles were in the high-pressure and high-temperature regimes, respectively. These results demonstrate that high-temperature and high-pressure regimes exist in MFC, unlike in conventional WJP technology, and the temperature and pressure in the cavitation bubbles depend on the standoff distance.