Cavitation Erosion Characteristics of Titanium Alloy Thin Film Prepared by Ion Beam Enhanced Deposition

Abstract

Titanium alloy and titanium alloy film possess potential application in MEMS and microfluidic system used in biological bodies for their special mechanical performance and biocompatibility. In order to explore their cavitation erosion characteristics, titanium alloy thin films were prepared on glass bases by ion beam enhanced deposition method. Cavitation erosion characteristics of titanium thin film were explored by means of ultrasonic vibrator. Comparison with titanium alloy bulk and the effect of cavitation strength on cavitation erosion were also conducted. The initial surface and cavitation erosion topography of titanium alloy thin film and bulk were analyzed by scanning electron microscopy (SEM). The water contact angle was measured by contact angle measurement and corresponding surface energy was calculated. The experimental results show that there is no obvious slippage and deformation along the grain boundary on the surface of the titanium alloy films and bulk. There exists little plastic deformation in titanium alloy films compared with titanium alloy bulk. The four stages of the titanium alloy film cavitation erosion are incubation period, concave formation, delamination, and localized fracture. The eroded area and eroded area loss rate increase with cavitation erosion time increasing. However, the increment of eroded area becomes slow and eroded area loss rate decreases if cavitation erosion time exceeds some threshold. More bubbles can be produced by larger cavitation strength, which makes the collapse pressure increase and the damage on specimen surface become severe. Two-color image processing can be used to analyze surface changes of the materials qualitatively.