Cavitation Peening: A Review

Abstract

The most popular surface modification technology used to enhance the mechanical properties of metallic materials is shot peening. Shot peening improves fatigue life and strength by introducing local plastic deformation pits. However, the pits increase surface roughness, which is a disadvantage for fatigue properties. Recently, cavitation peening, in which cavitation bubble collapse impacts are used, has been developed as an advanced surface modification technology. The advantage of cavitation peening is the lesser increase in surface roughness compared with shot peening, as no solid collisions occur in cavitation peening. In conventional cavitation peening, cavitation is generated by injecting a high-speed water jet into water. However, cavitation peening is different from water jet peening, in which water column impacts are used. In the present review, to avoid confusing cavitation peening and water jet peening, fundamentals and mechanisms of cavitation peening are described in comparison to water jet peening, and the effects and applications of cavitation peening are reviewed compared with the other peening methods.

Luminescence intensity of vortex cavitation in a Venturi tube changing with cavitation number

“…Cavitation in fluid machineries, i.e., hydrodynamic cavitation, has a severe impact on bubble collapse, and cavitation causes severe erosion in hydraulic components, such as pumps [1] , [2] and valves [3] . However, the impact can be utilized for mechanical surface enhancement to enhance material properties, such as fatigue strength, in the same way as shot peening [4] , [5] , and this is called “cavitation peening” [6] . Through research on cavitation damage and cavitation peening, Soyama et al found that vortex cavitation, as shown in Fig.…”

“…It is different from the target vortex, which is closely related to a turbulent eddy. Although the vortex structure of cavitating flow is important in cavitation peening [4] , [5] , [6] , [67] , there is significant misunderstanding of the vortex flow around the submerged water jet [68] , [69] , [70] , and a spherical bubble in shear flow was assumed in the simulation [71] , [72] .…”

Effect of compressive residual stress introduced by cavitation peening and shot peening on the improvement of fatigue strength of stainless steel

“…However, cavitation bubbles, which are used in cavitation peening, form a cloud consisting of small tiny bubbles and the underlying shapes are longitudinal vortices (Soyama et al (1995)). Note that a figure in certain studies showed that the vortex cavitation in the shear layer directly produces a ring region, but this is incorrect (Soyama, 2020b). As Reisman et al (1998) has pointed out, the shock wave induced by cloud cavitation is larger than that due to single bubble cavitation.…”

Effect of Cavitation Peening on Fatigue Properties in Friction Stir Welded Aluminum Alloy AA5754

“…When an impact passing through metallic material was measured by a polyvinylidene fluoride (PVDF) sensor, which was developed to measure cavitation impacts [44,45], the impact produced by laser cavitation in submerged laser peening was larger than that of laser ablation [43]. Cavitation impact can be utilized for mechanical surface treatment, and peening using cavitation impacts are referred to as cavitation peening [46,47]. Cavitation peening might be applicable to improve the fatigue properties of FSWed metals.…”

“…It has been reported that the fatigue strength of stainless steel treated by cavitation peening is better than that of shot peening, water jet peening, and submerged laser peening [43,50]. As mentioned above, a high-speed submerged water jet, i.e., a cavitating jet in water, has been used for conventional cavitation peening [47]. Moreover, a cavitating jet in air was successfully realized by injecting a high-speed water jet into a low-speed water jet, which was injected into air without a water-filled chamber [51,52], and an improvement in fatigue strength of stainless steel using a cavitating jet in air has been reported [53].…”