Cavitation Erosion Behavior Research Articles

Cavitation erosion resistance enhancement of the surface modified 2024T351 Al alloy by ultrasonic shot peening

In this study, a novel surface strengthening method for improving cavitation erosion resistance by ultrasonic shot peening (USP) was proposed. Modified 2024T351 aluminium alloy surface layer with the characteristics of refined grains size, increased microhardness and residual compressive stress was prepared by USP treatment. Then the ultrasonic cavitation erosion (UCE) behaviour of the processed 2024T351 Al alloy was investigated. Results indicated that under the combined action of surface hardening and residual compressive stress, the cavitation weight loss of the USP-ed sample was significantly reduced. For the USP-ed 2024T351 Al alloy with an intensity of 0.101mmA, the weight loss after 3 hours' UCE treatment was reduced by 54.2 % compared to the untreated sample. This study also found that the increased surface roughness during shot peening could reduce the cavitation resistance properties. However, the weakening can be avoided by surface finishing. Results indicate that USP is a potential physical strengthening method that can significantly improve the cavitation erosion resistance of metals.

ON MICROSTRUCTURE AND CAVITATION EROSION BEHAVIOR OF MICROWAVE-SYNTHESIZED Ni-Al2O3-BASED COMPOSITE CLADDINGS

In this study, Ni-Al2O3-based composite clads on SS-316 substrates using a microwave irradiation method have been developed. Microwave-processed clads were characterized using various nondestructive techniques to investigate microstructure, phase analysis, porosity assessment and measurement of microhardness. The findings of the microstructural analysis demonstrated the formation of solid, metallurgically bonded and defect-free clads with a thickness of approximately 970[Formula: see text][Formula: see text]m. X-ray diffraction (XRD) phase analysis study confirmed the existence of hard and intermetallic phases in the clad region. Composite clad region exhibited a low porosity value of [Formula: see text]1.3%. The average microhardness of the clad region was 3.63 times that of the substrate region. Further, cavitation erosion (CE) behavior of the developed clads was investigated using vibration CE test rig under various stand-off distances and immersion depths. CE results showed that the composite clads exhibited 6.9 times better erosion resistance than SS-316 substrate. CE resistance increased with an increase in stand-off distance and the depth of immersion.

Cavitation-Erosion behavior of laser cladded Low-Carbon Cobalt-Based alloys on 17-4PH stainless steel

Stellite 728 (C14) with low-carbon and high-molybdenum was used for cavitation resistance application in this research. The specimens were fabricated on the surface of a martensitic precipitation hardening stainless steel called 17-4PH by laser cladding technique. The cavitation erosion behavior in 3.5 wt% NaCl solution is investigated using a 20 kHz vibratory cavitation erosion test machine. The electrochemical corrosion test was also explored to reveal the mechanism of the synergistic effect of cavitation and electrochemical corrosion. The experimental results of the Stellite 728 were compared with those of well-known cavitation-resistant Stellite 6 and wrought Stellite 6B. The surface morphology and microstructure evolution after cavitation were analyzed by means of metallographic microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and 3D optical surface morphometry to explore the cavitation erosion mechanism of the specimens. The experimental results show that the Co-based alloys have better cavitation erosion resistance than 17-4PH, and laser cladded Stellite 728 has better cavitation resistance in 3.5 wt% NaCl solution than laser cladded Stellite 6 and wrought Stellite 6B, owing to the formation of large amounts of Mo-rich intermetallic compound in the alloy.

Why does seawater corrosion significantly inhibit the cavitation erosion damage of nickel-aluminum bronze?

The cavitation erosion (CE) and corrosion behaviors of cast and forged Nickel-aluminum bronzes were studied in deionized water and artificial seawater. Surprisingly, their CE mass losses in seawater were obviously less. Similar to forging process, cavitation load could cause α phase to transform into β phase and dislocation to form in subsurface, which were beneficial to improve mechanical properties. β and κ phases were more easily to be dissolved in corrosion tests. However, cavitation heat changed corrosion mechanism and induced formation of a dense oxide film on surface, which could protect materials covered under it and reduce CE damage.

The role of Ti in cavitation erosion and corrosion behaviours of NAB alloy in 3.5 % NaCl solution

The influence of titanium on the cavitation erosion and corrosion behaviors of a NAB alloy in 3.5 % NaCl solution is investigated using tensile test, mass loss, SEM, Tafel plots, electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The results show that the NAB alloy consists of the α phase, β phase and κ phase, in which titanium will enter the κ phase to form the titanium-rich κ phase. With the increment of titanium, the titanium-rich κ phase changes from mainly distributed at grain boundaries to more dispersed at grain boundaries and inside grains. In the case of high titanium content, the κ phase rich in titanium grows and produces an obvious segregation phenomenon, resulting in a decrease in the mechanical property and corrosion resistance of the substrate. The mass loss experiment shows that the mass loss caused by cavitation erosion decreases with increasing titanium content, and it increases with increasing titanium content when titanium content is over 0.478 %. The electrochemical experiments show that the corrosion resistance of NAB alloy in 3.5 % NaCl solution increases with increasing titanium content and reaches a maximum when titanium content is 0.478 %. The reason for the increased corrosion resistance of a NAB alloy containing titanium in 3.5 % NaCl solution is related to the appearance of TiO2 in the passive film automatically formed on a NAB alloy in air.

Investigations of cavitation erosion and wear resistance of cermet coatings manufactured by HVOF spraying

This work studies the effect of mechanical properties and microstructure on sliding wear and cavitation erosion behaviors of cermet coatings deposited via high velocity oxy-fuel (HVOF) spraying on AZ31 magnesium substrate. Cavitation tests indicated that WC-Co-Cr cermet had superior resistance to cavitation erosion than WC-Cr3C2-Ni, WC-Co coatings, and far better resistance than the AZ31 expressed by the volume material loss 3.74 mm3, 6.99 mm3, 10.30 mm3, and 108.82 mm3, respectively. WC-Co-Cr coating’s erosion mechanism exhibited uniform material removal, which slows the erosion rate. The CoCr binder prevented severe surface pitting and the detachment of the WC-Co-Cr cermet material in massive chunks which was observed for WC-Co and WC-Cr3C2-Ni coatings. Cermet coatings microstructure discontinuities such as pores and ceramic-metallic phase interfaces are the centers of material erosion. No clear correlation between the erosion behavior and mechanical properties of coatings was revealed. Contrary to that, sliding wear results were strongly related to the mechanical properties. The WC-Co-Cr and WC-Co samples exhibited higher hardness and higher values of Young’s modulus than the WC-Cr3C2-Ni one. The generated stresses with lower values of hardness and Young’s modulus for the WC-Cr3C2-Ni sample resulted in a higher wear factor, approx. 1·10−7 mm3·N−1·m−1. For the harder samples, which exhibited higher stiffness (WC-Co-Cr and WC-Co), this type of wear resulted in lower values of the wear factor: 6·10−8 mm3·N−1·m−1 and 9·10−8 mm3·N−1·m−1, respectively. Deposition of the cermet coatings effectively protected the magnesium substrate, which shows low resistance to cavitation erosion and sliding wear when uncoated.

Cavitation Resistance, Microstructure, and Surface Topography of Plasma Nitrided Nimonic 80 A Alloy.

Cavitation erosion of structural materials is a form of wear damage that affects the performance and life of components used in the aerospace, nuclear, and automotive industries, leading to an increase in the frequency of maintenance operations and redesign costs. The cavitation erosion behaviour of the nickel-based superalloy, Nimonic 80 A, was investigated using a piezoceramic crystal vibrator, according to the requirements of ASTM G32-2016. The results showed that plasma nitriding leads to a reduction in the mean erosion penetration depth by approximately ten times and of the erosion rate by the order of six times, compared to the solution heat-treated samples. Typical topographies of cavitation-eroded surfaces show a preferential degradation of the grain boundaries between the γ solid solution phases, of the twins’ boundary, and of the interface between the precipitated particles and the γ solid solution matrix. In the nitrided samples, the cracking initiation is determined by nitride particles, which are hard and brittle. Due to the high mechanical strength of the solid solution γ with the fcc crystal lattice, the appearance of the cavitation surface is uniform, and the fracture has a ductile character.

Effect of Y2O3 addition on the microstructure and liquid LBE cavitation erosion behaviors of Fe-Cr-Al-Ti-C-xY2O3 laser clade coatings

Fe-Cr-Al containing alloys with high resistance to lead-bismuth eutectic (LBE) is considered as one of the candidate materials for the protective coating. But it remains challenge in improving the mechanical properties and resistance to cavitation erosion under the environment of flowing LBE. In this study, Fe-Cr-Al-Ti-C coatings were synthesized with different Y2O3 additions by laser cladding, aiming at improving toughness and cavitation erosion resistance. The results showed that the Fe-Cr-Al-Ti-C coating mainly contained Fe2AlCr and TiC phases, and the addition of Y2O3 led to the formation of Y2TiO5 and Y2Ti2O7, modifying the distribution of TiC. Y2Ti2O7 and Y2TiO5 played a toughening role by purifying impurity oxygen at the grain boundary (GB), and various secondary phases are coordinated. When the addition of Y2O3 is 0.2 wt.%, the cladding coating was well formed, and showing the highest hardness and adhesive strength, which directly affected the resistance to LBE cavitation erosion. When the addition of Y2O3 was more than or equal to 0.8 wt.%, severe segregation of TiC appeared at the GBs, resulting in the decrease of mechanical properties. At 500°C LBE cavitation erosion test, the main damage mechanism of the coating was lamellar spalling. Cracks would initial at the surface under the impact of cavitation erosion and expand into the materials. The addition of Y2O3 reduced the size of crack and improved the LBE cavitation erosion resistance of the cladding coating.

Correlation between microstructure and corrosion and cavitation erosion behaviors of nickel aluminum bronze

The microstructure, corrosion and cavitation erosion (CE) behaviors of the as-cast and four different heat treated nickel aluminum bronzes (NABs) in 3.5 wt.% NaCl solution were investigated. The results show that after annealing, β′ transformed into the eutectoid microstructure, and more κIV precipitated from α. Less eutectoid microstructure and more β′ were obtained after normalizing. The quenched NAB mainly consisted of α and β′ phases, and fine, acicular α and κ phases precipitated inside β′ after subsequent aging. The largest proportion of the eutectoid microstructure, which underwent severe selective phase corrosion, was responsible for the lowest corrosion resistance of the annealed NAB. The quenched NAB possessed the most protective film and hence the highest corrosion resistance. The mechanical attack was primarily responsible for the CE damage for the as-cast, annealed and normarlized NABs. The quenched and quenched + aged NABs exhibited superior CE resistance because of the high hardness. The CE−corrosion synergy dominantly caused CE degradation, and it was largely attributed to corrosion-enhanced-CE.

Mechanical Properties and Cavitation Erosion Behavior of CeO2-Modified Dual-scale WC-10Co-4Cr Coating Prepared by HVOF

Mechanical Properties and Cavitation Erosion Behavior of CeO2-Modified Dual-scale WC-10Co-4Cr Coating Prepared by HVOF

Cavitation Erosion Characteristics for Different Metal Surface and Influencing Factors in Water Flowing System

The impact of cavitation erosion behavior on different metals in a water flowing system was investigated experimentally. A flowing system of water was built and a transparent observation window is designed to capture the cavitation flow. Erosion tests were carried out on red copper, brass, pure aluminum, and an aluminum alloy. The cavitation behaviors are presented by the weight loss and cavitation erosion rate, and related changes in the topography of the metal surface are also discussed. The variation in the cavitation erosion on metallic specimens with increasing time could be divided into three stages: rising stage, stable stage, and attenuation stage. The pure aluminum material had the lowest yield strength, and suffered the most severe cavitation erosion while brass had the highest yield strength and good mechanical properties, which suffered the least cavitation erosion. Furthermore, the roughness of the material surface was also one of the important factors affecting the cavitation erosion rate. The weight loss of milling specimens with higher surface roughness was slightly lower than that of grinding. The high roughness of the metallic surface increased the pressure loss along the flow path and the suppressed cavitation strength. This work provides an experimental reference for the anti-cavitation ability improvement in metal materials and promotes an understanding of the related mechanism.

Effect of corrosion on cavitation erosion behavior of HVOF sprayed cobalt-based coatings

Cobalt-based coatings have been widely applied to provide guidance to cavitation erosion (CE) and corrosion resistance since the coatings possessing superior mechanical and anti-corrosion properties. In this study, we prepared cobalt-based alloy (Stellite 21) coating and WC-17Co coating on 1Cr18Ni9Ti by HVOF. The CE resistances were evaluated in deionized water and 3.5 wt% NaCl solution (NaCl solution), and the anti-corrosion properties were studied using polarization tests. Results show that the WC-17Co coating had superior CE resistance than cobalt-based alloy coating in deionized water because of superior microhardness and fracture toughness characteristics. The WC-17Co coating presented much loose corrosion products (W/Co-oxides) in NaCl solution, which prone to be removed by the mechanical effect of the CE and accelerated the coating damage. On the contrary, the compact Cr oxides formed on cobalt-based alloy coating surface in NaCl solution could seal the pores, preventing to formation of erosion pits, and mitigate the damage of CE. Therefore, the cobalt-based alloy coating exhibited the best CE resistance in NaCl solution and had the potential to prevent CE in seawater.

Cavitation erosion behaviors and damage mechanism of Ti-Ni alloy impacted by water jet with different standoff distances

The cavitation erosion of Ti-Ni alloy is explored on a cavitating liquid jet with different standoff distances. The cavitation erosion characteristics of Ti-Ni alloy specimens are analyzed, and the influences that different standoff distances of the water jet have on cavitation erosion are explored. The results of cavitation erosion outcomes under different standoff distances of 6 mm, 8 mm, 10 mm, 12 mm, 14 mm and 16 mm show slight deformation, grain boundary cracking and formation of initial micro-pits, pits of maximum depth around 50 μm, more pits of maximum depth around 80 μm with micro-cracks, obvious plastic deformation traces with some pits, bulges and slip bands, respectively. When the Ti-Ni alloy is impacted by water jet with a standoff distance of 12 mm for 4 hrs, the surface microstructure undergoes substructural evolution and new fine grains form, with obvious stress concentration and dislocation accumulation appearing on the subsurface.

Cavitation Erosion Behavior of Nb Strengthened Duplex Stainless Steel Surfacing Layer

Cavitation Erosion Behavior of Nb Strengthened Duplex Stainless Steel Surfacing Layer

Corrosion and cavitation erosion behaviors of the manganese-aluminum-bronze cladding layer prepared by MIG in 3.5% NaCl solution

A cladding manganese-aluminum-bronze (MAB) layer was obtained by metal-inert gas welding (MIG) on a cast MAB plate, and its corrosion and cavitation erosion (CE) behaviors in 3.5% NaCl solution were evaluated. The cast MAB was composed of coarse α, β phases and large rosette κ precipitates. A much finer and more homogeneous microstructure was obtained in the cladding layer. The corrosion rate of the cladding layer was 19.35% lower than that of the cast MAB. Much thicker corrosion products and deeper corrosion pits were found on the cast substrate as a result of the dissolution of κ phases and preferential corrosion at β phases. In contrast, the cladding layer underwent uniform and slight corrosion because of the homogeneous microstructure. The CE rate of the cast MAB was 19.17% larger than that of the cladding layer. Mechanical impact was the dominated factor responsible for the CE damage for both the two materials. For the cast MAB, the β phases underwent cleavage fracture under the cavitation stress. Cracks initiated at α/κ phase boundaries and caused the detachment of κ phases. The propagation of long cracks inside the α phases resulted in groove-shaped cavities. The slightly higher CE resistance of the cladding layer was benefited from the microstructure refinement and modestly increased hardness. However, the cladding layer was also severely eroded with many narrow cavities on the surface due to the highest proportion of the soft α phase in the microstructure.

Investigations of Cavitation Erosion and Corrosion Behavior of Flame-Sprayed NiCrBSi/WC-12Co Composite Coatings.

Flame-sprayed NiCrBSi/WC-12Co composite coatings were deposited in different ratios on the surface of stainless steel. Oxyacetylene flame remelting treatment was applied to surfaces for refinement of the morphology of the layers and improvement of the coating/substrate adhesion. The performance of the coated specimens to cavitation erosion and electrochemical corrosion was evaluated by an ultrasonic vibratory method and, respectively, by polarization measurements. The microstructure was investigated by means of scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX). The obtained results demonstrated that the addition of 15 wt.% WC-12Co to the self-fluxing alloy improves the resistance to cavitation erosion (the terminal erosion rate (Vs) decreased with 15% related to that of the NiCrBSi coating) without influencing the good corrosion resistance in NaCl solution. However, a further increase in WC-Co content led to a deterioration of these coating properties (the Vs has doubled related to that of the NiCrBSi coating). Moreover, the corrosion behavior of the latter composite coating was negatively influenced, a fact confirmed by increased values for the corrosion current density (icorr). Based on the achieved experimental results, one may summarize that NiCrBSi/WC-Co composite coatings are able to increase the life cycle of expensive, high-performance components exposed to severe cavitation conditions.

Effects of Bacillus sp. adhesion on cavitation erosion behaviour of nickel aluminium bronze in artificial seawater

This study evaluated the cavitation erosion behaviour of a commonly used material in the marine environment, nickel aluminium bronze (NAB), after exposure to the adhesion of Bacillus sp. biofilm in artificial seawater. Results showed that the biofilm could inhibit the corrosion progress, keeping κ phases intact and subsequently allowing the NAB to retain its cavitation erosion resistance. Detailed discussion about the effect of the biofilm on cavitation erosion behaviour of NAB was presented. Furthermore, the importance of the κ phases for resisting cavitation erosion was evidenced by in-situ SEM, and a correlation of the decrease in hardness and the increase in mass loss during cavitation erosion was built.

Comparison of cavitation erosion behavior of 45 steel and 0Cr18Ni9Ti stainless steel

Abstract A cavitation erosion test of 0Cr18Ni9Ti stainless steel and 45 steel sample was performed in an ultrasonic vibration apparatus. The cavitation erosion behavior was studied by means of metallographic microscope, Vickers hardness test, scanning electron microscopy and mass loss analysis. The results showed that the surface hardness had an obvious influence on cavitation erosion, the higher the hardness, the better the cavitation erosion resistance was. Plastic deformation and fatigue fracture were the main mechanics of cavitation erosion of 0Cr18Ni9Ti stainless steel, whereas cavitation erosion of 45 steel was accompanied by oxidation, which will intensify cavitation erosion. Reasonable surface modification technology should be adopted for 0Cr18Ni9Ti stainless steel to improve surface hardness, and suitable surface protection technology must be used to resist cavitation erosion and oxidation for 45 steel under cavitation conditions.

Friction surfacing of precipitation hardening stainless steel coatings for cavitation erosion resistance

The cavitation erosion (CE) behavior of friction-surfaced (FSed) 17-4PH precipitation hardening stainless steel coatings without/with post-aging (H900) in 3.5 wt% sodium chloride solution at 25 °C was investigated. The FSed 17-4PH coatings were more CE resistant than the AISI 304 substrate by 1.35-fold owing to grain refinement, high dislocation density in martensite and increase in hardness. Despite crack initiation at the soft δ-ferrite, the surrounding refined grains of martensite (α’) retarded the growth of cracks during CE. Moreover, the initiation sites for CE including the sulfide inclusions and the incoherent copper precipitations in the AR 17-4PH, were fragmented and dissolved into the α’ matrix after FS. Thus, the synergistic corrosion effect was suppressed and beneficial to the CE resistance of the FSed coatings. The effect of FS processing parameters on the CE resistance of the FSed coatings was negligible. After H900, the CE resistance of the FSed coatings was further improved by 1.9-fold due to the effective hardness increment and the formation of reversed austenite.

Cavitation erosion behavior of high velocity oxy fuel (HVOF) sprayed (VC + CuNi-Cr) based novel coatings on SS316 steel

A well-known hard material (VC) has not been explored as potential candidate for surface modifications to overcome the problem of cavitation erosion (CE) in hydro machinery components. Therefore, in this course of work, VC has been blended with a malleable and soft binder material (CuNi-Cr) in three different proportions (VC, VC + 50%CuNi-Cr, and CuNi-Cr) and coated over SS316 steel with the help of HVOF spraying system. It has been observed that with the increase in VC content in the candidate coatings, the hardness, porosity, and thickness increased. CE tests were carried out with the help of an in-house fabricated cavitation erosion apparatus as per ASTM G134 Standard. The CE resistance of SS316 steel was found to be enhanced with the application of HVOF sprayed VC and CuNi-Cr based coatings. HVOF coating prepared with 100% VC content have showed excellent wear resistive properties owing to its maximum hardness (1023 HV 9.81N ) and better rebounding properties due to maximum thickness and porosity. CE parameters consisting of highest velocity of jet, intermediate stand-off distance (SOD) and normal impedance were found to be dominating to produce maximum cavitation erosion. Moreover, SS316 steel have showed ductile mode of failure with signatures of material removal as overlapped CE pits and plastic deformation sites. However, the mode of failure for coatings have been changed from ductile to brittle with the increase in VC content in the coating matrix with signatures changes from plastic deformation to cracks and pores in case of CuNi-Cr and VC coatings, respectively. • VC and CuNi-Cr composite coatings have been efficaciously prepared using HVOF spray process. • Microhardness of coatings was reported to be increased with increase in VC content. • Erosion resistance of SS316 steel was found to be significantly improved after deposition of coatings. • Mode of failure for coatings have been changed from ductile to brittle with the increase in VC content.