Cavitation Erosion Behavior Research Articles

Effect of 3.5 % NaCl solution with different Na2S concentrations on ultrasonic cavitation erosion behaviors of HVOF sprayed WC-Ni coatings

In this article, the WC-10Ni coatings were fabricated by HVOF spray, then the ultrasonic cavitation erosion performances of the coatings in distilled water and 3.5 wt% NaCl solution with various Na2S concentrations (0, 20 and 200 ppm) were investigated. The results of the cumulative volume loss of the coating in different mediums showed that the coating exhibited enhanced cavitation erosion resistance with the increase of Na2S concentrations in medium. The reason for the improvement on the cavitation erosion performance was the growth of corrosion product films containing sulphide. In comparison with the coating after cavitation erosion in medium without Na2S, no large craters and deep grooves were observed on the eroded coating surface in medium with Na2S. The ultrasonic cavitation damage of the coating manifests as the spall of the metal binder phase (Ni) and exposure of the hard phase (WC).

Effect of pre-corrosion on the cavitation erosion performance of two aluminum bronzes in 3.5% NaCl solution

The cavitation erosion (CE) behaviors of two aluminum bronzes after pre-corrosion in 3.5% NaCl solution were studied. Results indicated that the CE rate was increased by a factor of 82% for the nickel aluminum bronze (NAB) and 26.73% for the manganese aluminum bronze (MAB) after 30 days’ pre-immersion, compared with the results of the corresponding fresh sample without pre-corrosion. Mechanical impact was dominantly responsible for the CE damage of the pre-corroded samples. Pre-corrosion increased the E/T (the contribution of pure erosion to the CE-corrosion damage) value from 42.66% to 65.20% for the NAB and from 72.46% to 80.13% for the MAB. After pre-immersion, pits appeared at the eutectoid microstructure in the NAB and the network-shaped β phases in the MAB because of selective phase corrosion. This increased the surface roughness and weakened the surface mechanical property. Therefore, large and deep cavities and remarkable material loss were created due to the collapse of eutectoid microstructure in the NAB and the detachment of κ phases and brittle fracture of β phases in the MAB. The grievous CE damage of the MAB samples was highly attributed to the inferior mechanical property. In contrast, pre-corrosion had a much greater influence on the CE behavior of the NAB, because the CE resistance was remarkably deteriorated as a result of the corrosion damage at the eutectoid microstructure.

Selective phase corrosion and cavitation erosion behaviors of various copper alloys in 3.5% NaCl solutions with different pH values

The stability of each phase in nickel aluminum bronze (NAB), manganese aluminum bronze (MAB) and manganese brass (MB) was characterized by scanning Kelvin probe force microscopy (SKPFM). Selective phase corrosion (SPC) and cavitation erosion (CE) behaviors of these materials were studied in 3.5% NaCl solution with different pH values. The results show that the κ phase with the lowest stability is dissolved in the acidic solution (pH 2) for each material. In the neutral solution (pH 6.8), the Al-abundant κ phases in NAB are preserved, whereas the Fe-rich κ phases in MAB and MB are dissolved. In the alkaline solution (pH 12), pitting corrosion occurs at the κ phases in MAB and MB and at the κII phase in NAB. In each solution, NAB possesses the highest CE resistance, followed by MAB and MB. In the acidic solution, SPC remarkably intensifies the CE damage and CE−corrosion synergy contributes largely to the CE degradation. In other solutions, slight SPC occurs and each material exhibits a mechanical attack- dominated CE mechanism.

Effect of water temperature and induced acoustic pressure on cavitation erosion behaviour of aluminium alloys

Cavitation erosion is a major challenge for marine and fluid machinery systems. This study investigated the erosion performance of two as-cast aluminium alloys exposed to acoustic cavitation in water at temperatures of 10–50 °C and those were then compared with an extruded wrought alloy tested specifically at the temperature of maximum erosion. The results showed that the as-cast A380 alloy displayed exceptional resistance to cavitation erosion, with the lowest mass loss and surface roughness. This finding suggests that the as-cast A380 alloy is a suitable choice for lightweight, high-performance components in applications where cavitation resistance is critical.

Cavitation erosion and corrosion-cavitation synergism behaviour of CoCrFeNiMnTi x high entropy alloy coatings prepared by laser cladding

ABSTRACT Cavitation erosion and corrosion-cavitation synergism behavior of CoCrFeNiMnTi x (x = 0.5, 1.0, 1.5, 2.0 in atomic ratio) high entropy alloy coatings were analyzed. The sample with x = 1.0 showed the best cavitation erosion resistance due to the low weight loss and the maximum erosion rate. The protective ability of passivation film also displayed an increased first and then decreased tendency with the increase of Ti content as indicated by corrosion-cavitation synergism determined by open circuit potential method under cavitation erosion and quiescence condition. The sample with x = 1.0 displayed good re-passivation ability of passivation film according to open circuit potential behavior under cavitation erosion and quiescence condition. In general, the sample with x = 1.0 exhibited the highest cavitation erosion, the best self-repairing ability of the passivation film under the corrosion-cavitation synergism condition, which showed a great potential in the application of ocean engineering field as fluid-passing parts.

Research on the Influence of the Heat Treatment Temperature on the Cavitation Behavior of the Aluminum Alloy 2017 A

The good mechanical properties of aluminum alloy 2017 A have determined its use in a wide range of applications in which cavitational solocitations occur, such as hydraulic actuation installations, heat engine blocks, boat propellers and sloops, pumps in the cooling system of thermal engines, wings and ogives of airplanes. Currently, research is focused on the development of procedures for improving the resistance to cavitational erosion of these materials. This paper presents the results of the research on the cavitation erosion behavior of the material subjected to thermal aging treatment at different temperatures of 140 °C and 180 °C respectively and a constant holding time of 12 hours. The research was carried out according to the ASTM G32-2016 norms, on a vibrating device with piezoceramic crystals from the Cavitation Laboratory of the Polytechnic University of Timisoara. The research results, based on characteristic curves, mechanical properties, micro and macro structural images, showed that the sample kept for 12 h at a temperature of 180 °C is weaker than the control sample, during the sample time kept for 12 h at a temperature of 140 °C, has a small increase, even if, compared to the control sample (without heat treatment), the hardness is lower.

The Influence of Heat Aging Treatments on the Cavitation Erosion Behavior of a Type 6082 Aluminum Alloy.

It is known that a number of parts that operate in liquid media, such as the propellers of motorboats and pleasure river vessels, as well as the rotors of household pumps and the radiators and pumps in the cooling system of motor vehicles are made, as a rule, of aluminum-based alloy. Research during maintenance leads to the conclusion that, in certain operating conditions, due to the turbulent character of the flow, with pressure drops to below the vaporization level, it inevitably reaches the threshold of cavitation, which manifests itself through its effects, especially through erosion. To increase the lifetime, these alloys are currently subjected to techniques to improve the structure's resistance to the cyclic stresses of cavitational microjets. Among these techniques are volumetric heat treatments, which lead to changes in the microstructure and mechanical property values, with an effect on the behavior and resistance to cavitation erosion. This paper studies the influence of heat aging treatments on the cavitation erosion behavior of an aluminum alloy type 6082, in the cast state. The heat treatments applied were 140 °C/1 h, 12 h, 24 h and 180 °C/1 h, 12 h, 24 h. The MDEmax and MDERs parameters were determined and a correlation could be made between the values of the mechanical-resilient characteristics and the resistance to cavitation erosion in the case of aluminum alloy 6082.

Corrosion and cavitation erosion behaviors of laser clad FeNiCoCr high-entropy alloy coatings with different types of TiC reinforcement

By using laser cladding (LC), high entropy alloy coatings (HEACs) with FeNiCoCr as the base material and TiC added directly (D-TiC) and in-situ (I-TiC) were created. The phase composition, microstructure, mechanical characteristics, electrochemical corrosion, and cavitation erosion behavior of HEACs were examined in relation to two TiC addition methods, and a thorough investigation of the effects of mechanical characteristics and corrosion resistance on cavitation erosion behavior was conducted. Large clusters of TiC were visible in the D-TiC HEAC, in contrast to the sparse and scattered distribution of them in the I-TiC HEAC. The average grain size of the composite coating substantially fell from 25.7 μm for FeNiCoCr coating to 11.8 μm for D-TiC coating and 9.4 μm for I-TiC coating when TiC were included in the skeleton. The I-TiC composite coating precipitated by nucleation and growth with the maximum average microhardness of 440 ± 6 HV under the combined action of solid solution strengthening, fine crystal strengthening, and second phase strengthening. In 3.5 wt% NaCl solution, the galvanic corrosion between TiC particles and the FCC matrix significantly weakened the corrosion resistance of the D-TiC HEAC, with the Icorr reaching 3.47 × 10−2 ± 0.8 μA/cm2. The I-TiC HEAC exhibited approximately equal corrosion resistance to FeNiCoCr with an Icorr of merely 5.92 × 10−3 ± 0.3 μA/cm2. Varying cavitation incubation periods (IPs) existed in 316 SS and HEACs at the beginning of the cavitation experiment. The mean depth of erosion rate (MDER) of FeNiCoCr, D-TiC and I-TiC coatings was 0.19 ± 0.09, 0.42 ± 0.04, and 0.15 ± 0.02 μm h−1, respectively, which was only 1/5, 1/2, and 1/6 of that of substrate (0.90 ± 0.13 μm h−1). The cavitation surface of 316 SS was full of craters and cracks without any original surface. Meanwhile, due to the weak interfacial bonding strength between TiC/HEA, the cavitation erosion morphologies of D-TiC HEAC contained spallation of large TiC particles. Attributed to its ideal mechanical and corrosion resistance, the I-TiC composite coating demonstrated the best resistance to cavitation erosion.

Effect of binder phases on the cavitation erosion behavior of HVOF sprayed WC-based coatings

In order to address the issue of cavitation erosion (CE) damage in marine mechanical components, WC-10Co4Cr (WCC), WC-10Co (WC1) and WC-17Co (WC2) coatings were prepared on the surface of 316L stainless steel using high-velocity oxygen-fuel (HVOF) spraying technique. The study investigated the microstructures, phases, mechanical properties and CE behavior of the coatings with different binder phases. The effects of the type and content of binder phase on the CE resistance and mechanism of the coatings were studied by compared the differences of volume loss rate (VLR) and eroded surface morphologies between the coatings. It was observed that all three coatings were dense and tightly bonded to the substrate. The primary phases identified in the coatings were WC, W2C and Co3W3C. Compared with the WC1 and WC2 coatings, the WCC coating demonstrated superior CE resistance with the lowest volume loss rate (VLR). The VLR of the WC1 and WC2 coatings was approximately four times higher than that of the WCC coating. The binder phase of Co-Cr improved the mechanical properties and the bonding strength of hard and binder phase, which reduces the brittle detachment of WC particles. In addition, the WCC coating had high microhardness and elastic modulus (E), H/E and H3/E2, which hindered the initiation and propagation of fatigue cracks. The initiation of CE damage occurred at the original defects, such as pores, cracks. The primary CE mechanism of the coatings was the interlinking of cavitation craters, lamellar spalling caused by the fatigue cracks propagation along the interlayer. The brittle detachment of WC hard particles also occurred significantly in WC1 and WC2 coatings due to loss of the binder phase. It was concluded that the binder phase markedly influenced the CE resistance and mechanism of the coatings, the addition of Cr showed the most pronounced effect.

Effect of Heat Treatment on the Cavitation Erosion Behavior of Nanocrystalline Surface Layer of 304 Stainless Steel

In this study, a nanocrystalline layer composed primarily of martensite phase was prepared on the surface of 304 stainless steel. Furthermore, the martensite phase content in the nanocrystalline layer was adjusted by heat treatment at 500 °C and 550 °C, respectively, and the cavitation erosion resistance of the nanocrystalline layer before and after heat treatment was investigated. The results showed that the nanocrystalline layer before and after heat treatment exhibited excellent erosion resistance, with cumulative mass loss of approximately 1/7, 1/5, and 1/3 that of the traditional 304 stainless steel, respectively. The nanocrystalline layer could significantly inhibit the growth of cavitation pits due to the high density of grain boundaries. However, due to the decrease in hardness of the nanocrystalline layer after heat treatment, the propagation speed of cavitation cracks was accelerated, and the cavitation erosion performance of the nanocrystalline layer showed a downward trend.

Effect of variation of WC reinforcement on metallurgical and cavitation erosion behavior of microwave processed NiCrSiC-WC composites clads

Components operating in fluid handling systems most frequently experience cavitation erosion. The coatings/claddings fabricated by microwave irradiation method can remarkably improve cavitation erosion. In the present work, WC reinforced NiCrSiC based metal matrix composite clads with varying weight percentage of WC particles were developed on SS 316 steel using microwave heating method. The metallurgical and microstructural study of composite clads were analyzed using SEM/EDS, XRD and porosity, microhardness was also investigated. Cavitation erosion behavior of the claddings were evaluated using vibratory cavitation erosion tester. The failure mechanism due to cavitation erosion was explored using SEM study. The relationship of cavitation erosion behavior with variation in weight percentage (10%, 20%, and 30%) of reinforced particles in the composite clad was also explored. It has been observed that with an increase in the weight percentage of WC particles, the cavitation erosion rates decreased drastically initially (37.9%) and, but later significant change was not observed (4.89%, 2.44%). Eroded surface study revealed that with increase in the weight percentage of WC reinforcement the mode of damage changes from ductile to brittle. Further it was studied that the pits, crater, micro-cracks, and plastic deformation were the primary wear mechanisms.

Ultrasonic Cavitation Erosion Behavior of CoCrxFeMnNi High-Entropy Alloy Coatings Prepared by Plasma Cladding

CoCrxFeMnNi (x represents the atomic percentage of Cr element, x = 20, 25, 30, and 35, denoted as Cr20, Cr25, Cr30, and Cr35 alloys) high-entropy alloy (HEA) coatings were cladded by plasma arc on the surface of 0Cr13Ni5Mo steel. The effects of Cr elements on the cavitation erosion mechanisms were studied by comparing the differences of microstructure, microhardness, cavitation erosion volume loss (CVL), cavitation erosion volume loss rate (CER), and eroded surface morphologies between the coatings. As the Cr content increased, the microhardness of the coatings increased continuously, and the microstructure transformed into fine dendrites. The microhardnesses of Cr20, Cr25, Cr30, and Cr35 were 223.9 HV, 250.5 HV, 265.2 HV, and 333.7 HV, respectively. With structural change, the slip pattern shifted from uniform distribution to distribution along the grain boundary, increasing slip resistance. Additionally, strain hardening capacity increased with reduced stacking fault energy (SFE). The resistance to cavitation erosion (CR) of the HEA increased with the increase in Cr content. The CVL of 20 h cavitation erosion of Cr35 coating was only 26.84% of that of 0Cr13Ni5Mo steel, and the peak CER was only 28.75% of that of 0Cr13Ni5Mo steel. The fracture damage mechanisms of the four HEA coatings were an obvious lamellar structure and fibrous fracture.

Strengthening Effect of Nb on Microstructure and Cavitation Erosion Behavior of Duplex Stainless Steel Surfacing Layer

Strengthening Effect of Nb on Microstructure and Cavitation Erosion Behavior of Duplex Stainless Steel Surfacing Layer

Effect of Initial Surface Scratches on the Cavitation Erosion Behavior of 316L Stainless Steel Substrates and 316L Stainless Steel Coatings

Rough surfaces have been widely considered as negative factors affecting cavitation erosion resistance. However, this study presented the opposite result. Here, 316L stainless steel substrates and the arc-sprayed 316L stainless steel coatings were subjected to a specific grinding process that introduced scratches on the surfaces. The surface hardness values of these ground specimens were measured to evaluate the influence of the grinding-induced strain hardening. The cavitation erosion performance of the specimens was evaluated. The results showed that rough surfaces with scratches could enhance the cavitation erosion resistance, particularly at the early stage of cavitation erosion. The scratches had a greater effect on the cavitation erosion resistance of the coatings than on the substrates. Moreover, rough surfaces with initial surface scratches could extend the incubation period of the 316L stainless steel substrates due to the inhibition of the plastic deformation. The SEM observation showed that the scratch structure of the coating surface inhibited the growth of cracks and the propagation of cavitation pits. This study could also serve as a reference for investigating the cavitation erosion behaviors of materials with a particular surface feature.

Cavitation erosion behavior and anti-cavitation erosion mechanism of NiTi alloys impacted by water jet

The cavitation erosion behavior and anti-cavitation erosion mechanism of NiTi alloys was explored by water jet equipment conforming to ASTMG134 international standard. The cumulative mass loss rate of NiTi alloys changed slowly by water jet impact within 180 min, then increased sharply and decreased obviously after 240 min. When the impact time lengths were prolonged from 30 min to 60 min, the macroscopic deformation did not significantly increase on the surface of the sample. It was mainly due to the superelasticity of NiTi alloys, resulting in a prolonged cavitation incubation period of NiTi alloys impacted by water jet. When the impact time length was 180 min, work hardening occurred along with the plastic deformation, and cavitation pits appeared on the surface of the sample. When the impact time lengths were extended from 240 min to 300 min, there was no obvious increase in cavitation pits and the material spalling. This is mainly due to the formation of new grains by the recombination of dislocations on the surface and the piling up of dislocations on the grain boundaries at a distance from the impact surface of NiTi alloys. The formation of new grains has consumed high-density dislocation and distortion energy, which can reduce the cavitation erosion damage on NiTi alloys caused by water jet impact. With the increase of water jet impact time, the surface of NiTi alloys undergoes a process of plastic deformation→ work hardening→ increase in dislocation density→ grain refinement→ proliferation of refined grains. Additionally, the residual stress of NiTi alloys with different impact time lengths remained high and they could inhibit the initiation and propagation of cavitation cracks.

Effect of variation of ceramic reinforcement content on metallurgical and cavitation erosion behaviour of microwave processed composite clads

The effect of varying (0%-30% by weight) reinforcement (Cr3C2) on the different characteristics of microwave processed composite clads (Ni-based (EWAC) matrix) was determined. The microstructure of composite clads showed growth of randomly orientated lamellar bands (Cr-Fe-C) rich phase in the Ni-Fe-Cr rich matrix, which confirmed the metallurgical bonding of clads with substrate. Higher microhardness values, with a lower standard deviation, were observed in the 30% Cr3C2 reinforced clad. Excellent cavitation erosion resistance of EWAC + 30% Cr3C2 composite clads, among all other clads and substrate samples, was observed. Synergy of higher microhardness and toughness resulted in significant improvement in the cavitation erosion resistance. Formation of pits, craters and plastic deformations were mainly responsible for the cavitation erosion failure of clads and substrate samples. The transition of damage from ductile mode to dual (brittle and ductile), and further brittle mode was observed with increase in weight percentage of reinforcement.

Effect of Variation of Ceramic Reinforcement Content on Metallurgical and Cavitation Erosion Behaviour of Microwave Processed Composite Clads

Effect of Variation of Ceramic Reinforcement Content on Metallurgical and Cavitation Erosion Behaviour of Microwave Processed Composite Clads

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.