Effect Of Ultrasonic Impact Treatment Research Articles

Effect of ultrasonic impact treatment on surface residual stress, microstructure and electrochemical properties of the hot-rolled S355 steel

The effects of ultrasonic impact treatment (UIT) on the microstructure, corrosion resistance, and surface residual stress of hot-rolled S355 steel were investigated. In addition, the improving mechanism of the UIT induced corrosion resistance was discussed. The results show that the UIT can effectively improve the corrosion resistance of hot-rolled S355 steel, and corrosion current density reduction is demonstrated. Based on the corrosion morphology, it can be found that after the UIT the corrosion pits became shallower, the oxide layer becomes denser, and more flocculent structures appear on the surface as well as the appearance of dense irregular curved structures. Moreover, the residual tensile stress on the surface of the hot-rolled S355 steel is transformed into residual compressive stress after the UIT. The grains are refined, and the microhardness is increased, which implied that the significant plastic deformation has occurred on the surface of the hot-rolled S355 steel. The findings confirm that dense oxides could be generated on the surface of hot-rolled S355 steel treated by ultrasonic impact since the residual compressive stress is introduced, the plastic deformation is induced, and the grains are refined.

Promoting densification and strengthening effect of ultrasonic impact treatment on Haynes 230 alloy manufactured by laser powder bed fusion

Laser powder bed fusion (LPBF) has been extensively investigated owing to its high geometry formation accuracy and excellent mechanical properties. However, the LPBFed Haynes 230 parts typically display poor tensile and wear properties due to internal porosity. In this work, the ultrasonic impact treatment (UIT) was applied as a post-treatment to the LPBFed Haynes 230 alloy, porosity and microstructure modulation were performed to improve the strength properties and wear resistance. The pore closure and microstructure were studied by numerical simulations and experiments, and the mechanisms of increasing densification and strength were discussed. Results show that UIT can effectively close pores and reduce porosity, the internal porosity of the ultrasonic impacted layer for one, two, and three times decreases by 63.6 %, 70.9 %, and 81.8 %, respectively. Pore closure is attributed to the residual compressive stress and shear stress introduced by UIT. Besides, the UIT weakened texture strength and refined grains, especially promoting the formation of fine grains. Meanwhile, it also promotes the formation of a high dislocation density and improves the phase structure distribution. Furthermore, the ultimate tensile and yield strengths of the optimal impact process increased by 9.6 % and 34.6 %, respectively. The improvement in strength was attributed to dislocation, grain boundary, and promoting densification strengthening. The average friction coefficient reduces by 4.9 %–14.6 % by refining the surface grains and increasing dislocation density. This work has verified the feasibility of improving the mechanical properties and pore closure of the LPBFed Haynes 230 alloy by UIT.

Effect of ultrasonic surface impact on the microstructural characterization and mechanical properties of 316L austenitic stainless steel.

In the present study, effect of ultrasonic impact treatment (UIT) on the microstructural characterization and mechanical properties of 316L stainless steel (hereinafter referred to as 316L) was investigated experimentally. The fatigue fracture mechanism of 316L before and after UIT was revealed. The experimental results indicated that the martensitic grain size induced at the impact edge was about 2.00 Å. The surface modified 316L formed a gradient nanostructure and induced a martensitic phase transformation. The hardness of the surface layer of the modified 316L was twice the hardness of its matrix. The tensile strengths of 316L before and after UIT were 576 MPa and 703 MPa, respectively. The stretching stripes of 316L were more disordered after UIT. The fatigue strengths of 316L before and after UIT were 267 MPa and 327 MPa, respectively. The fatigue cracking of 316L started from the austenite grain boundaries. The fatigue fracture surface was relatively rough. The fatigue crack sources of the modified 316L came from internal inclusions. The inclusions were oxides dominated by SiO2. As the stress range increased, the crack initiation site migrated to the interior and the fatigue fracture surface became flatter.

Effect of ultrasonic impact treatment on the microstructure and properties of laser cladded CoCrFeNiMox high entropy alloy coatings

Ultrasonic impact technology was applied to improve the property of laser cladded CoCrFeNiMox (x = 0, 0.25, 0.5, 0.75) high entropy alloy coatings on the surface of low-carbon steel. The phase structures and the microstructural characteristics were studied in detail through X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The microhardness distributions, wear resistance, and corrosion resistance of the samples are illustrated using a microhardness tester, a micro-friction and wear tester, and an electrochemical test system. Single FCC phase solid solution was identified to be the main phase structure, with the interdendritic σ phase precipitating with the increasing Mo content. Although ultrasonic impact treatment did not change the phase composition of the high-entropy alloy (HEA) cladding coatings, evident plastic deformation and broken σ phase appeared near the surface of the impacted layers. Through the combined effects of dislocation, fine-grain, and dispersion strengthening, the microhardness of the CoCrFeNiMox coatings was improved after ultrasonic impact treatment. In addition, ultrasonic impact treatment decreased the surface roughness and increased the wear resistance, and the main wear mechanism of the impacted layers changed from fatigue spalling to abrasive wear. The wear mass of the ultrasonically impacted layers was approximately 92 % of the laser cladded CoCrFeNiMox coatings. Furthermore, ultrasonic impact treatment improved the corrosion resistance of the HEA coatings.

Effect of Ultrasonic Impact Treatment on Microstructure and Fatigue Life of 3D Printed Ti–6Al–4V Titanium Alloy

Effect of Ultrasonic Impact Treatment on Microstructure and Fatigue Life of 3D Printed Ti–6Al–4V Titanium Alloy

Fatigue Performance Analysis of Welded T-Joints in Orthotropic Steel Bridge Decks with Ultrasonic Impact Treatment.

This study aims to assess the effect of ultrasonic impact treatment (UIT) on the exterior weld seam of S355J2 T-joints used in orthotropic steel bridge decks. The microstructure and mechanical behavior of T-joints after UIT was investigated in this study. Fatigue tests of T-joints before and after UIT were performed. The stress concentration at the interior and exterior weld toe of T-joints was considered using the traction structural stress method. The results showed that hardness increases by 10% due to the localized grain refinement caused by UIT. UIT significantly improves the fatigue life of T-joint specimens by 350% and 150% at stress ratios of 0.1 and 0.3, respectively. As the transition angle between the weld profile and the base metal profile increases, the stress concentration factor decreases.

Effect of Ultrasonic Impact Treatment with Different Impact Energy and Head Shape on Surface Properties of U75V Heavy Rail

Effect of Ultrasonic Impact Treatment with Different Impact Energy and Head Shape on Surface Properties of U75V Heavy Rail

Effect of ultrasonic impact treatment on welding residual stress and fatigue resistance of doubly-welded rib-to-deck joints in OSD

Innovative doubly-welded rib-to-deck joints (DRJ) have been developed to enhance the fatigue life of orthotropic steel decks (OSD) used in steel bridges. However, the welding process and welding residual stress (WRS) distribution of DRJ are more complicated than those of conventional single-side welded rib-to-deck joints. To release WRS and improve the fatigue resistance of DRJ, ultrasonic impact treatment (UIT) and fatigue tests were performed in this study. The effect of the UIT process on the WRS distribution and fatigue resistance of the DRJ was investigated. Furthermore, the welding processes of the DRJ and UIT were simulated using the finite element method and validated against the relevant measurements. Subsequently, they were used to investigate the effect of the UIT process on the WRS distribution and represent the mechanism of fatigue failure of the DRJ. Compared with the as-welded specimens without UIT, the fatigue strength of the DRJ increased by more than 60%, and the UIT process altered the dominant fatigue failure mode of the DRJ. The fatigue crack, caused by a UIT-induced fold defect, tends to initiate at the bottom of the impact pit. Owing to the UIT process, the adverse tensile WRS in the weld toe is eliminated, and beneficial compressive residual stress is introduced, leading to an improvement in the fatigue strength of the DRJ.

Structure and Microhardness of Constructional Steel after Ultrasonic Impact Treatment at Negative Air Temperatures

The paper investigates the effect of ultrasonic impact treatment on the structure and microhardness of constructional steel 10G2FBYu (GOST). Ultrasonic impact treatment of these steel was carried out an air temperature of -30 °C.

Effect of ultrasonic impact treatment on the properties of CoCrFeNiCu high-entropy alloy coatings on steel by induction cladding

The aim of this study is to improve the comprehensive properties of CoCrFeNiCu high entropy alloy coating (HEAc) prepared by induction cladding by means of ultrasonic impact treatment (UIT). After UIT, the interdendritic segregation of Cu atoms on the surface of HEAc was inhibited, which made the dual-phase structure consisting of FCC1 Cu-rich phase and FCC2 Cu-depleted phase transform to a single-phase FCC. High density of the dislocation and the sub-grain boundary produced by UIT have hardened the surface of the HEAc, which strengthened microhardness, elastic modulus and wear resistance. The combination of the soft region and the hard region in the HEAc/substrate specimen with UIT made the strength increase but the elongation decrease. The inhibition effect of UIT on the Cu-rich phase alleviated the inhomogeneity of the passivation film, while the grain refinement and high-density dislocation promoted the growth of the passivation film, hindered the invasion of corrosive ions, and effectively improved the corrosion resistance of the HEAc surface.

Study on the influence of ultrasonic impact treatment (UIT) on stress evaluation of laser cladding coating by using metal magnetic memory technology

The effect of ultrasonic impact treatment (UIT) on stress of laser cladding coating evaluated with metal magnetic memory technology (MMMT) was discussed, so a stress control method was proposed. In this paper, a metal magnetic memory testing device of EMS-2003, a two-channel pen metal magnetic memory probe and a non-ferromagnetic three-dimensional electronically controlled displacement plat form were employed to collect Hp(y) signal defined as the normal component of MMM signal, and tensile test was carried out on LC-50 testing machine. To prove the theoretical analysis, the microstructure and three dimensional surface topography of coating under different repetition rates of UIT were observed by using optical microscope and laser scanning confocal microscopy. The results show that the influence of detection line on Hp(y) signal can be ignored, and the distribution of Hp(y) signals under different tensile loads are all approximately an oblique line, which can be explained by the magnetic dipole model. As tensile load increases, the magnetic field intensity gradient of Hp(y) signal (K) becomes higher, and after coating is in the plastic deformation state, the value of K becomes lower gradually as tensile load increases further. When tensile loads are the same, the value of K becomes higher gradually as the repetition rate of UIT increases. But as repetition rate of UIT increases, the slope of K becomes lower gradually, and the changes on microstructure and deformation caused by UIT are seen as main reasons. At last, the experimental results were theoretically discussed based on the magnetostriction effect, and it was thought that the change on orientation of magnetic domain was the main reason.

Influence of ultrasonic impact treatment and working current on microstructure and mechanical properties of 2219 aluminium alloy wire arc additive manufacturing parts

Ultrasonic impact treatment (UIT) is considered to solve the defects of wire arc additive manufacturing (WAAM) components such as coarse grain size, large residual stress, and poor mechanical properties. In this paper, the effects of UIT on the microstructure and mechanical properties of 2219 aluminum alloy WAAM components were systematically studied. The effect of UIT on grain size and porosity was investigated by metallographic experiments. Electron backscattering diffraction (EBSD) was used to analyze the effect of UIT on grain orientation and texture. The chemical composition and phase composition were characterized by energy dispersive spectrum (EDS) and transmission electron microscopy (TEM). The effect of UIT on mechanical properties was analyzed by tensile test. Therefore, the influence and strengthening mechanism of UIT on WAAM components are analyzed.The results show that UIT can refine the grain size and reduce porosity. In addition, UIT can increase the dislocation density, improve the surface residual stress, and distribute the precipitated phase evenly in the matrix, thus effectively improving the mechanical properties of the WAAM components. This study provides a basis for improving the quality of WAAM components, and has reference value for the application of WAAM and UIT technology, as well as the regulation of the microstructure and properties of 2219 aluminum alloy.

Effect of ultrasonic impact treatment on microstructure and corrosion behavior of friction stir welding joints of 2219 aluminum alloy

Ultrasonic Impact Treatment (UIT) was performed to improve the corrosion resistance of 2219 aluminum alloy friction stir welding (FSW) joints. Results showed that the coarse grains on near surface of FSW joints were obviously modified and refined after UIT, and the thickness of the modified layer of different sub-regions was ranged from 90 to 120 μm. UIT increased intergranular corrosion resistance of 2219 aluminum alloy FSW joints in salt spray corrosion atmosphere. Free-corrosion potential of heat-affected zone (HAZ), which presented the worst corrosion resistance, was increased from −0.653 to −0.628 V, and the corrosion current density was decreased from 7.48 to 6.18 mA cm−2. The sensitivity index of stress corrosion cracking (SCC) of the joints was decreased from 0.139 to 0.129 in 3.5% NaCl solution after UIT, and the risk of crack initiation during SCC process was significantly inhibited. UIT improved the SCC resistance of 2219 aluminum alloy FSW joints by surface plasticity improvement, grain refinement and precipitates dissolution and redistribution.

Effect of ultrasonic impact treatment on corrosion fatigue performance of friction stir welded 2024-T4 aluminum alloy

ABSTRACT Friction stir weld joints of 2024-T4 are strengthened by ultrasonic impact treatment (UIT). After ultrasonic impact treatment, the grains on the surface of the sample are refined to form a dense deformation layer, and residual compressive stress is applied on the surface of the sample. The corrosion rate and mass-loss rate of the UIT sample are significantly lower than those of the non-UIT sample, and uniform corrosion is exhibited. The average life of the UIT samples in the air is 1.74 times that of the non-UIT samples; meanwhile, the average life of the UIT samples in 3.5% NaCl solution is twice that of the non-UIT samples. The crack sources of the UIT sample in the air shift from the surface to the subsurface below the strengthening layer, whereas those of the sample in the 3.5% NaCl solution are located in the corroded area on the surface of the sample.

Effect of Ultrasonic Impact Treatment on the Microstructure and Properties of Laser Solid Formed Ti60 Alloy

Effect of Ultrasonic Impact Treatment on the Microstructure and Properties of Laser Solid Formed Ti60 Alloy

Effect of Ultrasonic Impact Treatment on the Microstructure and Properties of Laser Solid Formed Ti60 Alloy

Effect of Ultrasonic Impact Treatment on the Microstructure and Properties of Laser Solid Formed Ti60 Alloy

The effect of ultrasonic impact treatment on deformation and fracture of electron beam additive manufactured Ti-6Al-4V under uniaxial tension

The results of experimental investigations and molecular dynamics simulation of deformation and fracture of as-built wire-feed EBAM Ti-6Al-4V samples and the samples subjected to ultrasonic impact treatment are presented. Dislocation deformation of the samples under uniaxial tension is shown to occur through propagation of fine and coarse slip bands and shear bands. The ultrasonic impact treatment results in the formation of a 10 μm thick top layer consisting of the nanocrystalline α-Ti, β-Ti and TiO2 phases and an underlying 30–50 μm thick layer, which microstructure is characterized by curved and fragmented α-phase lamellae. As a consequence, dislocation sliding in the ultrasonically treated surface layer of the wire-feed EBAM Ti-6Al-4V samples is hindered. Molecular dynamics simulation has revealed that the grain boundary sliding and twinning are the main deformation mechanisms of the fragmented α-phase lamellae. The migration of the twin boundaries was happened by means of the development of reversible HCP→BCC→HCP transformations. At the prefracture stage the non-crystallographic shear bands nucleating in the underlying layers propagate in the ultrasonically treated surface layer. Intensive deformation inside the shear bands manifests itself in the formation of regions with ductile microrelief on the brittle fracture surface.

Numerical simulation of the effect of ultrasonic impact treatment on welding residual stress

Ultrasonic impact treatment (UIT) is an effective method that has been widely applied in welding structure to improve the fatigue properties of materials. It combines mechanical impact and ultrasonic vibration to produce plastic deformation on the weld joints surface, which introduces beneficial compressive residual stress distribution. To evaluate the effect of UIT technology on alleviating the residual stress of welded joints, a novel numerical analysis method based on the inherent strain theory is proposed to simulate the stress superposition of welding and subsequent UIT process of 304 stainless steel. Meanwhile, the experiment according to the process was carried out to verify the simulation of residual stress values before and after UIT. By the results, optimization of UIT application could effectively reduce the residual stress concentration after welding process. Residual tensile stress of welded joints after UIT is transformed into residual compressive stress. UIT formed a residual compressive stress layer with a thickness of about 0.13 mm on the plate. The numerical simulation results are consistent with the experimental results. The work in this paper could provide theoretical basis and technical support for the reasonable evaluation of the ultrasonic impact on residual stress elimination and mechanical properties improvement of welded joints.

Effect of ultrasonic impact treatment on surface stress evaluation of laser cladding coating by using critically refracted longitudinal wave

Based on the Lcr wave acoustoelastic effect, surface stress of laser cladding Fe314 alloy coating after ultrasonic impact treat (UIT) was measured, and relation between Lcr wave acoustoelastic coefficient and repetition rate of UIT was discussed in this paper. The laser cladding Fe314 alloy coating was prepared on surface of carbon steel and impacted with different repetition rates of UIT by using UIT-300 system. After that, the experimental system of stress measurement with Lcr wave, consisting of a ultrasonic wave generator, a digital oscilloscope and two Lcr wave transducers (including one transmitting transducer and one receiving transducer) with 2.5MHz frequency, was used to collect Lcr waves of coating with calibration test, and then the difference in time of flight between Lcr waves was calculated with the cross correlation theory. To explain experimental results, the microstructure and three dimensional surface topography of coating were observed by using SEM and LSCM. Results show that as repetition rate of UIT increases, the Lcr wave acoustoelastic coefficient increases, when it reaches 300%, the Lcr wave acoustoelastic coefficient also reaches the maximum, after that the Lcr wave acoustoelastic coefficient decreases irregularly as repetition rates of UIT increases further. Compared with the Lcr wave acoustoelastic theory, when stress is in the range of turning point stress, there is a deviation on experimental result, and that deviation becomes more obvious as stress and repetition rate of UIT increase. It is analyzed that the change of microstructure, deformation state and initial stress of coating caused by UIT and different repetition rate are main reasons.

Cumulative Fatigue damage of AA7075-T6 under Shot Peening and Ultrasonic Surface Treatments

One of the important aspects of mechanical design is improving fatigue life.; In this work, the effect of Ultrasonic impact treatment (UIP) and shot peening (SP)on constant cumulative fatigue life and fatigue strength of AA7075-T6 were studied; The sample group was machined and primed, and some specimens were treated using ultrasonic impact therapy (UIT) with one line of peening. Fatigue experiments were conducted under constant and variable amplitude (R=-1) at ambient temperature to determine the fatigue life of the S-N curve and fatigue strength during treatment 3.46% and 8.57% at 107 cycles for (UIT) and (SP). Cumulative fatigue damage testing was carried out for two steps loading it is observed that the fatigue life for SP and UIP treated specimens was improved compared to the unpeeled results. The fatigue endurance limit was enhanced by 35% for UIT and 54% for SP. The fatigue life for both treatments was much improved compared to as-received metal. These results also show a strong tendency of increasing fatigue strength after application of (UIT) and (SP) with an increase in mechanical properties of the material used.