Effect Of Ultrasonic Impact Research Articles

Study on the effect of ultrasonic impact on residual stress and deformation in welding arc additive manufacturing

Study on the effect of ultrasonic impact on residual stress and deformation in welding arc additive manufacturing

Effect of Ultrasonic Impact on the Microhardness and Microstructure of Friction Stir Welded Aluminum Alloy 2024

Effect of Ultrasonic Impact on the Microhardness and Microstructure of Friction Stir Welded Aluminum Alloy 2024

Microstructure, mechanical and corrosion properties of FeCrNiCoMnSi0.1 high-entropy alloy coating via TIG arc melting technology and high-frequency ultrasonic impact with welding

With the increase in studies on high-entropy alloys and their impressive structural properties, the preparation processes and applications of high-entropy alloys have become a popular research topic in metallic materials. In this paper, the preparation of FeCrNiCoMnSi0.1 high-entropy alloy coatings was carried out by the follow-welding high-frequency power ultrasonic impact composite TIG arc melting process, the effects of different power ultrasonic impacts on the microstructure and properties of the coatings are investigated. The results showed that the average grain size is reduced by 74 % (from 278 μm to 72 μm), the average microhardness is increased by 41 % from 568 HV1 to 807 HV1, the abrasion resistance is improved by 68 % under the effect of ultrasonic impact. The ultrasonic impact treatment process can effectively refine the microstructure of the coatings and improve the strength of grain boundaries. The corrosion resistance of the coating in 3.5 wt% NaCl solution is enhanced by 65 %, the corrosion type was changed from intergranular corrosion to uniform corrosion. This is mainly caused by the ultrasonic impact treatment which suppresses the elemental segregation of Cr and Mn and improves the grain boundary strength.

Effect of Ultrasonic Impact on the Fatigue Properties of TC4 Titanium-Alloy Laser-Welded Joints

Effect of Ultrasonic Impact on the Fatigue Properties of TC4 Titanium-Alloy Laser-Welded Joints

Effect of Ultrasonic Impact on the Organization and Friction Wear Performance of AZ31B Magnesium Alloy Micro-Arc Oxidation Composite Coating

To enhance the frictional wear performance of AZ31B magnesium alloy, a nanocrystalline layer was prepared by ultrasonic impact (UI) treatment on magnesium alloy samples, and the effects of different ultrasonic impact times (5 min, 10 min, and 15 min) on the organization and wear resistance of the composite coating were studied. The findings revealed that the maximum thickness of the composite coating was about 50 μm after 10 min of impact time, which was approximately 15 μm higher than that of the MAO coating. The elemental composition of the composite coating was mainly Mg, O, and Si elements, and the phase structure of the coating, mainly MgO and Mg2SiO4, was the same before and after UI. The microhardness value gradually decreased in a gradient with the increasing distance from the sample surface. The coating had a lower average coefficient of friction (0.18) and lower wear loss (1.56 mg) for the 15 min impact time. Moreover, a small amount of abrasive and adhesive wear served as the primary modes of wear.

Effect of Ultrasonic Impact on the Macrostructure and Strength of Dissimilar Aluminum and Titanium Alloys Joints Produced by Friction Stir Welding

Effect of Ultrasonic Impact on the Macrostructure and Strength of Dissimilar Aluminum and Titanium Alloys Joints Produced by Friction Stir Welding

Effect of Ultrasonic Impact on Corrosion Fatigue Properties of Titanium Alloy Welded Joints

Effect of Ultrasonic Impact on Corrosion Fatigue Properties of Titanium Alloy Welded Joints

Effect of Ultrasonic Impact on the Microstructure of Welded Joint of 2195 Al–Li Alloy

It is known that an ultrasonic impact during tungsten inert gas welding can refine the grains and improve the mechanical properties of the welded joints of aluminum alloys. However, the influence mechanism of the ultrasonic impact on the microstructures is still unclear. In this research, the effects of the mechanical and ultrasonic impact on the microstructures of the welded joint of 2195 Al–Li alloy are analyzed. It is found that the mechanical impact could not refine the grains, but the ultrasonic impact could refine the grains. The grains become smaller in the weld center with an increase in the ultrasonic amplitude. Possible mechanisms for the grain refinement are discussed. The results show that the small temperature gradient promotes formation of the equiaxed grain and the cavitation promotes heterogeneous nucleation.

Research about the Effect of Ultrasonic Impact on the Mechanical Property of Welded Butt Joint of P355NL1 Steel

Surface treatment was carried out on the butt joint weldment of P355NL1 steel by using the HJ-II-type ultrasonic impact machine. The ultrasonic impact current is 1.5A, the impact amplitude is 20 microns and ultrasonic impacting time is 5min. Tensile test was carried out for both treated specimen and un-treated specimen. The fracture observed with the scanning electron microscope of 6360LA type. The experimental results show that although the compressive residual stress can be obtained in the surface of weld toe area, and the grain size in the welded joint can be refined, but the mechanical property of the butt joint of P355NL1 steel can not be improved through the ultrasonic impact treatment. The main reason is that the ultrasonic impact layer is only 120um, it is to thin to compared to the thickness of the specimen.

Research about the Effect of Ultrasonic Impact on the Mechanical Property of Welded Cruciform Joint of P355NL1 Steel

Surface treatment was carried out on the welded cruciform joint of P355NL1 steel by using the HJ-II-type ultrasonic impact machine. The ultrasonic impact current is 1.5A, the impact amplitude is 20 microns and ultrasonic impacting time is 5min. Tensile test was carried out for both treated specimen and un-treated specimen. The fracture observed with the scanning electron microscope of 6360LA type. The experimental results show that although the compressive residual stress can be obtained in the surface of weld toe area, and the grain size in the surface of welded cruciform joint can be refined, but the mechanical property of the welded cruciform joint of P355NL1 steel can not be improved through the ultrasonic impact treatment. The main reason is that the ultrasonic impact layer is only 70um, it is to thin to compared to the thickness of the specimen.

Effects of Ultrasonic Impact Treatment on Performance of Armor Steel Welded Joints

In this paper, the armor steel welds were treated by ultrasonic impact equipment. The stress, hardness and cross section morphologies of the samples under different impact frequencies were measured by electrolytic polishing machines, X-ray stress analyzer and scanning electron microscopy (SEM). The results show that a clear grain refinement layer is formed on the surface of armored steel weld after ultrasonic impact treatment. Its hardness and residual stress all significantly improve. The ultrasonic impact treatment of different frequencies has greatly affect on ultrasonic impact effect, the higher the frequencies are, the better the ultrasonic impact effects are.

Research on High Volume Fraction SiC<sub>p</sub>/Al Removal Mechanism under Condition of Ultrasonic Vertical Vibration

High volume fraction SiCp/Al is a new kind of composite materials, with broad application prospect in the aerospace, automobile manufacturing and other fields, and gradually become the key materials in the field of high technology. But with its internal high hardness material (SiC) content increases and the material removal mechanism is not very clear, general machining is more difficult and seriously hinders the development of the material. With the advantages of high material removal rate, effectively processing all kinds of complicated curved surface, especially, in the thin-walled parts processing, milling occupies an absolute advantage. In order to solve the processing problems of high volume fraction SiCp/Al composites, basing on the theory of ultrasonic and brittle material removal. PCD milling experiment of SiCp/Al was carried out with homemade ultrasonic milling system under the condition of ultrasonic vertical vibration, the material removal mechanism was studied, the 2d and 3d model of surface formation was established, finally, microscopic structure on the surface of the workpiece was analyzed by metallographic microscope and electron microscope. Research results show that: SiC particle removal form can be divided into type of cut, pulled, pressed and crack penetration; under the condition of ultrasonic, probability of SiC particles cut type increased, this forms better surface smoothness; due to tool and chip separation characteristics and the ultrasonic impact effect on material, the removal mechanism of SiCp/Al is close to the plastic material, forming better surface quality under condition of ultrasonic. This paper verifies that the ultrasonic vertical vibration cutting is an effective machining method for high volume fraction SiCp/Al.

Review of Status about the Effect of Ultrasonic Impact on Fatigue Properties of Welded Joints of Magnesium Alloy

The study on magnesium alloy has attracted attention at home and abroad. Status and development trend about the fatigue properties of welded joints of magnesium alloy were reviewed. The main problems and deficiencies were pointed out, and the recent development's focus was outlined. The development trend of improving the fatigue propeties and fatigue life was analyzed. The ultrasonic impact method can not only decrease the stress concentration coefficient and tensile residual stress of welded joint, but also refine the grain size of welded joints, even to compressive stress and nanograins. The method has put forward a new way for increasing fatigue properties and life of welded joint of magnesium alloy.

Grain Refining Mechanism and Fatigue Properties of Bogie Welded Cruciform Joints Treated by Ultrasonic Impact

Surface treatment was carried out on the welded cruciform joint of 16MnR steel by means of ultrasonic impact treatment. The effect of ultrasonic impact on the fatigue properties of welded cruciform joint of 16MnR steel was studied. For comparison, fatigue experiments were carried out with both treated and un-treated specimens. The ultrasonic impact current was 1.2A, the impact amplitude was 30 microns. The grain refining mechanism was investigated using high resolution transmission electron microscope. The experimental results show that the fatigue performance of the welded cruciform joint of 16MnR steel is significantly improved through the ultrasonic impact treatment. The fatigue limit (2x106) of un-treated and treated joint is about 157MPa and 235MPa, respectively. Compared to the un-treated joint, the conditions of fatigue limit of the treated joint increased by 50% and the fatigue life increased 45-52 times. The equiaxed crystal nanostructured surface layers were fabricated on the surface of welded cruciform joint of 16MnR steel by ultrasonic impact, with the grain size being less than 100nm. The main reason for improving the fatigue performance is that the ultrasonic impact can reduce the stress concentration in the weld toe, decrease the tensile stress, and even change to compressive stress in the weldment, with the grain size in the welded joint being greatly refined. It indicates that ultrasonic impact treatment has remarkable effects on the fatigue life of 16MnR steel. Keywords: Fatigue strength, ultrasonic impact, grain refining, cruciform joint, 16MnR steel, transmission electron microscope, fatigue limit, crystal nanostructured surface

Research about the Effect of Residual Stress on the Fatigue Life of Cruciform Joint of 16MnR Steel

Surface treatment was carried out on the cruciform joint of 16MnR steel by using the HJ-II-type ultrasonic impact machine. The impact current is 1.2A, impact amplitude is 30 microns. Fatigue experiments were carried out for impact treated specimen, impact treated and heattreated specimen and un-heattreated specimen. The effect of ultrasonic impact on the hardness of the weldment and weld toe was researched. The experimental results show that the fatigue life of the cruciform joint of 16MnR steel can be significantly improved through the ultrasonic impact treatment and the hardness of weld toe can also be promoted. Compared to the sample without impact treatment, its fatigue life was increased 692.52%. The hardness of weld toe was increased 31%. Compared to the sample with heat treatment, the fatigue life of impact specimen was increased 316.67%. Compared to the sample without impact treatment, the fatigue life of impact and heat treated specimen was increased 218.69%.

Research about the Effect of Ultrasonic Impact on the Fatigue Life of Butt Weld Joint of 16MnR Steel

Surface treatment was carried out on the butt joint weldment of 16MnR steel by using the HJ-II-type ultrasonic impact machine. The ultrasonic impact current is 1.2A, the impact amplitude is 30 microns and ultrasonic impacting time is 30min and 60 min,respectively. Fatigue experiment was carried out for both treated specimen and un-treated specimen. The fatigue fracture observed with the scanning electron microscope of 6360LA type. The experimental results show that the fatigue life of the butt joint weldment of 16MnR steel can be significantly improved through the ultrasonic impact treatment. The main reason is that the ultrasonic impact can reduces the stress concentration in the weld toe, decrease the tensile stress, and even change to compressive stress in the weldment, the grain size in the welded joint can be refined. The longer the impact time, the greater increasing range of fatigue life will be. Compared to the sample without treatment, its fatigue life was increased 375.22%, 521.24%, respectively, when the impact time was 30, 60min, respectively.