Ultrasonic Surface Rolling Research Articles

Effect of ultrasonic surface rolling process on the fatigue performance of the 7075 aluminum alloy

Effect of ultrasonic surface rolling process on the fatigue performance of the 7075 aluminum alloy

Effect of ultrasonic surface rolling process by disparate static pressure on a carburized layer of 17CrNiMo6 steel

Considering the elevated application requirements for transmission gears in terms of wear and corrosion resistance, this study investigates the impact of different static pressures (0.4 MPa, 0.6 MPa, 0.8 MPa) on the structure and protective properties of vacuum-carburized USRP layers, leveraging the technical advantages offered by vacuum carburizing and USRP. The findings demonstrate that using USRP facilitates fine-grained strengthening, and the thickness of the grain refinement layer increases proportionally with static pressure. The 0.6 MPa static pressure exhibits the most pronounced positive impact on grain refinement. The application of varying static pressures results in different surface integrity and microhardness levels within the carburized layer, thereby impacting the layer's wear and corrosion resistance. The coating exhibits the highest hardness and lowest roughness at a static pressure of 0.6 MPa, thereby demonstrating superior wear resistance. In addition, the 0.6 MPa layer with the lowest roughness has the best corrosion resistance.

Surface fatigue characterization and its enhancement by the engineered ultrasonic rolling process for 300 M ultrahigh strength steel

The fatigue life of surface layer (FSL) is innovatively characterized to accurately capture the effect of surface integrity on the fatigue behavior of the components. The sensitivity of FSL of 300 M ultrahigh strength steel to the surface integrity indexes induced by representative manufacturing processes was analyzed by analytical modeling and fatigue tests from the perspective of engineering fracture mechanics. The ultrasonic surface rolling process (USRP) was introduced to optimize the fatigue limit of 300 M steel, and the improvement in fatigue life was experimentally quantified. Besides, the fracture analysis was conducted to provide the reason why USRP can enhance the fatigue behavior of 300 M steel. The results show that FSL occupies a majority with percentage of over 95 % in the entire fatigue life and a strong relation with the machined surface defects, especially the surface machining marks. The excellent surface finishing effect and high compressive residual stresses induced by engineered USRP could transfer the crack source from surface machining marks into subsurface inclusions, which greatly prolongs the fatigue crack initiation life and thereby the entire fatigue life. To be specific, the fatigue life was elevated by more than 40 times and the fatigue strength was increased by 34.7 % after USRP for the tested 300 M steel.

Effect of ultrasonic surface rolling on the microstructure and mechanical properties of 2195 Al-Li alloy fabricated by laser powder bed fusion in various build directions

To address the challenges of poor forming quality in the laser additive manufacturing of lightweight alloys, this paper explores an approach that integrates a laser additive manufacturing strategy for lightweight alloys with surface deformation strengthening. The study investigates the combined effects of build direction (BD) and ultrasonic surface rolling (USR) on the microstructure, residual stress, and mechanical properties of 2195 Al-Li alloy processed by laser powder bed fusion (LPBF). The results indicate that changes in BD significantly affect the growth direction of columnar grains (CGs) in the formed specimens and lead to the formation of a gradient microstructure with different characteristics under the influence of USR. When BD is 0°, the post-USR specimen exhibits the most significant deformation strengthening effect, with the high dislocation density reaching depths of up to 720 μm and compressive residual stress amplitudes up to −159 MPa. When BD is 90°, the sample shows excellent tensile performance with an ultimate tensile strength (UTS) of 386 MPa and an elongation (EL) of 8.2 %. After USR treatment, the UTS of the sample increases to 438 MPa, but the EL decreases to 5.1 %. CGs exhibit varying deformation resistances in different directions, thereby influencing the deformation strengthening effect of USR and altering the crack propagation mechanism during the tensile process.

Quantitative mechanism of abnormal hardening behavior of Ti6Al4V alloy strengthened by ultrasonic surface rolling

In general, the outermost region of a metallic material has the highest hardness after surface mechanical strengthening. However, an abnormal surface hardening behavior was observed in Ti6Al4V alloy after the ultrasonic surface rolling process (USRP) in this work. The region with the highest surface hardening was not at the top surface but at the subsurface. By analyzing the distribution of grain size, dislocation density, texture, and kernel average misorientation (KAM) at different depths from the surface, and combining these findings with finite element analysis (FEA), the microstructural evolution underlying this abnormal surface hardening was elucidated. The microstructural characterization and FEA results indicate that the subsurface region underwent the most significant deformation. Subsequently, through the application of theoretical analysis, the potential mechanism of abnormal hardening of USRP treatment is described quantitatively for the first time. The results demonstrated that the hardening effect resulting from grain refinement was less pronounced, whereas the hardening effect resulting from dislocation pile-up was more prevalent. At the subsurface region of the USRP sample, a large number of interfaces resulted in the highest accumulation of dislocations in this area. Consequently, the subsurface region exhibited the highest microhardness, leading to the abnormal surface hardening phenomenon.

Deformation mechanism of Ni-based single crystal superalloy under ultrasonic surface rolling and subsequent thermal exposure

In present work, ultrasonic surface rolling (USR) is applied to DD6 Ni-based single crystal (NBSC) superalloys, and the thermal relaxation behavior of the pre-treated alloys are investigated at 650 °C. Combined with mechanical properties, the plastic deformation and recovery mechanisms of the hardened layers are revealed in detail. Results show that compressive residual stress amplitude of 1163 MPa, 75.1 % improvement of surface nano-hardness and 83.02 % reduction on surface roughness are achieved by USR. Both deformed layer thickness and slip density progressively increases with USR cycles, where initial octahedron {111}<110> slips transform to a mixture of octahedron {111}<110> and dodecahedron {111}<112> slips. Meanwhile, shear step length expansions form γ′ segment/γ terminal interface with superlattice extrinsic stacking fault (SESF) on 1¯11, which may have inferior energy threshold for γ dislocation invasions than primary ones through shortening mean free path. Also, this drives γ′/γ solute mingling to induce tortuous interfaces. While dislocation proliferation dominates γ channel hardening, the γ′ hardening derives from planar fault strengthening and net system energy augmentation. During thermal exposure, surface integrities of USRed DD6 are strongly degraded, attributable to slip trace elimination and local γ′ coarsening. Thermal exposure further compels the γ dislocation to migrate towards γ′ segment across γ′ segment/γ terminal interface. Then, they are probably consumed to motivate solutes to phase boundary to reshape the γ′ morphologies through interface rearrangements under the assistance of γ dislocation network. The orientation transformation of SESF on 1¯11 to 010 and the mixture of SESF and superlattice intrinsic stacking fault on 1¯11 are thought to be possible manipulated mechanisms for γ′ coarsening, significant impairing the work hardening of alloy due to interfacial coherency deterioration. This paper could provide guidance for USR strengthening designs of NBSC.

The Effects of Different Ultrasonic Composite Surface Modifications on the Properties of H13 Steel for Shield Tunnel Machine Cutter Ring

Tunnel boring machines (TBMs) are exposed to the impact of the ground shattering force and the friction of sandstone during excavation work, and are prone to wear and breakage, and other failures. Traditional heat treatment processes cannot simultaneously achieve the required high-energy composite structure of hard external and tough internal properties for cutter rings, leading to inadequate wear resistance and impact toughness under working conditions. This study utilizes H13 steel as the base material, and based on a study of carburizing, nitriding, and ultrasonic impact processes for H13 steel analyzing the effects of different high-energy composite modification processes on the hardness distribution, microstructure, and residual stress of H13 steel, the mechanisms by which high-energy composite modification processes affect the wear resistance and impact resistance of H13 steel are revealed. The results indicate that the wear amount and impact toughness of the sample subjected to carburizing and ultrasonic surface rolling composite strengthening were 1.9 mg and 27.34 J/cm2, demonstrating the best wear and impact resistance. This combination of properties allows the H13 steel cutter ring to achieve the optimal overall performance in terms of wear resistance and impact resistance.

Effect of Ultrasonic Surface Rolling on the Microstructure and Corrosion Properties of Gear Steel 20CrNiMo After Carburizing

Effect of Ultrasonic Surface Rolling on the Microstructure and Corrosion Properties of Gear Steel 20CrNiMo After Carburizing

Gradient residual stress evolution and its influence on fatigue life under combined carburising heat treatment and ultrasonic surface rolling process

This study combined carburising heat treatment (CHT) with the ultrasonic surface rolling process (USRP) to improve the rotary bending fatigue properties of 18CrNiMo7-6 alloy steel. Based on the experimentally obtained fatigue limit (σ-1), the evolution of gradient compressive residual stress (CRS) of CHT- and CHT + USRP-treated specimens was analysed below the fatigue limit stress level. Subsequently, the evolution mechanism of gradient CRS of the two reinforced specimens was discussed and analysed from the opposing effects of austenite transformation and dislocation density change on the evolution of CRS. The results demonstrated that the selective bending fatigue performance of the alloy was evidently improved after the introduction of CRS; however, the change in fatigue limit was not evident. The durability under other loads (such as cyclic tension/compression and torsion loads) needs further study. The gradient CRS evolution of CHT specimens was mainly caused by the large residual austenite transformation and small dislocation density change. Therefore, the volume expansion caused by residual austenite transformation gradually increased the gradient compression residual stress of CHT specimens with an increased number of cycles. Contrarily, the degree residual stress evolution of CHT + USRP specimens was more affected by the dislocation density, and the gradient compression residual stress gradually decreased with an increased number of cycles. Finally, the residual stress evolution rate of the two reinforced specimens was divided into two stages: fast and slow.

Effects of the Ultrasonic Surface Rolling Process on the Surface Integrity, Wear Resistance, and Corrosion Resistance of 4Cr5MoSiV1 Tool Steel Before and After Quenching

Effects of the Ultrasonic Surface Rolling Process on the Surface Integrity, Wear Resistance, and Corrosion Resistance of 4Cr5MoSiV1 Tool Steel Before and After Quenching

Microstructure evolution and surface strengthening behavior of 300 M ultrahigh strength steel under engineered surface treatments

In this work, the most efficient and common engineered surface treatments identified as shot peening (SP), laser shock peening (LSP) and ultrasonic surface rolling process (USRP) were utilized to impact the 300 M ultrahigh strength steel. The microstructure evolution and surface strengthening behavior were carefully characterized and compared for the 300 M steel with various treatments. Besides, the underlying mechanisms for difference in grain refinement and surface mechanical properties by the arranged surface modification are revealed. The results indicate that a gradient structure with nano-grains at the top surface appears on the SP, LSP and USRP treated samples. The process of repeated impacts of SP in different directions leads to activation of multiple slip systems, which thus causes severe refined grains and dense dislocation activities associated with dislocation tangles, dislocation walls and blocking. A great variety of strikes per unit area by USRP results in higher plastic deformation compared to SP where numerous dislocation cells and deformation bands were generated. In contrast to SP and USRP, fewer slip systems are activated in LSP due to the short duration time which thus leads to the thinnest refined grain layer and more planar dislocation structures. The combination of low plastic work and lack of refined grains leads to lowest full width at half maximum (FWHM) in case of LSP samples whereas high FWHM comes from both fine grain size and dislocations in SP. The grain refinement and plastic work contributes to an increase of microhardness and compressive residual stress for the SP, LSP and USRP samples. To be clear, SP leads to a higher magnitude of hardness and compressive residual stress on the topmost surface while LSP causes a larger depth due to that shock wave in LSP influences material to much greater depth. Besides, the decomposition and redistribution of carbides are also noticed on the surface layer after the surface treatments with very high strain rate where numerous dislocations accumulate at the border of the carbides and slip trace is also observed within the carbides.

Enhanced strength-plasticity synergy of 304 stainless steel by introducing gradient nanograined single austenite phase structure via USRP and induction annealing

The drawback of low strength of 304 stainless steel could be overcome by fabricating gradient nanostructures (GNS). However, deformation-induced martensite results in magnetic generation and plasticity degradation. In this work, a single austenitic GNS 304 stainless steel is fabricated by first creating a dual-phase GNS through the ultrasonic surface rolling process (USRP), followed by rapid induction heating. The yield strength of the single austenite GNS (520 MPa) is 1.68 times higher than that of the homogeneous coarse-grained structure (310 MP) without sacrificing plasticity (elongation of 65 %). Quantitative calculations indicate that fine grain, dislocation, twinning, and back-stress strengthening contribute to the strength increment by 30 %, 17.5 %, 23.4 %, and 29.1 %, respectively. Coarse-grained regions deform mainly through FCC-HCP-BCC martensitic transformation, whereas the subsurface layer forms stacking faults and twins due to increased stacking fault energy caused by the reduction in grain size. At the topmost layer, the stress required to activate dislocations is lower than that for twinning. Under high-stress conditions, martensite forms along the nanograin boundaries via a phase transition from FCC to BCC. Consequently, the excellent plasticity of the single austenite GNS stems from the synergistic effects of high back-stress hardening, TRIP and TWIP effect.

Corrosion evolution of 316L stainless steel after ultrasonic severe surface rolling and laser shock peening processing

Laser shock peening induced smaller grain size than ultrasonic severe surface rolling for 316L stainless steel. Furthermore, laser shock peening processing facilitated to induce more strain induced α′-martensites. Therefore, the refined grains and α′-martensite enhanced significantly the hardness of 316L stainless steel. Moreover, laser shock peened sample exhibited better corrosion resistance than ultrasonic severe surface rolled one in a medium containing chloride ions. Although α′-martensite would decrease passivation and anti-corrosion ability of 316L stainless steel, the grain refinement promoted the diffusion activity of chromium element, which accelerated surface passivation process.

Effect of corrosion on the fatigue damage behavior of M50 steel treated by ultrasonic surface rolling process

Ultrasonic surface rolling process (USRP) can improve the fatigue performance of M50 steel, but corrosion during service may affect the anti-fatigue performance. Microstructure and corrosion resistance of M50 steel treated by USRP is analyzed by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS). Besides, the fatigue behavior of USRP sample under corrosion is analyzed by conducting fatigue tests after immersion corrosion tests. Results show that USRP treatment refines the surface grains to nanoscale (29.8 nm), introduces a certain residual compressive stress and decrease the precipitations of M50 steel, which improve the density of passive film and the resistance to local corrosion for M50 steel. Compared to M50 steel matrix, USRP sample has fewer and smaller corrosion pits at the same corrosion time, thereby reducing the risk of crack initiation. Meanwhile, the residual compressive stress value of USRP sample remains at a higher level. So the fatigue life of USRP sample is always higher than that of untreated sample under the same corrosion time. However, the corrosion process still leads to the destruction of surface integrity and the release of residual compressive stress, and the fatigue performance of USRP sample will gradually decrease with increasing the corrosion time.

Study of Quenching and Partitioning (Q&P) and Ultrasonic Surface Rolling (USR) Process on Microstructure and Mechanical Property of a High-Strength Martensitic Steel.

Steel with a combination of strength and plasticity is prevalently demanded for lightweight design and emission reductions in manufacturing. In this study, a high-strength Cr-Ni-Mo martensitic steel treated by quenching and partitioning (Q&P) and ultrasonic surface rolling (USR) processes was studied for both strength and plasticity enhancement. Specimens were austenitized at 850 °C and then quenched to 240 °C via cooling by water, oil, and normalization in quenching. This was followed by partitioning, in which two groups of specimens were heated to 370 °C and 350 °C for 45 min, respectively. At last, all the specimens were quenched to room temperature with the same methods of quenching. The highest tensile strength increased from 681.73 MPa to 1389.76 MPa when compared to as-received (AR) steel after the Q&P process. The USR process with a static force of 800 N further improved the tensile strength of specimens with high tensile strength after the Q&P process, which improved from 1389.76 MPa to 1586.62 MPa and the product's strength and elongation (PSE) increased from 15.76 GPa% to 15.9 GPa%, while the total elongation showed a mitigatory decrease from 11.34% to 10.02%. Tensile fractures were also studied and verified using a combination of strength and plasticity after a combined process of Q&P and USR.

Reconstruction Mechanism of Surface Integrity for Laser Additive Manufactured 316 L Stainless Steel Subjected to Ultrasonic Surface Rolling Process: Numerical Simulation and Experimental Verification

Reconstruction Mechanism of Surface Integrity for Laser Additive Manufactured 316 L Stainless Steel Subjected to Ultrasonic Surface Rolling Process: Numerical Simulation and Experimental Verification

A FEM-guided data-driven machine learning model for residual stress characterization in ultrasonic surface rolling of lightweight alloys

A FEM-guided data-driven machine learning model for residual stress characterization in ultrasonic surface rolling of lightweight alloys

Surface integrity and rolling contact fatigue behavior of 18CrNiMo7-6 steel subjected to ultrasonic surface rolling process

In this study, the effect of ultrasonic surface rolling process (USRP) on the surface integrity and rolling contact fatigue (RCF) behavior of 18CrNiMo7-6 steel have been conducted. The different static loads and ultrasonic amplitudes on surface morphology, surface roughness, microstructure, microhardness, and residual stress were examined. Results revealed that USRP treatment resulted in a remarkably smooth surface with the surface roughness value Ra of 0.035 μm. Moreover, USRP treatment induced the formation of nanocrystalline and ultrafine crystalline structures on the surface layer. Additionally, the sample surface was subjected to a significant layer of residual compressive stress, reaching a maximum value of approximately −1243 MPa and extending to a depth of around 1500 μm. The surface microhardness had been increased to 808 HV0.2. The comprehensive integration of grain refinement, the increase of surface microhardness, and the induction of residual compressive stress led to an improvement in RCF life.

Enhancing wear resistance of laser-clad AlCoCrFeNi high-entropy alloy via ultrasonic surface rolling extrusion

The AlCoCrFeNi high-entropy alloy (HEA) coating was synthesized by laser cladding and subsequently processed by ultrasonic surface rolling extrusion (USRE) with varying static loads of 100 N, 200 N, and 300 N. This study aimed to explore the effects of static load on the microstructure, mechanical properties, and tribological characteristics of the coatings. The findings indicate that increased static load results in the precipitation of martensitic phases, grain refinement, enhanced microhardness, and an elevated dislocation density. Specifically, after USRE with 300 N static load, the coating's microhardness reaches 753 HV, 1.4 times greater than the un-USRE coating. This enhancement is attributed to the synergistic effect of martensite phase transformation, grain refinement, and dislocation strengthening. The volume wear rate of the coating decreases to 1.31 × 10−4 mm3·N−1·m−1 following USRE at 300 N, demonstrating superior resistance to abrasive wear due to the high microhardness. Besides, the high-density dislocations facilitate rapid migration and diffusion of oxygen elements, thereby enhancing the oxide layer's protective properties and improving the coating's resistance to oxidation wear.

Surface Properties and Fatigue Behavior of 6061 Aluminum Alloy by Multi-pass Ultrasonic Surface Rolling Process

Surface Properties and Fatigue Behavior of 6061 Aluminum Alloy by Multi-pass Ultrasonic Surface Rolling Process