Surface Fatigue Research Articles

FEM Investigation of the Roughness and Residual Stress of Diamond Burnished Surface

Characterization of surface integrity is possible with three critical metrics: microstructure, surface roughness, and residual stress. The latter two are discussed in this paper for low-alloyed aluminum material quality. Ball burnishing is a regularly used finishing procedure to improve surface roughness, shape accuracy, and fatigue life, taking advantage of the fact that it can favorably influence the variation in stress conditions in the material. The effect of burnishing is investigated using finite element simulation with DEFORM 2D software using the real surface roughness of the workpiece. The FEM model of the process is validated with experimental tests, the surface roughness is measured using an AltiSurf520 measuring device, and the residual stress is analyzed with a Stresstech Xstress 3000 G3R X-ray diffraction system (Stresstech, Vaajakoski, Finland). The results indicate that the burnishing process improves the surface roughness and stress conditions of AlCu6BiPb low-alloyed aluminum, and the study shows that there is good agreement between the FE and experimental results, further revealing the effect of the process parameters on the distribution of the compressive residual stress.

Application of Surface Ultrasonic Waves for Detection of Contact Fatigue Cracks in the Rail Surface

The integrity and durability of rails plays a key role in train safety. However, the interaction of the rail head surface with the wheels of the rolling stock leads to high damage to these areas. The surface of the rail head is subject to the greatest damage, in which fatigue cracks develop on the surface with subsequent development. Timely detection of fatigue cracks in the rolling surface is possible using the ultrasonic technique using surface waves. To do this, the work investigated the sensitivity of a surface ultrasonic wave to obstacles in the surface of rails in the form of extended grooves, notches of finite length and known depth, as well as real cracks. The studies were carried out using the pulse-echo method at frequencies of 1.25, 1.8, 2.5, 4 MHz. Research has shown that surface waves are sensitive to surface fatigue cracks. The amplitude of the reflected pulses depends on the wavelength and the depth of crack propagation. The influence of the distance to fatigue cracks and the orientation angle of the transducer relative to the rail axis on the sensitivity of the surface wave to these defects was also studied. The results obtained allow us to conclude that the use of surface ultrasonic waves makes it possible to detect fatigue cracks in the crack surface. Thus, the use of the pulse-echo technique and surface wave converters makes it possible to detect contact fatigue cracks in the rail head, which can be used to eliminate them in a timely manner. The determination of their depth by amplitude is influenced by many factors, which are difficult to take into account in real conditions.

Sustainable Diamond Burnishing of Chromium–Nickel Austenitic Stainless Steels: Effects on Surface Integrity and Fatigue Limit

This study aims to evaluate the influence of lubrication and cooling conditions in the diamond burnishing (DB) process on the surface integrity and fatigue limit of chromium–nickel austenitic stainless steels (CNASSs) and, on this basis, identify a cost-effective and sustainable DB process. Evidence was presented that DB of CNASS performed without lubricating cooling liquid satisfies the requirements for a sustainable process: the three key sustainability dimensions (environmental, economic, and social) are satisfied, and the cost/quality ratio is favorable. DB was implemented with the same values of the main governing factors; however, four different lubrication and cooling conditions were applied: (1) flood lubrication (process F); (2) dry without cooling (process D); (3) dry with air cooling at a temperature of −19 °C (process A); and (4) dry with nitrogen cooling at a temperature of −31 °C (process N). Conditions A and N were realized via a device based on the principle of vortex tubes. All four DB processes provide mirror-finished surfaces with Ra roughness parameter values from 0.041 to 0.049 μm, zones with residual compressive stresses deeper than 0.5 mm, and increases in the specimens’ fatigue limit (as determined by the accelerated Locati’s method) compared to turning and polishing. Processes F and D produce the highest microhardness on the surface and at depth. The process D introduces maximum compressive residual axial and hoop stresses in the surface layer. The dry DB processes (D, A, and N) form a submicrocrystalline structure with high atomic density, which is most strongly developed under process D. When high fatigue strength is required, DB with air cooling should be chosen, as it provides a more favorable cost/quality ratio, whereas dry DB without cooling is the most suitable choice for applications that require increased wear resistance.

Fatigue life prediction of cold expansion hole using physics-enhanced data-driven method

Cold expansion (CE) serves as a practical surface enhancement to improve the fatigue life of hole structures by improving surface integrity in both macro-scale and micro-scale. Due to the inaccessibility and high cost of experimental measurements, the physical relation between surface integrity and fatigue life are always implicit, serving as the major challenge for accurate life prediction. To address this issue, a novel method is proposed by introducing physical information to traditional data-driven method, where surface integrity enriched by multi-scale simulation is mapped to fatigue life via machine learning (ML) mechanism. As integrated to four typical ML algorithms, the proposed physics-enhanced data-driven method exhibit outstanding capability for accuracy improvement, decreasing the scatter band by amplitude between 27.3 % and 71.4 %. The proposed method offers a promising option for fatigue life prediction on surface treated structures with limited physical information.

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.

Failure of Universal 2 Wrist Joint Replacements: A Retrieval Study

Abstract Background The Universal 2 total wrist arthroplasty was one of the most common wrist replacements, but long-term results were disappointing, due to substantial damage to the polyethylene component and, in some cases, metallosis. The purpose of this research was to investigate the underlying reasons for this polyethylene damage. Methods From a single clinical center, retrieval analysis was undertaken on six Universal 2 wrists and two additional polyethylene components. All components were analyzed at the macroscale and dimensional measurements of polyethylene components were undertaken. These were compared against known component orientation in vivo to identify areas of greatest material loss. Results Of 62 Universal 2 wrists implanted, there was a tendency for smaller implants to be revised more frequently. Of the six explanted wrists, material loss was always noticeable on the ulnar side, and to a lesser extent in the dorsal direction. Five of eight polyethylene components had failed at the base of the ulnar-side blind hole. Smaller implants tended to have less thickness at the base of the blind holes, thus explaining the failure of smaller sizes. Discoloration and surface fatigue of explants indicated oxidation of components. Average time in vivo for the explants was 13.8 years which indicates the slow nature of polyethylene oxidation. All were revised due to loosening. All were implanted in rheumatoid patients with a mean age at surgery of 56.1 years. Three of the six Universal 2 wrists, all sized Extra Small, showed severe wear of the titanium alloy carpal component. Conclusion Failure of the polyethylene components was due to a combination of inappropriate sterilization technique plus a design issue where polyethylene was thinnest on the smallest size components. Continued surveillance of patients implanted with Universal 2 wrists is recommended.

Integrated detection for open and closed surface fatigue cracks utilizing scanning laser source-induced Rayleigh wave fields with self-reference peak-to-peak features

In this study, the integrated detection method for open and closed surface fatigue cracks is investigated. Firstly, the finite element simulation models are established to investigate the interaction between scanning laser source-induced Rayleigh waves and open and closed surface fatigue cracks, and the laser ultrasonic detection experiments are conducted for fatigue specimens containing fatigue cracks in different states. The simulation and experimental results indicate that the variation patterns in the peak-to-peak values of Rayleigh waves with horizontal scanning positions for open and closed cracks exhibit both similarities and differences. Subsequently, an integrated detection method based on self-referenced peak-to-peak features is proposed, which utilizes the similarities and differences to detect and distinguish open and closed cracks, respectively. Furthermore, this proposed method is experimentally validated, indicating that it can achieve accurate integrated imaging of open and closed cracks that have a high degree of agreement with the SEM images of the cracks. Additionally, the proposed method achieves a detection error of 2 % for the vertical lengths of the fatigue cracks. This study can provide guidance for integrated real-time detection of open and closed surface fatigue cracks of mechanical components in service.

Evolution of fretting wear behavior of zirconium alloy cladding tube under gross slip regime in simulated primary water of pressurized water reactor

The evolution of fretting wear behavior of zirconium alloy cladding tubes mated with dimples under the gross slip regime (GSR) was investigated. The findings revealed that the primary wear mechanisms under GSR were delamination, surface fatigue wear and abrasive wear, and the fretting damage rate mainly depends on delamination. The cross-sectional microstructure of the worn area could be divided into the third-body layer, tribologically transformed structure layer, and general deformation layer, with their formation mechanisms analyzed. Furthermore, the mechanism of wear-induced grain refinement was identified as dynamic recrystallization (DRX), including both continuous DRX and discontinuous DRX. Additionally, the processes of fretting wear and DRX were discussed.

The microstructure, mechanical properties and tribological behaviors of YB2C2 reinforced Cu matrix composites prepared by spark plasma sintering

The first ternary layered ceramic reinforced copper matrix composites, Cu-xYB2C2 (x = 0, 5, 10, 20 vol%) composites without interfacial reaction were successfully fabricated by spark plasma sintering at 950 °C. Microstructures, phase compositions, mechanical properties and tribological behaviors of Cu-YB2C2 composites were investigated. The results indicated that Cu-YB2C2 composites had good chemical compatibility. Compared with pure copper, the hardness, tensile strength and wear resistance of Cu-YB2C2 composites were all significantly improved. Cu-10 vol% YB2C2 composites exhibited the highest tensile strength and the best tribological performance, with an ultimate tensile strength of 203 ± 2 MPa and a wear rate of (3.1 ± 0.4) × 10−8 mm3/mm. The wear mechanism changed from adhesive wear to a combination of adhesive wear and abrasive wear with the addition of YB2C2, while surface oxidation and fatigue were also present in all tribosystems. Cu-YB2C2 composites have application prospects in electrical contacts and aerospace fields.

Influence of infill pattern and layer height on surface characteristics and fatigue behavior of FFF‐printed PEEK

AbstractPolyEther Ether Ketone (PEEK) is a leading thermoplastic biomaterial renowned for its exceptional overall properties and suitability for processing via Fused Filament Fabrication (FFF) Additive Manufacturing (AM). Despite its widespread use in industries, its fatigue behavior remains a critically underexplored aspect. This study aims to investigate the fatigue behavior of FFF‐produced PEEK, considering variations in infill pattern (triangular or rectilinear) and layer height (0.15 mm or 0.25 mm). Fatigue tests revealed a significant influence of the infill pattern on fatigue behavior, with the rectilinear pattern outperforming the triangular one. Layer height had a negligible effect when paired with rectilinear infill. Specimens with rectilinear patterns exhibited superior fatigue performance, achieving infinite fatigue life at maximum applied stress around 70% of ultimate tensile stress. Surface roughness assessment and fracture surface analysis at scanning electron microscope enhanced the interpretation of the results. This pioneering study lays the groundwork for future research in design for AM.

Effect of Ti, Mn and Mo on the microstructure and properties of CoCrFeNi high entropy alloy coatings prepared by laser cladding

CoCrFeNi-based High Entropy Alloys (HEAs) coatings, with additions of Ti, Mn, and Mo, were synthesized using laser cladding (LC). The pure CoCrFeNi HEA had a uniform FCC structure, exhibiting the lowest hardness and wear resistance but good corrosion resistance. The Ti-added HEA had an FCC+Laves+η phase structure, showing increased hardness and wear resistance due to abrasive and mild surface fatigue wear, though with the poorest corrosion resistance. The Mn-added HEA maintained a single FCC structure with coarser grain boundaries, exhibiting lower hardness and reduced wear resistance due to adhesive, abrasive wear, and minor surface fatigue wear, but with the best corrosion resistance.The Mo-added HEA developed a eutectic structure of FCC and σ phases, achieving the highest hardness and wear resistance due to oxidative wear, but showed moderately decreased corrosion resistance. The varying microstructures significantly impacted the coatings' mechanical properties and corrosion behavior, highlighting the critical role of alloying elements in customizing LCed-HEA coatings for specific applications.

Exploring the influence of ultrasonic peening treatment at ambient and cryogenic conditions on the surface characteristics and fatigue life of austenitic stainless steel 304L

This study investigates the impact of Ultrasonic Peening Treatment (UPT) at room temperature (Troom) and cryogenic temperature (Tcryo) on phase transformation, surface morphology, and fatigue life of stainless steel 304L samples. Finite element simulations were developed to analyze the effects of different material models and the pin's vertical velocity on residual stress, martensite volume fraction (ξ), and surface deformation. The numerical results of residual stress and ξ were consistent with experimental measurements obtained via X-ray diffraction. Significant compressive residual stress and martensite volume fraction were induced in the subsurface of the specimens following UPT at both temperatures. Various UPT process parameters, including static load, the pin's horizontal velocity, the number of treatments, and lubrication conditions, were experimentally explored for their effects on surface morphology and hardness. Indentation hardness revealed values of 621 HV for samples treated at Tcryo and 489 HV for those treated at Troom, compared to 286 HV for untreated specimens. Furthermore, UPT reduced surface roughness by approximately 88 % for a mechanically polished surface and over 93 % for a rough surface. Investigating conditions leading to potential damage and defects during the process was also undertaken. Fractography of the fracture surfaces and fatigue analysis revealed that the fatigue life of UPT-treated samples at Troom and Tcryo increased by 63 % and 45 %, respectively, compared to untreated specimens.

Study on the fatigue performance and Residual Stress of subsurface fluid flow of 2519a aluminum alloy based on water jet peening

In this study, the influence mechanism of water jet (WJ) strengthening on the surface integrity and fatigue properties of 2519 aluminum alloy was investigated by using finite element software Abaqus 2023 and fatigue analysis software Fe-safe. The effects of jet velocity and transverse velocity on the development of surface roughness and residual stress in different strengthening stages were studied, and the fatigue properties of WJ strengthened samples were analyzed by Fe-safe fatigue software. Finally, the fatigue life and fracture morphology of WJ strengthened specimens were analyzed by fatigue test, and the accuracy of finite element analysis was verified. Results indicate that surface roughness post-WJ enhancement displays a “W” shaped distribution, positively correlated with jet velocity. Conversely, increased roughness negatively correlates with higher traverse speeds, with optimal values recorded between 400 and 600 mm/min at WJ-290 mm/s, ranging from 1.10322 to 1.41167 μm. Additionally, the study reveals that maximum residual compressive stress during the WJ-Ip phase correlates positively with jet velocity, peaking at 302 MPa for WJ-290 mm/s. The research also notes that while higher jet velocities enhance residual compressive stress, they simultaneously elevate surface roughness, potentially introducing damage and increasing the variability of stress magnitudes. The study underscores the necessity of meticulously calibrating WJ parameters to enhance surface quality effectively while minimizing adverse effects. This balance is critical to optimizing the treatment process and achieving desired material properties.

Parameter Optimization of a Surface Mechanical Rolling Treatment Process to Improve the Surface Integrity and Fatigue Property of FV520B Steel by Machine Learning.

Surface integrity is a critical factor that affects the fatigue resistance of materials. A surface mechanical rolling treatment (SMRT) process can effectively improve the surface integrity of the material, thus enhancing the fatigue property. In this paper, an analysis of variance (ANOVA) and signal-to-noise ratio (SNR) are performed by orthogonal experimental design with SMRT parameters as variables and surface integrity indicators as optimization objectives, and the support vector machine-active learning (SVM-AL) model is proposed based on machine learning theory. The entire model includes three rounds of AL processes. In each round of the AL process, the SMRT parameters with relative average deviation and high output values from cross-validation are selected for the additional experimental supplement. The results show that the prediction accuracy and generalization ability of the SVM-AL model are significantly improved compared to the support vector machine (SVM) model. A fatigue test was also carried out, and the fatigue property of the SMRT specimens predicted by the SVM-AL model is also higher than that of the other specimens.

Influence of milling-finishing-shot peening hybrid machining on the surface integrity and fatigue performance of TC11 titanium integral impeller

Influence of milling-finishing-shot peening hybrid machining on the surface integrity and fatigue performance of TC11 titanium integral impeller

Study on surface integrity and fatigue performance of FeCoCrNiAl₀.₆ high-entropy alloy based on thermo-mechanical coordinated control

This study investigates the effects of various lubrication techniques on the surface integrity and fatigue life of FeCoCrNiAl0.6 high-entropy alloy during machining. By combining cutting experiments, fatigue tensile tests, and Abaqus/Fe-safe simulations, the research offers a comparative analysis of surface morphology, roughness, and fatigue life across different lubrication scenarios.The findings show a marked improvement in surface quality as cutting speed increases under all lubrication conditions. However, increased cutting depth generally leads to a decline in surface flatness. Specifically, surface roughness decreases with higher cutting speeds. For example, at 1200 m/min in dry cutting, the surface roughness is around 0.77 μm, which drops to 0.40 μm at 3000 m/min, representing a 48 % reduction. Under cryogenic minimum quantity lubrication (CMQL) at 1200 m/min, the roughness is 0.49 μm, decreasing to 0.25 μm at higher speeds, reflecting a 48.9 % reduction.However, increased cutting depth significantly deteriorates surface quality, with a notable rise in surface roughness values. Among the tested lubrication techniques, surface quality ranks as follows: CMQL > MQL > Dry.Regarding fatigue life, higher cutting speeds substantially enhance tensile cycle counts under all lubrication conditions. Specimens under CMQL achieved 2,000,042 cycles, compared to 1,238,520 cycles with minimum quantity lubrication (MQL) and 702,245 cycles in dry cutting—equating to 61.9 % and 35.1 % of the tensile cycle count for CMQL, respectively.Fatigue life decreases with greater cutting depth. For example, compared to a 0.2 mm cutting depth, tensile fatigue cycles decrease by 87.9 % for CMQL, 86 % for MQL, and 91.8 % for dry cutting at a depth of 0.5 mm.

Study on the effects of bilateral laser-assisted cutting on surface integrity and fatigue life of FeCoCrNiAl0.6 alloy

This study investigates the impact of various cutting parameters in both unilateral and bilateral laser-assisted cutting processes on the surface integrity and fatigue life of FeCoCrNiAl0.6 high-entropy alloy. By utilizing ABAQUS/FE-SAFE simulations and conducting laser-assisted cutting and fatigue tensile tests, differences in surface quality and fatigue life cycles of FeCoCrNiAl0.6 alloy samples under different cutting scenarios were evaluated. The results indicate that in high-speed laser-assisted cutting, an increase in laser speed leads to a progressive decline in surface quality for both unilateral and bilateral methods. Nevertheless, at a laser speed of 4000 mm/s, optimal surface quality is achieved in both approaches, with the bilateral method consistently providing superior results across varying speeds. Regarding residual stress, unilateral laser-assisted cutting at 4000 mm/s produces a surface residual compressive stress of 532 MPa, which is twice as high as that observed at 10000 mm/s. The bilateral method shows a symmetric distribution of residual compressive stress, with peak values of 567 MPa and 528 MPa on the front and back surfaces, respectively. In terms of fatigue life, bilateral laser-assisted cutting demonstrates enhanced performance at 4000 mm/s, achieving a fatigue life cycle that is 4.72 times longer than that of the unilateral method. Overall, bilateral laser-assisted cutting improves the fatigue life of the material through symmetric thermal effects and higher residual compressive stress, particularly at lower laser speeds and optimal cutting depths.

Effect of compound surface modification of shot peening and DLC coating on surface integrity and fatigue properties of gear steel 16Cr3NiWMoVNbE

We conducted a study on the surface compound modification of shot peening and pure carbon DLC coating to simultaneously meet the requirements of wear resistance and fatigue resistance of spline structure. The effects of surface compound modification were investigated on the surface morphology, residual stress profile, microstructure, and nano-indentation hardness of 16Cr3NiWMovNbE gear steel, and conducted a comparative study on fatigue performance. The results show that the surface compound modification inherits the surface morphology and compressive residual stress gradient of shot peening, while the surface residual stress is slightly smaller than that of shot peening. In addition, surface compound modification still reflects the characteristics of high hardness and high fracture resistance of DLC coatings. Under the bending load based on spline tooth root, compared to the original specimen, the fatigue life after shot peening, pure carbon DLC coating, and surface compound modification is increased by 3.68, 2.35, and 3.36 respectively. Although the compound modified surface still maintains the shot peening morphology with a increasing surface roughness and stress concentration coefficient, the 100 μm-depth compressive residual stress profile and the subgrain refinement layer introduced, as well as the hard surface layer with good load-bearing capacity, have played the role of fatigue strengthening.

Cutting performance and wear mechanism of submicron and ultrafine Ti(C, N)-based cermets

The complex thermal-mechanical coupling among Ti(C, N)-based cermet tool, workpiece and chip affects immensely the tool life, machining quality and costs during high-speed cutting, which makes the investigation on wear mechanisms of tools quite important. In this work, submicron and ultrafine Ti(C, N)-based cermet tools were prepared by vacuum sintering technology, and the cutting performance of the tools was evaluated by continuous dry cutting. The aim of this work is to unravel the wear mechanisms of submicron and ultrafine Ti(C, N)-based cermet tools based on the cutting performance and wear characteristics of both the cutting tools and chips generated during high-speed cutting. The Vickers hardness, flexural strength and tool lifespan of ultrafine Ti(C, N)-based cermets are significantly superior to those of submicron Ti(C, N)-based cermets because of grain refinement strengthening and the improved distribution of metal phases. Tool wear depends to a large extent upon the contact states and heat transfer ability at different locations of the tool edge, which are characterized by simultaneous action and mutual transition from abrasive, adhesion, surface fatigue and oxidative wear. Overall, ultrafine Ti(C, N)-based cermet tools with excellent comprehensive properties exhibit a distinctly reduced tool wear at different wear regions.

Investigation of surface finish and fatigue life of laser Powder Bed fused Ti-6Al-4V

In this fact-pacing world of technological advancement, the rise of additive manufacturing (AM) has found immense applications of metallic alloys such as Ti6Al4V to manufacture key components in automotive, aerospace and healthcare sectors. However, fatigue characteristics of such additively manufactured metal alloys is noticeably weak, and as such requires post-processing. In this study, AM Ti6Al4V manufactured by Laser Powder Bed Fusion (L-PBF) was treated by Hydrodynamic Cavitation Abrasive Finishing (HCAF) and Laser Cavitation Peening (LCP) to observe the improvement in surface roughness as well as fatigue performance. Our investigations revealed a substantial improvement in surface quality post-HCAF processing. Notably, the surface roughness of AM Ti6Al4V specimens showed a significant reduction of about 91.2 %, post surface treatment. However, Laser Cavitation Peening (LCP) treated sample demonstrates a significantly enhanced fatigue strength of 393 ± 22 MPa at 107, which was 1.75 times better than that of as-built one, i.e., 224 ± 16 MPa. This difference can be attributed to the distinct surface modification mechanisms of each technique. LCP, utilizing laser-induced shock waves, likely induces large compressive residual stresses, leading to better fatigue resistance.