Fracture Morphology Research Articles

Development and Evaluation of the OF Pelvis Score for Osteoporotic Pelvic Ring Fractures - A Retrospective Assessment of Therapy Recommendations for 107 Patients.

The aim of this study was to develop a simple and reliable score which supports decision making between non-operative and operative treatment in patients with osteoporotic pelvic fractures.Between 2018 to 2020, the OF Pelvis Score was developed during a total of 5 meetings of the Working Group on Osteoporotic Fractures of the Spine Section of the German Society of Orthopaedics and Trauma. The OF Pelvis Score as a decision aid between non-surgical and surgical treatment was developed by expert consensus after analysis of numerous geriatric sacral and pelvic ring fractures from several hospitals. Subsequently, retrospective evaluation of the score was performed on consecutive patients from three hospitals.The following parameters were considered relevant to decision making between non-surgical and surgical treatment and were incorporated into the score: fracture morphology using the OF Pelvis Classification, pain status, level of mobilisation, fracture-related neurological deficits, health status, and the modifiers already integrated into the OF Pelvis classification. If the score is <8, non-surgical therapy is recommended; if the score is >8, surgical therapy is recommended; if the score is 8, there is a relative indication for surgery. The OF Pelvis Score was then evaluated retrospectively in a total of 107 patients, according to records. The OF Pelvis Score was 8 points in 4 patients (3.7%), all of whom received surgical treatment. Of the remaining 103 patients, 93 received score-compliant therapy (90.3%). Among these, 4 of the patients who did not receive score-compliant care refused the recommended surgery, so the actual therapy recommendation was score-compliant in 94.2%.The OF Pelvis Score can be used to derive a therapy recommendation in many patients in clinical practice. Because of the possible change of clinical parameters during the course of the disease, the score has a dynamic character. In the retrospective evaluation, the recommendations from the OF Pelvis Score were in close accordance with the therapy actually performed.

Surgical management and results of glenohumeral combination fractures of the anterior glenoid rim and the proximal humerus.

The combination of anterior large glenoid rim fractures (GRF) and proximal humerus fractures (PHF) is rare, with limited data available on specific treatments for these glenohumeral combination fractures (GCF). This study aimed to evaluate the treatment approaches for GCF, analyze patient outcomes, and outline surgical management strategies for different fracture types. This retrospective study included patients with GCF, excluding those with fossa glenoidalis fractures, isolated greater tuberosity fractures, or small glenoid rim fractures (< 5mm). Preoperative radiographs, CT scans, and follow-up radiographs were reviewed. Clinical outcomes were assessed using the Constant-Murley Score (CMS), Western Ontario Shoulder Instability Index (WOSI), Rowe Score (RS), and Oxford Shoulder Score (OSS). Sixteen patients with 17 GCFs (mean age 62years) were followed for an average of 39months. PHFs were categorized into three-part (76%), four-part (12%), and two-part fractures (12%). The average medial displacement of GRF was 5mm, with an average dehiscence of 4mm in the sagittal plane. Fourteen patients (88%) underwent surgical treatment; 35% had only the PHF surgically addressed, while 53% had both lesions surgically treated. Two patients (12%) received non-operative treatment. Complications were observed in 29% of cases, primarily involving the humeral side. The average CMS was 68 points, WOSI was 75%, RS was 77 points, and OSS was 41 points. Treating GCF is complex and routinely necessitates surgical intervention, with or without GRF refixation. CT imaging is crucial for precise assessment of fracture morphology. The involvement of the minor tuberosity is critical in selecting the optimal surgical approach and managing the subscapularis muscle.

Does Femoral Stem Design Influence Periprosthetic Fracture Incidence and Morphology in Total Hip Arthroplasty?

BackgroundAs the incidence of total hip arthroplasty (THA) increases, the number of periprosthetic femur fractures (PFF) will also rise. The surgical approach and stem design have been shown to influence the rate of PFF. This study evaluated PFF in cementless THA done through the posterior approach and described how stem design influences intraoperative and early postoperative fracture incidence and morphology. MethodsA retrospective review of 3,183 primary THAs for osteoarthritis from 2013 to 2021 was performed. Demographics, comorbidities, femoral stem designs, intraoperative and early postoperative PFFs (< 90 days), and aseptic femoral revisions were recorded. Stems were classified as single-wedge taper (Type 1), double-wedge taper (Type 2), or ream and broach (Type 3). There were 1,192 Type 1, 240 Type 2, and 1,726 Type 3 femoral stems. The PFF and aseptic femoral revisions were compared with univariable and multivariable analyses. Cox regression and Kaplan-Meier analyses evaluated survival to femoral revision. ResultsIn this population, 25 patients (0.8%) had an intraoperative or early postoperative PFF. Patients who had PFFs were older (68 versus 63; P = 0.03) and more likely to be women (76 versus 24%; P = 0.02). Type 2 stems had a significantly higher incidence of all-cause PFFs when compared to Type 1 (3.6 versus 0.7%; P < 0.01) and Type 3 (3.6 versus 0.4%; P < 0.01) stems. Type 2 stems also had a higher incidence of Vancouver B2 PFFs when compared to Type 3 stems (0.8 versus 0.05%; P = 0.04). Stem design was not associated with PFF or all-cause femoral revision. There were no differences in survival to femoral revision. ConclusionDouble-wedge taper stems may be associated with increased intraoperative and early postoperative PFFs, including those requiring femoral stem revision. However, there was no statistically significant difference in late PFF, aseptic loosening, or femoral revision.

Aging performance and mechanism of carbon fiber-reinforced bismaleamide composites under natural aging in marine environments

The aging performance and mechanisms of carbon fiber reinforced bismaleimide composites under natural aging in marine environments are comprehensively investigated in this study. The prepared samples were exposed to aging under natural sunlight testing for one and a half years at the sea shores. Quasi-static tests were performed to evaluate the tensile, compressive, and in-plane shear strengths of the unaged and aged specimens. The fracture morphologies were characterized in order to reveal the aging mechanisms. The results show that the aging and decomposition of resin led to the reduction of mechanical properties. The 0° tensile, 0° compressive, 90° tensile and in-plane shear properties compared with unaged samples decreased by 4.6 %, 24.3 %, 24.7 % and 8.5 %, respectively. The microscopic, spectroscopic, and gravimetric analyses indicated that aging process mainly occurred on the surface of the specimen; the matrix degraded due to water hydrolysis, and the heat resistance of the samples decreased after aging. It was concluded that the autoclave molding method tightly combines the fibers with resin, making it more difficult for moisture to diffuse into the interior of the specimen. Based on the findings of this study, valuable insights can be made to guide the design, manufacture, and long-term durability of carbon fiber-reinforced bismaleimide composites in marine applications.

Ballistic properties of bioinspired nacre-like ceramic/polyurea staggered composite structures

We proposed a bioinspired ceramic/polyurea composite plate that draws on a “brick-mortar” arrangement of nacre layer, with a periodic three-dimensional structure and interlayers polyurea elastomers. We fired a 12.7 mm armor-piercing incendiary bullet using a ballistic gun to conduct depth-of-penetration (DOP) experiments. We analyzed the damage, fracture morphology, and residual DOP of ceramic/polyurea-staggered composite structures (CPSCS), with a theoretical prediction model for the residual DOP. Using the adaptive FEM-SPH algorithm, we compared the damage morphology of CPSCSs. We analyzed projectile penetration process and summarized four toughening modes using stress wave propagation. Based on simulation fitting and theoretical calculations, we obtained the residual DOP curves at different projectile velocities and analyzed the toughening effect of the CPSCSs through the energy dissipation of each structural component. When the areal density was the same, the residual DOP of the CPSCSs decreased by 33.9 %, and the critical velocity theoretically increased by 32.72 %. The error between the model calculations and experimental results was 11 %. The CPSCSs enabled the ceramic to increase the energy absorption efficiency by 179.70 %. With the same structural form, changing the thickness of only one component did not have the same effect on the structural energy-absorption efficiency as changing the entire form.

Study on Oil Resistance of Polyurethane Protective Material

Abstract The polyurethane protective tape is a new type of protective material made by coating high performance pressure-sensitive adhesive on polyurethane elastomers, which is widely used in aviation. During its operational life, the polyurethane protective tape inevitably comes into contact with oil, and its oil resistance directly impacts its lifespan. This study focuses on the polyurethane protective tape and conducts immersion tests in No. 15 aviation hydraulic fluid, aircraft gear oil 4450 and RP3 aviation kerosene at room temperature. A comparative analysis was also conducted on the tensile strength, tear resistance, fracture morphology, chemical structure, and thermophysical properties before and after immersion. The research indicates that the tensile properties of polyurethane protective tapes remain essentially unchanged after immersion in RP3 aviation kerosene. After being immersed in No.15 aviation hydraulic fluid and aircraft gear oil 4450, the tensile strength of the polyurethane protective tape gradually decreases. Furthermore, compared to No.15 aviation hydraulic fluid, the rate of tensile strength reduction in polyurethane protective tape immersed in aircraft gear oil 4450 is more rapid. The resistance to tearing of polyurethane protective tapes diminishes gradually with prolonged immersion, with the rate of decline being greater for aircraft gear oil 4450 than for No.15 aviation hydraulic fluid, and even greater for RP3 aviation kerosene. The decrease in mechanical properties of polyurethane protective tapes after immersion in oil is attributed to the swelling effect of the oil, which reduces the intermolecular forces within the polyurethane material and leads to a decrease in physical cross-linking. This process is physical aging, with no evident chemical aging occurring.

Effect of acid viscosity on conductivity during online acid-fracturing in ultra-deep carbonate reservoir

The influence of viscosity change in the same acid system on etched-fracture morphology and conductivity was often neglected in many studies that conducted multi-stages alternative acid-etching experiments using different acid systems. In order to address this knowledge gap, the present study investigated the impact of single injections of low viscosity and high viscosity acid, as well as an alternative stages of low and high viscosity acid, on the acid-etched fracture morphology and conductivity. While the online acid-fracturing technology was proposed based on experimental results firstly in ultra-deep wells. The results show that injecting acid with different viscosities is more effective than using a single viscosity acid-etching, as it improves fracture morphology and conductivity. Additionally, the stages of alternating acid have a significant impact on conductivity. Experimental studies reveal that employing three stages of alternating acid with different viscosities enhance the fracture conductivity in the research area. Based on these findings, the P6 well successfully is implemented online acid-fracturing in an ultra-deep well reaching 8000 m firstly in Sichuan Basin. Compared to adjacent wells, this technique exhibited lower friction resistance, enabling higher acid-injection rates.

Microstructure of ternary Sn-Bi-xCu alloy on mechanical properties, current endurance and corrosion morphology via cycling corrosion test

Low melting temperature of Sn-58 wt.% Bi (SB) solders adding 0.5wt.% Cu (SB05C) and 1.7wt.% Cu (SB17C) concentrations were evaluated for the signal transmission in the 3D IC package. Microstructure combined with phase analysis and Pandat simulation were together with to explain the relationship among the mechanical property, electrical endurance and corrosion resistance. By Cu decoration, the presence Cu6Sn5 intermetallic compound (IMC) acts as heterogeneous nucleation sites to reduce surface free energy and generate fine Bi grain that resulted in higher hardness value. The power-law was used to explain the mechanism of interfacial IMC growth, both Cu6Sn5 and Cu3Sn formation were speculated to be volume diffusion control and surface reaction domination, respectively. The fracture morphology by shear testing indicates that earliest plastic deformation accompanied with brittle rupture were major factors due to the intergranular fracture and Cu6Sn5 compound induced bulk fracture. By cycling corrosion test (CCT), the lump shape of SnO2 by-product was found among solders at three cycling. After seven cycling, Sn phase has been completely corroded and Cu6Sn5 IMC began to be corroded forming circle shape of Cu2O but Bi phase still not be corroded among solders. In the electrical endurance, dense Cu6Sn5 dispersed in solder bulk and fine grain size were feasible to induce current crowding and joule heating, thus Cu deteriorated SB solders is easily failed.

Intervertebral osteointegration and biomechanical performance of bioactive lithium disilicate glass-ceramic scaffold fabricated by digital light processing

The high strength of lithium disilicate (LD) glass-ceramic makes it difficult to form complex orthopaedic scaffolds using traditional methods. In addition, the osteointegration behavior of LD has also not been well studied in vivo. This study aimed to investigate the procedure of digital light processing (DLP) for fabricating porous LD glass-ceramic scaffolds and to assess the intervertebral osteointegration and biomechanical performance of the scaffolds. The phase formation, fracture morphology, flexural strength and density of LD glass-ceramics fabricated by DLP were evaluated to optimize the manufacturing process. Cell proliferation, cell differentiation and mineralization on the optimized glass-ceramics were recorded for comparison with traditional cast glass-ceramics (CG). The porous LD glass-ceramics scaffold was implanted into rabbits for 7 w and 14 w and then assessed using micro-CT and histological staining. Compression testing was also used to understand the scaffold’s mechanical properties. Furthermore, the scaffold was inserted into a validated finite element model of a human lumbar spine to study the stress distribution during physiological motions. The results indicated that LD glass-ceramics with step-by-step crystallization formed principal phases of Li2Si2O5 and Li3PO4, which had the highest flexural strength. Cell proliferation, cell differentiation and mineralization on the glass-ceramics formed by DLP were similar to the results of glass-ceramics formed by casting. The porous LD glass-ceramic scaffold promoted osseointegration in rabbits and was capable of withstanding physiological loads that would be experienced in a human lumbar spine. In conclusion, the bioactive LD glass-ceramic developed in this study showed good osteogenesis with sufficient mechanical performance, potentially making it suitable for applications in intervertebral fusion.

Intrafocal Pinning in Distal Extraarticular Radius Fracture: A Retrospective Study Based on Patient Age

Background: Percutaneous intrafocal pinning is one of the many surgical options for extraarticular distal radius fracture with minimal comminution. This study aims to describe the role and indications of intrafocal pinning. Methods: This monocentric, retrospective study included 49 patients who underwent intrafocal pinning for distal radius fractures in 2013 in our French hand surgery department. All the patients underwent posteroanterior and lateral x-ray on days 2 and 45 to measure radial inclination, distal radioulnar index, and volar tilt. Results: The mean age of the patients was 45.4 years, with women representing approximately 61.2% of the sample (n = 30). The patients were divided into three groups: group A (17–50 y), 26 patients; group B (50–70 y), 15 patients; and group C (&gt;70 y), eight patients. We documented on x-ray images, 21 secondary displacements, including seven in group C. There were three displacements (all in group C) and one surgical revision within 15 days for a previous displacement. The distal radioulnar index increased in all three groups. Conclusions: The percutaneous intrafocal pinning fixation technique exposes a high risk of complications, especially for those older than 50 years, for whom this technique should be avoided. Overall, due to the frequency of secondary displacements encountered, our first-line treatment favors plate osteosynthesis for all patients. Pinning fixation should only be considered with caution in younger patients if plate osteosynthesis is not possible, but it requires a strict 6-week immobilization. The fracture morphology must also be considered.

Laboratory investigation on fracture initiation and propagation behaviors of hot dry rock by radial borehole fracturing

Creating complex and interconnected fracture networks between injection and production wells is crucial for exploiting hot dry rock (HDR) geothermal energy. However, the simple planar fractures created by conventional hydraulic fracturing, primarily controlled by in situ stress, fail to connect directionally with the target well. This study proposes a novel stimulation method, i.e. radial borehole fracturing, which shows great potential for guiding the directional propagation of fractures. The fracture initiation and propagation behaviors of high-temperature granite under radial borehole fracturing are investigated and compared with those of conventional fracturing. Three-dimensional morphological scanning and reinjection tests are used to quantitatively evaluate fracturing performance. Additionally, the influences of key parameters, including rock temperature, in situ stress, injection rate, fluid viscosity, azimuth of the radial borehole, and the number of radial boreholes on the fracture morphology and breakdown pressure are investigated. The results show that radial borehole fracturing can effectively guide the initiation and propagation of fractures along the radial borehole. The breakdown pressure of radial borehole fracturing can be reduced by 14.1%-43.7% compared to conventional fracturing. A higher fluid-rock temperature difference reduces the directional propagation range of fractures guided by the radial borehole. Increases in the vertical density of radial boreholes, injection rate, and fluid viscosity enhance the guiding ability of radial boreholes. Furthermore, there is a competitive relationship between in situ stress and the azimuth of radial boreholes in controlling fracture propagation. This research provides a viable alternative for the directional connection of injection-production wells in HDR reservoirs.

Analysis of High and Low Temperature Performance of Titanium Zirconium Molybdenum Alloy and High Temperature Alloy Brazed Joint

Abstract Using niobium as the intermediate layer and gold nickel (Au82-Ni) filler metal, TZM alloy and high-temperature alloy GH3128 were brazed. The brazed specimens were subjected to 400 cycles of high and low temperature cycling tests at temperatures ranging from 650 °C ∼ 680 °C (high temperature) to -196 °C (low temperature) for 10 minutes seperately. Then the microstructure variation before and after the experiment were observed and the shear strength of the specimens were tested at room temperature for 50 cycles of 400 high and low temperature testing.. The results show that the microstructure of the transition zone at the brazing interface after brazing is uniform and dense, with good wettability with the substrate and no defects such as cracks. The solder and substrate undergo diffusion reactions, and the molybdenum alloy, niobium, and niobium, high-temperature alloy had each form diffusion layers, formed intermetallic compounds on the brazing surface. After high and low temperature cycling, cracks exist in the braze seam between molybdenum alloy and niobium alloy. The cracking mode should be thermal fatigue based on the fracture morphology and phase analysis. The reasons of interface cracking are that due to different thermal expansion coefficients, low mutual solid solubility, and the formation of a large number of different types of intermetallic compounds, Mo and Nb materials have poor brazing compatibility and lower interface strength. Under cold and hot cycling conditions, brittle intermetallic compounds are prone to form crack source areas. As the number of cycles increases, the cracks gradually expand, ultimately leading to product leakage. In addition, the shear strength of brazed joints shows a decreasing trend with the increase of high and low temperature cycles in 400 high and low temperature tests.

Clinical characteristics and outcomes of orbital fractures: a sex-based cohort analysis

PurposeThis study aims to identify clinical similarities and differences between males and females presenting with orbital fracture. MethodsPatient charts of adult orbital fracture cases diagnosed via computed tomography and referred by a level 1 trauma center to the McGill University Health Centre between August 2015 to January 2018 were examined and analyzed. Clinical parameters included age, sex, mechanism of injury, morphology of orbital fracture, symptoms and examination features, and rates of ocular pathology. Comparative analyses were performed via Student's t-test and chi-square to assess for sex-related differences. ResultsThe study included 176 males (mean age: 46.2 years) and 68 females (mean age: 58.5 years). The most common etiology of orbital fracture was assault among males (32%) and fall from own or standing height among females (38%). Males had a higher prevalence of bilateral fractures than females (17% vs 6%; p = 0.02) and had more orbital walls fractured per orbit than females (2.0 vs 1.5; p < 0.01). Males were more likely to have their orbital roof fractured (28% vs 15%; p = 0.03) and were more likely to be intubated after their trauma (22% vs 7%; p = 0.004). Post-traumatic ocular pathology occurred in 11% of males versus 9% of females (p = 0.56). ConclusionIn our cohort of adult orbital fractures, males were more prevalent, more likely to have bilateral fractures, more extensive fracture per orbit, and higher prevalence of orbital roof fractures and intubation. Despite these differences, rates of ocular pathology did not differ significantly between males and females, highlighting the importance of a careful assessment in both groups.

High temperature fatigue behavior of coated and uncoated nickel-based single crystal superalloy DD6: Microstructures evolution, damage mechanisms and lifetime prediction

Thermal barrier coatings (TBCs) are widely used to further extend the lifetime of turbine blades by protecting the blades from high temperature corrosion and oxidation. However, the mechanical behavior of turbine blades is obviously affected by the TBCs. In this study, microstructures evolution, damage mechanisms and life prediction of coated and uncoated nickel-based single crystal (NBSX) superalloy DD6 under isothermal fatigue load were investigated at 980 °C. The effects of TBCs on fatigue failure behavior and lifetime of DD6 were addressed. The results showed that the fatigue lifetime reduced with the increase of load. The effect of TBCs on the fatigue lifetime was related to the stress amplitude, as the effect was beneficial at high stress but almost negligible at low stress. Fracture morphologies showed that the cracks more likely initiated and propagated from basal defects for both coated and uncoated DD6, and the microstructure evolution also showed stress amplitude dependence. The crack density of uncoated DD6 increased first and then decreased with the increase of stress amplitude. However, the TBCs reduced the number of cracks that penetrate into the DD6 substrate, and the stress amplitude exerted a significant effect on crack propagation paths. In addition, the rafting behaviors of the DD6 substrate of coated and uncoated samples was compared, and results showed that TBCs could reduce the rafting degree of DD6. Finally, the fatigue lifetime of coated samples was predicted based on the modified Basquin model, and the prediction results fitted well with the experimental results.

Coupled effect of microstructure heterogeneity and hydrogen on local embrittlement of CGHAZ and IC-CGHAZ in X65 pipeline steel

The local embrittlement of the coarse-grained heat-affected zone (CGHAZ) and intercritically reheated CGHAZ (IC-CGHAZ) in X65 pipeline steel was investigated using an in situ crack-tip opening displacement test in air and H2S, combined with microstructure-based simulation. The IC-CGHAZ exhibited significantly lower cracking resistance, with the fracture toughness reduced by 50% compared to CGHAZ in both environments (0.160 mm in air and 0.017 mm in H₂S for IC-CGHAZ, compared to 0.307 mm in air and 0.034 mm in H₂S for CGHAZ). The martensite/austenite (M/A) constituents showed exceptionally higher intrinsic hardness than the ferrite matrix. The continuous distribution of M/As along the prior austenite grain boundaries resulted in local hardening and the formation of heterogeneous hard zones in IC-CGHAZ. Such microstructure heterogeneity resulted in the unique partitioning of plastic strain localization and stress triaxiality that promotes premature fracture, particularly with the coupled effect of hydrogen. This study provides a novel perspective on the fracture mechanisms and the typical fracture morphology of IC-CGHAZs in pipeline steel under the coupled effect of microstructure heterogeneity and hydrogen.

Synergistic effects of CO2 and H2S on stress corrosion cracking of stainless steel 254SMo in extremely aggressive oilfield environment

Synergistic effects of CO2 and H2S on stress corrosion cracking of stainless steel 254SMo in extremely aggressive oilfield environments were explored through experiments and water chemistry modelling calculations. Fracture morphology reveals transition from ductile fracture to plastic fracture characteristics. Initiation of fracture was attributed to pitting corrosion, and depth of the pits was consistent with the Gumbel distribution. Presence of CO2 and H2S exhibits a coupling effect on stress corrosion cracking of stainless steel 254SMo. Ionization of H2S promoted by CO2 produced more HS− and S2− with increasing temperature and pressure, accelerated pit generation on the surface, and increased susceptibility to stress corrosion cracking.

Influence of Heat Treatment on Microstructure and Mechanical Properties of Laser Cladding Coatings

This study investigates the influence of various heat treatment processes on the microstructure and properties of laser cladding Fe314 coatings. The microstructure, phases, and impact fracture morphology of the cladding layer were observed using X-ray diffraction and scanning electron microscopy, among other methods. The hardness and impact performance of the cladding layer were also tested. The results indicated that there was compositional segregation and non-equilibrium microstructure in the untreated cladding layer, with an average microhardness of 368.67 HV and an impact toughness of 27 J, exhibiting quasi-cleavage fracture. The stress-relief annealing treatment resulted in a uniform distribution of M23C6 carbides inside the cladding layer. The pinning effect generated by M23C6 reduced the microhardness by 16.26% and increased the impact toughness to 54 J. The impact fracture surface exhibited ductile fracture. After secondary normalizing and annealing, the microstructure of the cladding layer transformed into a fine single-phase austenite structure, and fine M7C3 carbides precipitated at the grain boundaries. Under the effects of fine grain strengthening and dispersion strengthening, the microhardness of the cladding layer decreased by 38.14%, and the average impact absorbed energy of the specimen was 64 J, showing complete ductile fracture.

Effect of solution and cooling methods on the high-temperature mechanical behavior of Ti60 alloy

The influence of solution treatment temperature and cooling rate on the mechanical behavior of Ti60 alloy at 600℃ was investigated. Five different solution treatment temperatures and five different cooling methods were used for the Ti60 alloy. The study revealed that, at the same solution treatment temperature the ultimate tensile strength (UTS) and elongation (Z%) of the water-quenched (WQ) microstructure were 32 % and 61 % higher, respectively, compared to the furnace-cooled (FC) microstructure. The WQ microstructure exhibited significantly superior strength and ductility. This phenomenon was primarily attributed to the differences in microstructural morphology caused by varying cooling methods. The effects of different cooling methods on high-temperature tensile behavior were discussed in terms of fracture morphology, high-angle grain boundaries, and void distribution. On the other hand, the UTS of the air-cooled (AC) microstructure initially increased and then decreased with decreasing solution treatment temperature, while the UTS of the FC microstructure decreased with decreasing solution treatment temperature. This phenomenon was mainly due to the competing effects of effective slip length (colony size) and elemental distribution. The correlation between solution treatment temperature and cooling rate parameters and high-temperature mechanical properties was established using the response surface methodology (RSM). The optimized solution cooling scheme was determined to be at 1012℃ with a cooling rate of 4238℃/min.

The fracture and perforation failure analysis of downhole tubes

：The downhole tubes were fractured and perforated after 5 years of shut-in due to high water cuts. This study employs a comprehensive array of analytical techniques to investigate the mechanisms behind fractures and perforations. Utilizing non-destructive testing (NDT), direct reading spectrometer, tensile strength testing machine, impact testing machine, optical microscope (OM), macroscopic fracture morphology observation, scanning electron microscope (SEM) and energy spectrum analysis (EDS), and sulfide stress corrosion cracking (SSCC) was studied. The reason for the fracture of the tubing is that under the condition of low pH value, high hydrogen sulfide environment, the tubing is fractured due to stress concentration caused by cracks in the outer thread relief groove. The perforation of the inner tube wall was caused by gradual wall thickness reduction under the influence of H2S, CO2, and Cl−, resulting in fouling and eventual perforation. To prevent tube corrosion during long-term shut-in, it is recommended to inject crude oil or diesel into the well.

Preparation of the fluorinated graphene/epoxy resin anti-corrosion composite coating

In order to enhance the corrosion resistance of epoxy resin (EP) coating system, we put forward a facile approach to prepare hydrophobic fluorinated graphene (FG) filler for the EP coating by one-pot hydrothermal reaction in this work. Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle measuring instrument and scanning electron microscopy (SEM) were employed for the FG characterization. The SEM images of fracture morphology revealed that FG uniformly dispersed in epoxy resin matrix. Additionally, the excellent water resistance and the lower coefficient of friction of FG/EP coating was confirmed through the water absorption test and friction and wear test machine. The electrochemical impedance spectroscopy (EIS) demonstrated that the impedance value at the low frequency (|Z|0.01Hz) of 0.50 wt% FG/EP was 3.49 × 107 Ω·cm2 after being immersed in 3.5 wt% NaCl solution for 60 days, which was about 2 orders of magnitude higher than that of the pure EP coating (4.74 × 105 Ω·cm2). The 0.50 wt% FG/EP coating exhibited the superior anti-corrosion performance due to the FG with the two-dimensional sheet structure, uniform dispersion and hydrophobicity properties.