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The thermal compression deformation behaviors of the hot extruded (HEX) FGH95 alloys were investigated systematically using the Gleeble 3800D thermal-mechanical simulator in the strain rate of 0.001~1.000 s−1 at the deformation temperature range of 1050~1120 ℃. The constitutive equations of the hot extruded FGH95 alloys were derived from the stress-strain curves obtained in the isothermal compression tests. Furthermore, the hot processing maps were established based on the dynamic models. In the results, the corresponding material constants of the constitutive equation are determined as Q=300.925 kJ·mol−1, α=0.01139 MPa−1, and n=1.86. Compared with the hot isostatic pressing (HIP) alloys, the activation energy of the hot extruded FGH95 alloys is declined by more than 50%. According to the energy dissipation efficiency and the microstructure analysis of the hot extruded FGH95 alloys, the processing safety zone and instability zone are identified during the hot extrusion process. Ultimately, the optimal processing conditions of the FGH95 alloys are proposed as the strain rate of 0.010~0.100 s−1 and the deformation temperature of 1050~1120 ℃.

In this paper, TWL12 + TWL20 inorganic salt aluminum coating was sprayed on the surface of Ni-based P/M superalloy. The microstructure changes of inorganic salt aluminum coating and P/M superalloy after high temperature oxidation at 700, 750 ℃ and 800 ℃ were studied by XRD, SEM, EPMA and TEM. The results show that after high temperature oxidation, the surface structure of the coating peels off, and the aluminum in the coating diffuses with the substrate to form a transition layer composed of oxidation zone, diffusion layer and interdiffusion zone. The oxidation zone is the outermost layer, where is mainly enriched with O and Al elements to form Al2O3 layer. The diffusion layer mainly contains Ni and Al elements, forming NiAl phase and α-Cr phase dispersed in it. Finally, the interdiffusion zone rich in Ti, Cr, Co, Ta and other elements exists between the diffusion zone and the matrix, which is mainly composed of Ni2AlTi phase matrix and σ phase dispersed in it. The analysis shows that the thickness of transition layer changes with the increase of oxidation temperature, it is mainly manifested by the increase of the width of the interdiffusion zone, the increase of the size of α-Cr phase in the diffusion layer and σ phase in the interdiffusion zone, and the growth trend of σ phase along the vertical transition zone is intensified. The oxidation weight gain curve shows that the transition layer exhibits good oxidation resistance during high temperature oxidation at 750 ℃ and 800 ℃ after the surface structure of the coating falls off, it indicates that the TWL12 + TWL20 inorganic salt aluminum coating has the potential to provide high temperature oxidation coating protection for advanced P/M superalloy used in aeroengines.

Effect of local interference (holding devices) on the surface microstructure of FGH96 alloys in quenching process was studied by optical microscope (OM), scanning electron microscope (SEM), electron probe microanalysis (EPMA), microhardness, and numerical simulation. The results show that, the holding devices used in quenching produce the chilling effect at the surface of FGH96 alloys, which changes the cooling mode of the connect points and then affects the precipitation and growth behavior of γ′ phases. After the low corrosion, the γ′ phases with the different size and morphology exhibit the visual color difference, leading to the corrosion circles. The maximum diameter of corrosion circles is ~10 mm, and the section depth is ~3 mm. The secondary γ′ phases inside the corrosion circles are fine and spherical, and the average size is ~100 nm. The secondary γ′ phases on the corrosion circles are polygonal distributed, and the average size is ~350 nm. The secondary γ′ phases outside the circles are spherical in distribution, and the average size is ~150 nm. The different size and morphology of the secondary γ′ phases result in the fluctuation of microhardness inside and outside the corrosion circles. The average microhardness is ~HV 450 outside the circles, and that of ~HV 485 inside the circles. The grain structure difference and the element segregation near the corrosion circles are not found.

In order to study the oxidation corrosion protection of key components of carrier aero engine, the high temperature oxidation behavior of the Ni-based powder metallurgy(PM) superalloys FGH4095 and FGH4096 in air at the temperature range of 750-1100 ℃ was investigated. The oxidation kinetics curves were determined by static weighing method. The structure, composition, and morphology of the surface oxide scale as well as its cross section were analyzed by metallographic microscope, scanning electron microscope (SEM), electron probe microanalyzer (EPMA) and X-ray diffractometer (XRD). The results show that two kinds of alloys belong to the grade of full oxidation resistance at 750-900 ℃ and oxidation resistance at 1000-1100 ℃. The actual service temperature of both alloys is below 900 ℃, so they exhibit excellent oxidation resistance in their operating temperature range.At 750-900 ℃, the oxidation resistance of the two alloys is similar without obvious difference. The oxide film is intact without peeling.The oxide films of FGH4095 and FGH4096 are composed of two layers after high temperature oxidation. The internal layer is mainly Al2O3.The outer layer of FGH4095 is composed of Cr2O3, Nb2O5 and TiO2. The outer layer of FGH4096 is composed of only Cr2O3 and TiO2.At 1100 ℃, both alloys are obviously oxidized and a large number of oxide scales crack. Due to the different compositions of the alloys, the oxidation resistance of the two alloys varies greatly at this temperature.In contrast, FGH4095 alloy exhibits better oxidation resistance.

The effect of forging temperature, strain rate and strain state on grain microstructure during solid solution heat treatment of extruded Ni-based Powder Metallurgy Superalloy was studied based on the heat-compression experiment of double cone (DC) specimens. The corresponding relationship between forging temperature, strain rate and grain microstructure in the range of forging temperature from 1060~1120 ℃ and strain rate from 0.003 s–1 to 0.3 s–1 was obtained. The results show that in the Double Cone compression experiment, at the same strain and temperature, the flow stress increases with the strain rate. And at the same strain rate, the higher the temperature, the lower the flow stress is. After supersolvus heat-treatment, at the same strain rate, the grain microstructure is inhomogeneous. And at the same forging temperature, the average grain size of the specimens under the three strain rates of three strain rate is 18~20 μm, but the specimens with higher strain rate clearly show inhomogeneous grain microstructures. In order to obtain the homogeneous grain structure, the more appropriate forging parameter is: the temperature of 1120 ℃, and the strain rate of 0.003 s–1. At the same forging temperature and strain rate, with the decrease of local strain, the average grain size is increased gradually.

Foreign non‐metallic inclusions can significantly reduce the low‐cycle fatigue (LCF) life of powder metallurgy (PM) superalloy and greatly affect the safety and reliability of aeroengines. In this paper, LCF experiments on PM FGH96 superalloy with and without inclusions were conducted. Effects of inclusions on the fatigue life and damage mechanism of FGH96 alloy are discussed by fractography analysis. Parameters related to inclusion characteristics such as strength–inclusion coefficient are proposed. By introducing characteristic parameters of inclusions, the LCF life prediction models are established based on the Manson–Coffin relationship, which significantly improved the prediction accuracy and reduced the scattering band by a factor of 2. Highlights: By performing strain‐controlled low‐cycle fatigue tests at different strain amplitudes, statistical analyses were carried out to assess the influences of size, location, and type of inclusions on LCF life, with a quantitative relationship established between them.The change law of LCF life of powder metallurgy superalloy under different inclusion conditions is summarized. Effects of inclusions on the LCF life of FGH96 alloy were clarified and applied to the establishment of fatigue life prediction models considering characteristic parameters of non‐metal inclusions.A modified Manson–Coffin life prediction model considering inclusion characteristics is proposed to support the safety and reliability assessment of turbine disks made of PM superalloy FGH96.By introducing characteristic parameters of inclusions, the LCF life prediction models are established based on the Manson–Coffin relationship, which significantly improved the prediction accuracy and reduced the scattering band by a factor of 2. [ABSTRACT FROM AUTHOR]

Background: Axial symptoms (AS) represent one of the primary complications after cervical spondylotic myelopathy (CSM) surgery. Traditional Chinese Medicine (TCM), as a complementary and alternative therapy, is widely used in the treatment of postoperative AS in CSM. However, it lacks standardised treatment protocols, uniform therapeutic criteria, assessment methods and a sufficiently in-depth understanding of its mechanisms of action. These shortcomings impact the credibility of TCM treatment in clinical practice., Methods and Analysis: We will conduct comprehensive searches, both manual and electronic, on literature published up to 31 July 2024, and database searches will commence after the publication of this agreement, with an estimated commencement date of 1 October 2024 and the end date of 31 March 2025, without language restrictions. Key databases such as MEDLINE, PubMed, Embase, Web of Science, Cochrane Library, WHO International Clinical Trial Registration Platform, China National Knowledge Network, China Biomedical Literature Database, China Scientific Journal Database and Wanfang Database will be explored. In addition, we will include resources such as library journals and conference abstracts. After identifying and screening all randomised controlled trials focused on TCM for postoperative AS of CSM, the two investigators will conduct a meta-analysis of the included studies. The results will be summarised as the risk ratio for binary data and the standardised or weighted average difference for continuous data., Ethics and Dissemination: Ethical approval is not required since this review does not involve individual patient data. The review's findings will provide clinicians with evidence on using TCM treatment for AS post-CSM surgery, disseminated through peer-reviewed publications or conferences., Prospero Registration Number: CRD42024505160., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Osteoporotic vertebral compression fracture (OVCF) is a common complication in elderly patients with osteoporosis. Despite undergoing percutaneous kyphoplasty (PKP) treatment, a significant percentage of OVCF patients (1.8% to 31.9%) continue to experience residual low back pain. While acupuncture has shown promise in relieving this pain, there is currently no systematic review on its efficacy specifically for residual low back pain after PKP in OVCF patients. This project aims to evaluate the effectiveness and safety of acupuncture as a treatment for this condition., Methods and Analysis: A comprehensive search will be conducted, including manual and electronic searches of literature published. Various databases such as MEDLINE, PubMed, EMBASE, Web of Science, Cochrane Library, International Clinical Trial Registration Platform, China National Knowledge Network, China Biomedical Literature Database, China Scientific Journal Database and Wan-fang Database will be explored. Additional sources like bibliographies and meeting minutes will also be searched. All randomised controlled clinical trials related to acupuncture for treating residual low back pain after PKP in OVCF patients will be included. Two researchers will independently perform study selection, data extraction and quality assessment. The primary outcome measure will be pain relief assessed using a visual analogue scale (VAS) or other validated scales. Secondary outcomes include effectiveness, Oswestry dysfunction index (ODI), quality of life questionnaire (QUALEFFO-41), follow-up relapse rate and adverse events. If feasible, a meta-analysis using RevMan V.5.3 software will be conducted. Otherwise, descriptive or subgroup analyses will be performed. Database searches will commence after the publication of this agreement, with an estimated commencement date of 1 August 2024., Ethics and Dissemination: Ethical approval is not required since this review does not involve individual patient data. The findings will be disseminated through peer-reviewed journals or relevant conferences., Prospero Registration Number: CRD42023478838., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)