最新刊期
卷 46 ， 期 4 ， 2025
- 摘要：The research progress and development status of ultra-supercritical steam turbine blade steels and alloys are reviewed. According to the different operating environments， blade materials can be classified into high-temperature blades and last-stage large blades. For high-temperature blade materials， 9% to 12% ferritic heat-resistant steels are used in 600 ℃-620 ℃ ultra-supercritical power plants in operation. For steam parameters above 630 ℃， the thermal stability of iron-based materials is insufficient， and nickel-based heat-resistant alloys need to be selected. The world's first 630 ℃demonstration unit selected 80A blade alloy. Nickel-based blade alloys for steam parameters above 700 ℃are still in the research and development stage. The candidate materials in various countries are all γ' precipitation-strengthened nickel-based alloys，and China has developed the W/Mo composite-strengthened GY200 nickel-based blade alloy. Last-stage large blades can be divided into 12%Cr martensitic steel， high-Cr precipitation-strengthened stainless steel， and titanium alloys. The new generation of last-stage blade steels， 2Cr12Ni4Mo3VNbN and B50A789G， have a better strength-toughness match and will gradually replace traditional 12%Cr martensitic steel and 17-4PH blade steel， being applied in high-power units. The relationship between composition， microstructure， and properties of the most widely used ferritic （martensitic） blade steels is summarized from aspects such as composition control， secondary remelting， forging billet， and final forging forming process， as well as the key control technologies in the production process. Suggestions and prospects for the development of blade steels are proposed. In the next 10 years， for ferritic （martensitic） blade steels， low-cost purification smelting technology and batch quality stability control technology will be the main development directions. For 700°C nickel-based blade alloys， domestic research and development of materials and products are underway and will become the main development direction in the field of blade materials. It is expected that a technological breakthrough will be achieved by 2030， and self-developed blade alloys and products will be developed.关键词：Ultra-supercritical Steam Turbine;Blade Steel and Alloy;9%-12%Cr Ferritic Steel;Nickel-based Blade Alloy45|6|0更新时间：2025-09-02
- 摘要：Nickel/nickel iron-based alloys are widely used in the manufacturing of hot end components for aircraft engines， gas turbines， advanced ultra-supercritical power plants， and other equipment due to their excellent oxidation resistance/corrosion resistance and high-temperature mechanical properties. Phosphorus （P） microalloying is one of the effective ways to improve their high-temperature creep strength and increase creep fracture life while maintaining the same main elements contents. P has extremely low solubility and low activity in nickel/nickel iron-based alloys. During solidification process， it is easy to accumulate at the front of the solid/liquid interface and is difficult to form compounds. By affecting the solidification and thermal deformation behavior， it changes the microstructural characteristics and thus affects the final mechanical properties. This article summarizes the distribution characteristics of phosphorus during the solidification process and its impact on solute segregation and solidification microstructure， the influence of solidification microstructure changes on subsequent thermal deformation behavior， the phosphorus segregation behavior during heat treatment and aging processes and its effect on microstructure， the influence mechanism of phosphorus segregation characteristics and microstructure changes on mechanical properties and deformation mechanisms. The results show that P tends to become enriched at the solid/liquid interface front during solidification， thereby promoting element segregation. After heat treatment， P segregates at grain boundaries or phase interfaces， optimizing the morphology of grain boundary precipitates and enhancing grain boundary strength. The influence of P on the hot deformation behavior arises from the dual effects of solute drag by phosphorus atoms and the promotion of recrystallization nucleation by MC carbides. The influence of P on the hor deformation behavior is related to the state of alloy. The appropriate P content can improve the creep rupture strength of alloys； however， this beneficial effect is constrained by both the alloy system and the magnitude of creep stress. Based on the results mentioned above， this paper established the influence mechanism of P in the entire process of casting， forging， and component performance. It also briefly introduces the current problems and further research directions.关键词：Phosphorus;Nickel/nickel Iron-based Alloys;Solidification Behavior;Hot Deformation Behavior， Mechanical Properties13|1|0更新时间：2025-09-02
- 摘要：As one of the fourth-generation nuclear reactors， the Lead-cooled Fast Reactor （LFR） has garnered significant attention owing to the superior thermophysical and neutron properties of the Lead-Bismuth Eutectic （LBE）. However， the compatibility between its structural materials and liquid LBE remains a critical barrier to its advancement. Liquid Metal Embrittlement （LME）， one of the most prominent challenges， markedly diminishes the elongation and fatigue life of structural materials under specific conditions， thereby jeopardizing the safety and reliability of the reactors. This paper focuses on the LME issue in LFR structural materials， elucidating the LME behavior of key candidate structural materials-ferritic/martensitic steel， aluminum-containing ferritic steel， austenitic steel， and aluminum-containing austenitic steel in high-temperature liquid LBE， while clarifying their respective sensitivities to LME of various materials To address this formidable challenge of LME， the paper examines various influencing factors， including temperature， oxygen concentration， strain rate， pre-exposure， and metallurgical state， summarizing the current understanding of how these factors affect LME and their underlying mechanisms. Finally， based on existing research findings， the paper provides an outlook on the future prospects for enhancing the comprehension of the LME mechanism.关键词：Lead-cooled Fast Reactor;Lead-bismuth Eutectic;Liquid Metal Embrittlement;Structural Materials;Influencing Factors7|3|0更新时间：2025-09-02
- 摘要：This paper summarizes the development history and application performance research results of domestic and foreign scholars on anti-oxidation low expansion In783 alloy. The resistance of stress accelerated grain boundary oxidation （SAGBO） performance of the alloy has been greatly improved by β phase precipitation， which makes the alloy exhibit low thermal expansion coefficient （CTE）， good oxidation resistance and comprehensive mechanical performance below 750 ℃. It is widely used in the manufacturing of sealing components for aviation engines and bolts for ultra supercritical steam turbines. The research results of domestic scholars on the microstructure and properties of GH6783 alloy （Chinese grade GH6783） during domestication process are summarized. After long-term service， needle shaped Ni5Al3 phase precipitates inside the β phase， significantly deteriorating the plasticity of GH6783 alloy at 650 ℃. The anatomy analysis of the microstructure of currently imported In783 alloy rods reveals that the uniformity of the β phase microstructure was far worse than the results reported in the literature. It not only contains a large mass of primary β microstructure， but also has a suspected needle-like Ni5Al3 phase inside the β phase. Daye Special Steel Co.， Ltd. has conducted systematic research on the double vacuum smelting， electrode annealing， high-temperature homogenization and forging process of GH6783 alloy， and achieved significant results， with a significant improvement in the uniformity of microstructure and mechanical properties of GH6783 rod material. Regarding to serious anisotropy high tensile plasticity at 650°C of GH6783 alloys rods produced at home and abroad， it is found that this is related to the orientation of the γ' phase， and the relevant research work is being further conducted.Finally， the application prospects and future research directions of GH6783 alloy are discussed to meet the major national demands and the demand for advanced high-temperature alloy materials for sustainable social development.关键词：GH6783;In783;β - phase;Oxidation Resistant;Low Epansion Superalloy14|3|0更新时间：2025-09-02
Overview
- 摘要：Steam oxidation corrosion resistance is an important index to evaluate boiler steel. In this study 9Cr-3Co-2W martensitic heat-resistant steel （/% 0.08C， 0.40Si， 0.40Mn， 9.00Cr， 0.20Ni， 0.50Mo， 1.50 W. 0.05Nb， 0.20V， 0.07N， 0.030Al， 0.0012B， S≤0.010， P≤0.020）， the oxidation kinetics curves of the two groups without rare earth and with rare earth w［Ce］ 0.03% in 625 ℃ water vapor environment were carried out， and the morphology and structure of the oxide film were analyzed by SEM and XRD. The results show that the outer layer of iron oxide scale in both sets of experimental steel are mainly rich in Fe oxide Fe3O4 or Fe2O3， and the inner layer is rich in Cr and Fe oxides （Fe，Cr）2O3 and （Fe，Cr）3O4 in the 625 ℃ water vapor environment. However， the outer layer of iron oxide scale in the experimental steel without rare earth addition has poor density ， and even cracks appear. The experimental steel with rare earth added has dense outer oxide layer and large chromium-rich oxide layer thickness. On the surface of the oxidation kinetics curve， at the initial stage of oxidation （0 h-200 h）， with the extension of oxidation time， the oxidation rate of the test steel is large. After the oxidation time exceeds 200 h， the oxidation rate gradually decreases， and after 2 000 h， the oxidation rate approaches the level， and the oxidation rate continues to decline and gradually becomes stable. The addition of a small amount of rare earth Ce can help to form a dense oxide film and improve the oxidation resistance of the steel.关键词：Martensite Heat Resistant Steel;Rare Earth Elements;Oxidation Kinetics;Oxide Film;Oxidation Rate;Oxide282|15|0更新时间：2025-09-02
- 摘要：The production process of P92 heat-resistant steel continuous casting billets （
- 摘要：This article mainly introduces the process flow， process difficulties， and innovative points of hot-rolled direct production of large-diameter medium thick wall P22 seamless steel tubes with a diameter of over
- 摘要：Based on the standard composition of 316 L alloy， a type of Cr， Ni， and Nb strengthened austenitic stainless steel （denoted as 0.03C-XCr-14Ni-2.3Mo-0.35Nb-Fe steel） was designed. Analytical techniques such as optical microscopy （OM）， scanning electron microscopy （SEM）， transmission electron microscopy （TEM）， tensile testing， and impact testing were employed to investigate the microstructures and mechanical properties of hot-rolled plates with three Cr contents （16%， 18%， and 21%） in both solution-treated and aged states （aged at 400 ℃for 1 000 hours）. The results indicate that the main precipitated phases in the alloy are NbC and delta-ferrite. With increasing Cr content， the volume fraction of delta-ferrite significantly increases， while the quantity of NbC remains nearly unchanged. After thermal aging for 1 000 hours， the delta-ferrite phase remains stable， and no new phases are observed， with minor fluctuations in mechanical properties. As Cr content increases， the room-temperature and 350 ℃tensile yield strength and ultimate tensile strength of both solution-treated and aged alloys show slight upward trends. However， the elongation and impact energy exhibit minor variations from 16Cr to 18Cr but sharply decrease in the 21Cr alloy. The higher Cr content promotes the precipitation of delta-ferrite， leading to the formation of localized cleavage regions during fracture. This alters the fracture mode from ductile to brittle， resulting in a rapid decline in elongation and impact energy for the 21Cr alloy.关键词：Austenitic Stainless Steel;δ-ferrite;Thermal Aging;Cr Content;Mechanical Properties5|2|0更新时间：2025-09-02
-
Effect of C and Mo Content on Microstructure and Short-term Properties of IN617 Heat-resistant Alloy
摘要：To explore the optimal composition content of IN617 alloy for stable service under more severe conditions， different composition systems of the alloy were designed by changing the content of carbon and molybdenum， which are the main forming elements of carbides in the precipitation strengthening of the alloy. The effects of element content on the microstructure evolution and mechanical properties of IN617 alloy were systematically analyzed by scanning electron microscopy （SEM）， transmission electron microscopy （TEM）， electron probe microanalysis （EPMA）， differential thermal analysis （DSC）， thermodynamic calculation， tensile and impact tests.The results show that the secondary dendrite spacing can be significantly refined by appropriately increasing the content of C and Mo. When the content of C increases from 0.054% to 0.066%， the secondary dendrite spacing decreases from 13.6 μm to 8.3 μm. When the content of Mo increases from 8.53% to 9.51%， the secondary dendrite spacing decreases from 10.2 μm to 8.3 μm. At the same time， with the increase of element content， the volume fraction of primary precipitates in the as-cast alloy increases significantly. For every 0.01% increase in C， the volume fraction of carbides increases by about 1.0 %. Mo increases by 1.0%， and the volume fraction of carbides increases by about 0.45%.The precipitation mechanism is mainly Ti（C，N）-M6C-M23C6 three-phase symbiosis and M6C-M23C6 two-phase symbiosis， and the effect of element change on the mechanism is limited. Due to the decrease of dendritic segregation and the increase of carbides， the alloys with high C and Mo contents exhibit better mechanical properties. The tensile strength and yield strength of the low C high Mo alloy at room temperature are 762.5 MPa and 337.0 MPa， respectively. The impact absorbed energy is 463.5 J， and the tensile strength and yield strength at 800 ℃ are 419.5 MPa and 192.0 MPa， respectively. The tensile strength and yield strength of the alloy with high C and low Mo are 770.5 MPa and 323.5 MPa at room temperature， and 409.5 MPa and 192.5 MPa at 800 ℃. The tensile strength of the alloy with high C and high Mo at room temperature is 792.0 MPa， and the yield strength is 340.0 MPa. At 800 ℃， the tensile strength and yield strength of the alloy are 422.0 MPa and 210.0 MPa， respectively， which are higher than those of the other two alloys. However， the toughness of the alloy decreases slightly， and the impact absorbed energy is about 100.0 J lower than that of the alloy with low C content.关键词：IN617 Alloy;Dendritic Segregation;Microstructure;Mechanical Properties3|3|0更新时间：2025-09-02 - 摘要：The influence of Ti microalloying on the microstructure and mechanical properties of a novel Fe-Ni-based superalloy GH1059 with high-strength， high-toughness and long-life for fast reactors was investigated using SEM， EBSD， and TEM. The results showed that the addition of Ti significantly increased the amount of Ti-rich MC carbides， which precipitated in a finer and more dispersed manner， while effectively suppressing the formation of M23C6 carbides at grain boundaries （GBs）. With increasing Ti content， the average grain size of the alloy gradually decreased， while the fraction of low-Σ coincidence site lattice （CSL） boundaries remained largely unchanged. The results of 750 ℃ tensile and room temperature impact properties showed that Ti microalloying can simultaneously improve both strength and toughness. The tensile fracture mode was a mixed-mode fracture， and the deformed microstructure was mainly composed of dislocation cells and sub-grains. The improvement in mechanical properties were primarily attributed to solid-solution strengthening by Ti atoms， precipitation strengthening from TiC， grain refinement， and enhanced GB bonding force.关键词：Ti Microalloying;Fe-Ni-based Superalloy;Microstructure;Tensile Properties;Impact Toughness8|5|0更新时间：2025-09-02
Product Research and Development
- 摘要：Based on the principle of low eutectic point， a new basic slag system for electric slag remelting of FB2 heat-resistant steel was designed and calculated by FactSage software. The effects of traditional slag system 69.65% CaF2-29.85% Al2O3-0.5% B2O3 （1#） and new slag system 50.4% CaF2-26.5% CaO 19.6% Al2O3 3% MgO 0.5% B2O3 （2#） on the content changes of easily oxidizable elements in steel were compared and investigated using slag-metal equilibrium and 10 kg electroslag remelting experiments.The results show that ， compared with the traditional slag system， the melting temperature， viscosity and resistivity at different temperatures of the new design slag system are lower.When the activity of Al2O3 component in the slag is high and the activity of SiO2 and B2O3 components is at a low level， Si and B probably will react with low oxygen potential Al2O3 between the slag and the metal based on thermodynamic calculations. The content of w［B］ in the reaction equilibrium between the two slag systems and FB2 steel is 0.001 9% ，0.004 3%， respectively. In both slag series， Si and B elements will be burned and Al is increased in steel during slag-metal equilibrium and electroslag remelting smelting. In 2# slag series， the element fluctuation is small， and the variation range of element content decrease significantly after 60 min of slag-metal equilibrium time. In contrast， the change in element content in the electric slag ingot after remelting is smaller.关键词：FB2 Heat Resistant Steel;Electroslag Remelting;Slag System;Element Loss6|4|0更新时间：2025-09-02
- 摘要：Using optical microscope， scanning electron microscope and energy dispersive spectrometer， the casting microstructure of 12 tons of ingots of as-cast condition C650R nickel-based alloy used in the 650 ℃ultra-supercritical steam turbine rotor， smelted by the three-process method （VIM+PESR+VAR）， and the microstructure after different homogenization treatments were studied. The high-temperature thermoplasticity before and after homogenization treatment was also compared. The results show that in the self-consumption ingots of
Smelting and Solidification
- 摘要：In the process of rotary rolling and piercing for austenitic heat-resistant alloy， the improper selection of process parameters may result in phenomena such as coarse grain and mixed crystal in the pipe billet， or even fracture during processing， thereby impacting subsequent deformation and final product performance. Based on the previous thermaldeformation tests， this study established a material model for SP2215 alloy and utilized finite element software Simufact Forming 16.0 to simulate the rotary rolling and piercing of the alloy. The study analyzed dynamic changes in metal flow， strain field， stress field， strain rate field， temperature field， and rolling force during the skew rolling process. The simulation results are consistent with the actual deformation patterns. Furthermore， this study explored how process parameters such as head forward amount， roll speed， and initial temperature of billet affect both skew rolling performance and microstructure of the alloy. Ultimately an optimal rotary rolling and piercing process for the alloy is determined： head forward amount of 50 mm； roller spacing of 95.84 mm； guide plate spacing of 116.06 mm； roller speed at 50 r/min； and initial temperature range for tube billet at 1 100 ℃-1 150 ℃.关键词：SP2215 Heat Resistant Alloy;Rotary Rolling and Piercing;Simufact Forming;Finite Element Simulation1|1|0更新时间：2025-09-02
-
The Effect of Rare Earth on the Precipitated Phases During Aging Process of T91 Heat-resistant Steel
摘要：Martensitic heat-resistant steel with 9%-12%Cr represented by T91 is widely used in ultra-supercritical thermal power systems due to its excellent high-temperature performance. However， the creep performance degradation caused by phase precipitation and microstructure instability during long-term service is still the key bottleneck limiting its service life.This study systematically investigates the effects of rare earth （RE） w［Ce+Y］ addition （0%， 0.027%， and 0.064%） on the precipitation phases evolution of T91 steel during aging at 550 ℃. Combining with SEM/TEM characterization， the mechanism of RE Ce-Y composite addition in stabilizing microstructures are revealed. The results show that RE promotes the enrichment of Ce and V in the M23C6 phase around and inside， and restricts the coarsening of precipitated phases by hindering the diffusion of Cr in the matrix. During the 3 000 h aging process， the coarsening coefficient of M23C6 phase decreases by 52%， while Y does not appear to be significantly enriched. In addition， the number density of MX phase is increased by 32% through modified inclusions by RE， and remains unchanged after aging for 3 000 h by inhibiting dislocation recovery.This study confirms that rare earth microalloying is an effective strategy to improve the high-temperature microstructural stability of martensitic steels， and provides a theoretical basis for designing next-generation long-life， high-strength heat-resistant steel.关键词：Rare Earth;T91 Heat-resistant Steel;Precipitated Phase;Aging Process219|15|0更新时间：2025-09-02 - 摘要：Thermal compression deformation experiments on Ni-Cr-Fe heat-resistant alloy for advanced ultra-supercritical boilers were conducted using a Gleeble-3500 thermal simulator testing machine over a temperature range of 950 ℃–1 250 ℃， strain rates of 0.01 s⁻¹-10 s⁻¹， and a strain of 0.7. Based on the Arrhenius hyperbolic sine model， strain factor is innovatively introduced to construct an improved constitutive model suitable for heat-resistant alloys， and two indexes， correlation coefficient R and absolute error δ， are used to evaluate the accuracy of the model's prediction of rheological stress； At the same time， by constructing the hot processing map of the heat-resistant alloy and the microstructure analysis， the optimal range of hot working process parameters of the alloy is systematically evaluated and determined. The results showed that the optimal fitting order of the material constants and strain of the improved constitutive model with coupled strain was 6， the correlation coefficient R was 0.988 89， and the absolute error δ was 5.905%. The model had good predictive ability for the rheological stress of heat-resistant alloy； The activation energy Q for hot deformation was calculated as 389 kJ/mol. Based on microstructural analysis， the optimal hot working process for the Ni-Cr-Fe heat-resistant alloy was identified as 1 150 ℃-1 200 ℃ and 0.1 s⁻¹-1 s⁻¹.关键词：Advanced Ultra-Supercritical;Ni-Cr-Fe Heat-resistant Alloy;Constitutive Model;Hot Processing Map1|0|0更新时间：2025-09-02
- 摘要：9Cr martensitic heat-resistant steel is an important candidate material for ultra-supercritical steam turbine rotors. Due to the large size of the rotor forgings， there is a greater tendency for microstructure inheritance. The microstructure and mechanical properties of 9Cr martensitic heat-resistant steel at different austenitization temperatures and isothermal annealing times were studied using optical microscopy combined with tensile and impact tests. The results showed that the austenitization temperature had a significant effect on the isothermal transformation degree of 9Cr martensitic heat-resistant steel. The austenitization temperature of this heat-resistant steel before isothermal annealing should be controlled between 950 ℃-1 030 ℃； The coarse martensitic structure formed after forging can be transformed into a ferrite+pearlite-like structure by isothermal annealing at 720 ℃， effectively breaking the microstructure inheritance and laying a good organizational foundation for subsequent quenching and tempering treatment.The effect of insulation at 720 ℃ for 30 hours-100 hours on the grain size after subsequent quenching and tempering treatment showed a weak correlation. With the extension of holding time， atomic diffusion became more complete and the distribution of microstructure became more uniform. When annealing at 720 ℃ for 50 hours to 80 hours， the material exhibited excellent comprehensive performance.This study provides theoretical basis and engineering reference for the high-performance heat treatment process design of 9Cr martensitic heat-resistant steel forgings.关键词：9Cr Martensitic Heat-Resistant Steel;Austenitizing Temperature;Isothermal Transformation;Heat Treatment Process18|2|0更新时间：2025-09-02
- 摘要：05Cr17Ni4Cu4Nb steel is a martensitic precipitation-hardened stainless steel that frequently exhibits surface cracking during secondary forging， significantly compromising forging efficiency and product yield.In this study， the original austenite microstructure， martensite microstructure， phase composition and hardness of the secondary forging bar surface defect samples were tested. The results demonstrate that the observed surface cracking of secondary forging bar propagates along intergranular paths， with Cu embrittlement and mixed grain structure identified as primary contributing factors. Under high-temperature forging conditions， mixed grain structure and copper segregation exhibit a synergistic interaction. Abnormal growth of some prior austenitic grains within the mixed structure reduces the total grain boundary area， leading to increased Cu atom concentration per unit boundary area. Furthermore， inhomogeneous local strain rates during forging in mixed grain structures promote stress concentration at large/small grain ， accelerating Cu segregation to grain boundaries. At forging temperatures， locally enriched Cu atoms melt at grain boundaries， forming nanoscale liquid films. This liquid acts as a "lubricant，" significantly reducing grain boundary migration resistance and promoting rapid boundary movement， thereby facilitating abnormal grain growth and mixed structure formation. Besides Cu segregation， excessively high initial forging temperature also promotes mixed grains，excessively high initial forging temperature induces an oscillating "plunge-recovery" cycle in the billet surface temperature， causing dynamic thermal inhomogeneity. Significantly enhanced grain boundary mobility in localized high-temperature micro-regions allows preferential rapid growth of certain grains， forming mixed structures. This study mitigated copper segregation by reducing the electroslag remelting rate from 7.0-6.5 kg/min to 6.0-5.5 kg/min and suppressed mixed grain tendency by lowering the initial forging temperature from 1 180 ℃ to 1 160 ℃. The optimized forging process successfully eliminated surface cracking during secondary forging.关键词：Martensitic Precipitation-Hardened Stainless steel;Secondary Forging;Surface Cracking;Cu Embrittlement;Mixed Grain2|2|0更新时间：2025-09-02
- 摘要：The influence laws of solution treatments at diverse temperatures and the cooling modalities subsequent to solution treatments on the microstructure and properties of the alloy were investigated. The outcomes reveal that within the temperature range of 1 100 ℃ - 1 160 ℃， with the elevation of the solution treatment temperature， carbides dissolve back into the matrix， which makes the grain grow and has a certain adverse effect on the strength and plasticity of the alloy. More thorough dissolution of carbides can further facilitate the precipitation of more continuous M23C6 - type carbides along the grain boundaries during the ensuing aging treatment， consequently reducing the mechanical properties of the alloy. Taking into account the microstructure characteristics， 1 140 ℃ can be chosen as the solution treatment temperature for this alloy.A relatively sluggish cooling approach subsequent to the alloy's solution treatment augments the precipitation propensity of M6C type carbides and the size of these carbides. Additionally， it can prompt the precipitation of the γ′ phase， thereby enhancing the strength of the alloy. In the event that the alloy undergoes air - cooling subsequent to solution treatment， a substantial quantity of fine granular carbides will precipitate at the sites of the original carbides and their adjacent regions during the aging treatment. Abundant γ′ phases precipitate both during the slow - cooling process following solution treatment and during the aging treatment， remarkably elevating the strength of the alloy. Simultaneously， the precipitation of a large number of carbides at the grain boundaries attenuates the strength of the grain boundaries， imposing an adverse influence on the plasticity and impact energy of the alloy.关键词：Nickel-based Alloy;Solution Heat Treatment;Cooling Rate;Microstructure;Mechanical Property3|1|0更新时间：2025-09-02
Forming and Phase Transition
- 摘要：The effects of two-stage aging time at 720 ℃ and 620 ℃ on the η phase and γ'/γ'' phase of GH4706 superalloy were studied using optical microscopy， scanning electron microscopy， etc. The room temperature strength， impact， and creep rupture life of the material were tested under different aging times. The results showed that the room temperature strength changed little at 720 ℃ and 620 ℃ two-stage aging with increasing aging time， the room temperature impact performance decreased， and the creep rupture fracture time gradually increased； Meanwhile， the quantity and size of the η phase gradually increased with the increase of aging time， and the shape of the η phase gradually changed from strip to block， while the morphology of the γ ´/γ´´ phase changed relatively little， and the γ´/γ´´ phase coarsened with the increase of aging time； By analyzing the evolution laws of γ '/γ'' phases and η phases of alloy under different aging time conditions， it was revealed that appropriate coarsening of γ´/γ´´ phases can improve the room temperature strength and high temperature durability under different aging time conditions， while the coarsening of η phases can significantly reduce the room temperature impact performance and strength of matrix， but can obviously improve the high temperature durability.关键词：GH4706 Superalloy;Aging Time;Precipitation;Mechanical Properties2|2|0更新时间：2025-09-02
- 摘要：In order to solve the problem of unstable cross-sectional shrinkage of 1Cr16Ni2MoN steel， OIM， SEM， TEM， and thermodynamic calculations and other means were used to study the microstructure and ductility of 1Cr16Ni2MoN martensitic heat-resistant steel for gas turbine blades under different tempering processes. The results show that 1Cr16Ni2MoN steel quenched at 1 040 ℃ and 550 ℃-560 ℃， with a tensile strength of over 1 200 MPa， a yield strength of over 1 000 MPa， and a cross-sectional shrinkage rate of over 65%； The main type of carbide precipitation is M23C6， which forms a banded structure composed of large carbide particles due to Cr segregation in the microstructure， accompanied by the formation of δ-ferrite. With the increase of tempering temperature， the amount of carbide precipitation increases， and the carbide at grain boundary and Flat noodles boundary gathers and coarsens， which leads to the decrease of the bonding force between flat noodles and phase interface， which can accelerate the generation and propagation of cracks， thus reducing the reduction of area and impact toughness.Taking into account the control of δ - ferrite and cross-sectional shrinkage rate， it is necessary to adjust the composition， the content of C should be minimized as much as possible， with the carbon content maintained at 0.15%， the content of N should be suitably increased to upper limit of 0.007%， and the diffusion annealing process should be implemented to reduce the enrichment of carbides resulting from segregation.关键词：Section Shrinkage;Martensitic Heat-resistant Steel;1Cr16Ni2MoN;M23C6;Blade1|1|0更新时间：2025-09-02
- 摘要：The addition of trace rare earth elements can significantly enhance the oxidation resistance of alloys， but the action mechanisms of different rare earth elements vary and have not been widely understood. In this paper， a differential thermal analyzer was used to carry out continuous heating oxidation， isothermal oxidation， and cyclic oxidation tests on heat-resistant steel. The results showed that the addition both rare earth elements w［Ce］0.056% and w［Y］0.048% can significantly improve the high-temperature oxidation resistance of heat-resistant steel. Combined with the results of analytical methods such as X-ray diffraction， scanning electron microscopy， and energy-dispersive spectroscopy， it was found that： in the outer oxidation layer， the heat-resistant steel containing rare earth elements formed a dense Cr₂O₃ layer and FeCr₂O₄ spinel outer oxide layer； In the inner oxidation layer， the main component was SiO₂， while Y₂O₃ coexisted in the inner oxidation layer of heat-resistant steel containing rare earth Y. Therefore， the influence mechanisms of rare earth Ce and Y on the high-temperature oxidation resistance of austenitic heat-resistant steel are as follows： rare earth elements Ce and Y can both promote the diffusion of chromium elements to the oxidation layer to form a dense Cr₂O₃ layer； rare earth Y generates Y₂O₃ in the inner oxidation layer， which jointly exerts a pinning effect with SiO₂.关键词：Austenitic Heat-resistant Steel;Rare Earth Elements Ce and Y;High-temperature Oxidation Resistance;Pinning Effect292|16|0更新时间：2025-09-02
- 摘要：This study investigates the effects of yttrium oxide （Y2O3） content on the tribological and corrosion resistance properties of the chromium infiltration layer in 316H heat-resistant steel through the solid powder pack cementation method. The results indicated that rare earth （Y2O3） doping significantly regulated the formation process of the infiltration layer. When the w［Y2O3］ was 4%， the thickness of the infiltration layer reached a maximum value of 143.78 μm， which was 10.2% higher than that of the undoped group. The rare earth Y2O3 promoted the preferential growth of the Cr₂C phase. When the w［Y2O3］ was 2%， the surface micro-Vickers hardness （HV） was enhanced to 656HV， the friction coefficient was reduced by 52.7% （to 0.355）， and the wear rate was decreased by 74.5%. The properties of the infiltration layer were optimized by rare earth through accelerating chromium diffusion， refining grains， and regulating phase composition. However， there was a concentration threshold for its effect： excessive w［Y2O3］ （>4%） not only consumed a large amount of catalyst， reduced the diffusion driving force of active chromium atoms， but also increased the surface roughness （Ra=235.4 nm） and deteriorated the tribological properties. Additionally， the chromium-depleted phenomenon at the grain boundaries caused by Y2O3 addition had a negative impact on corrosion resistance. This research provides a theoretical basis for optimizing the rare earth modified chromium infiltration process ， which is of great significance for developing surface strengthening technologies with high wear resistance and low friction.关键词：Rare Earth Doping;Chromium Infiltration Process;Wear Resistance;Corrosion Resistance177|3|0更新时间：2025-09-02
Application and Service
- Technical support is provided by Beijing Founder electronics co., LTD 鄂ICP备2022000839号
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
- Total Visits：35684
0