搜索到468篇“ 显微组织演变“的相关文章
690合金显微组织演变对其导热性能的影响
2025年
根据焦耳炉电极材料使用工况,开展了690合金电极组织演变对其导热性能的影响。使用纯金属冶炼了典型成分的690合金,并通过锻造、热轧、冷轧获得不同状态的690样品。通过SEM、EBSD、XRD和闪光法测量导热系数等手段,测试了不同状态690样品的晶粒尺寸、晶界类型、晶界分布、位错密度、析出相种类,明确了焦耳炉电极用690合金材料在不同加工状态下的显微组织演变及其对导热性能的影响规律。结果表明:热轧态690合金的热导率最高,锻态次之,而冷轧态690合金的热导率最低。其原因为:(1)不同变形工艺下的690合金晶粒尺寸和晶界总面积有显著变化,冷轧态合金具有最小的晶粒尺寸和最高的晶界总面积;(2)锻态、冷轧态690合金晶界以小角度晶界为主,690合金低ΣCSL晶界均以Σ3晶界为主;(3)冷轧态690合金具有最高的位错密度;(4)冷轧态690合金热导率大幅下降的主要原因在于高的晶界总面积比例和冷轧后的高位错密度。
丰涵朱永昌宋志刚顾洋刘哲杨德博
关键词:690合金显微组织热导率
固溶温度对Haynes230合金热轧棒材显微组织演变和拉伸性能的影响
2025年
Haynes230合金是超高温气冷堆、光热发电和先进超超临界燃煤发电机组高温部件的重要候选材料。为了建立合金显微组织控制准则,采用热轧成形板材,通过调整固溶温度,研究了固溶处理过程中析出相溶解行为和晶粒尺寸变化等显微组织演变规律,研究结果显示,热轧态板材具有奥氏体等轴晶组织,晶粒分布均匀,平均晶粒尺寸约为32μm,主要析出相为富W和Mo的M6C碳化物;在950~1150℃,M6C碳化物含量和颗粒尺寸未发生明显变化,晶粒尺寸变化缓慢;随着固溶温度增高到1180~1200℃,M6C碳化物含量有所降低,颗粒尺寸减小,晶粒发生粗化;当固溶温度升高到1230、1250℃时,碳化物含量和尺寸明显减小,平均晶粒尺寸增至142、201μm;随着固溶温度增高,室温和750℃拉伸强度趋于降低,900℃抗拉强度升高;基于试验研究,提出Haynes230合金热轧板材晶粒尺寸控制在76~142μm,相应的固溶温度选用1200~1230℃。
丁佐军郭亮徐晓懿魏航
关键词:固溶处理晶粒尺寸碳化物
稀土Ce对Fe-Ni-Al马氏体时效钢等温过程显微组织演变的影响
2025年
通过OM、XRD、SEM、TEM等手段系统研究了马氏体时效钢在时效过程中显微组织演变规律及其力学性能,并与添加稀土Ce的马氏体时效钢进行了对比分析。结果表明,两种试验钢的硬度随着时效时间延长呈先上升,后进入宽的硬度平台趋势。加入稀土Ce后,试验钢内部板条马氏体束变得更加细小,板条分布更加弥散均匀,试验钢的硬度略微降低,在500℃时效3 h后,掺加稀土Ce的试验钢的延伸率有所增加,但强度变化不大,抗拉强度达到2 053 MPa。试验钢在时效过程中,内部析出两种类型的析出物,一种为较大尺寸的NbC析出颗粒,另一种为小尺寸的弥散分布的NiAl相。加入稀土Ce后,NbC析出相尺寸变小,NiAl相的析出变缓。利用HRTEM表征后发现,B2-NiAl析出相与基体共格,同时得到了B2相和基体的晶格常数,二者的错配度为0.2%。
谭会杰王海燕华连庚高雪云吕萌于大威邢磊
关键词:马氏体时效钢显微组织析出相
Microstructure evolution of K439B Ni-based superalloy casting with varying cross-sections by experiments and simulations
2025年
Casting experiments and macro-micro numerical simulations were conducted to examine the microstructure characteristics of K439B nickel-based superalloy casting with varying cross-sections during the gravity investment casting process.Firstly,microstructure analysis was conducted on the casting using scanning electron microscopy(SEM)and electron backscatter diffraction(EBSD).Subsequently,calculation of the phase diagram and differential scanning calorimetry(DSC)tests were conducted to determine the macro-micro simulation parameters of the K439B alloy,and the cellular automaton finite element(CAFE)method was employed to develop macro-micro modeling of K439B nickel-based superalloy casting with varying cross-sections.The experimental results revealed that the ratio of the average grain area increased from the edge to the center of the sections as the ratio of the cross-sectional area increased.The simulation results indicated that the average grain area increased from 0.885 to 0.956 mm^(2)as the ratio of the cross-sections increased from 6꞉1 to 12꞉1.The experiment and simulation results showed that the grain size became more heterogeneous and the grain shape became more irregular with an increase in the ratio of the cross-sectional area of the casting.CAFE modeling was an effective method to simulate the microstructure evolution of the K439B alloy and ensure the accuracy of the simulation.
Da-shan SUIDe-peng ZHOUYang LIUYu SHANAn-ping DONG
Microstructure evolution of 7050 aluminum forgings during surface cumulative plastic deformation
2025年
To elucidate the mechanisms of regulating the microstructure uniformity in 7050 aluminum forgings through surface cumulative plastic deformation(SCPD),the microstructure under different solution treatments was investigated using metallographic observation(OM),electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),and X-ray diffraction(XRD).The findings demonstrate that the most uniform microstructure in the forgings is achieved with a solution treatment at 470℃for 30 min.The SCPD process generates a significant number of needle-shaped precipitates,resulting in a higher dislocation density and stored energy.Solution treatments alleviate the pinning effect of second-phase particles and facilitate static recrystallization(SRX)in forgings,leading to a reduction in grain size.Additionally,mechanical testing results demonstrate 7%−13%increase in tensile strength and more uniform elongation of the forgings in different directions.
Jian-liang HUZe-xiong ZHANGCheng XINGXiu-jiang WUShi-quan HUANGHong BO
High-temperature fatigue cracking mechanism and microstructure evolution of aero-engine K4169 superalloy in service process
2025年
By using fatigue crack propagation testing and microstructural characterization,the crack fracture and propagation mechanisms of K4169 superalloy under various loads were investigated.The results demonstrate that the grain sizes of K4169 superalloy significantly increase,and the precipitation of the needle-likeδphase and the Laves phase is observed.Voids and microcracks form at location of Laves phase enrichment,creating conditions for crack propagation.By the a−N(a is the crack length,and N is the number of cycles)relationship curve,the change in the fatigue crack growth rate with the increasing number of cycles progresses through three separate stages.The fracture process of K4169 superalloy under low-stress cyclic loading(3 kN)exhibits the ductile fracture.Subsequently,the fracture process starts to change from the ductile fracture to the brittle fracture as the stress increases to 4.5 kN.In the microstructures of fractures in both stress states,intergranular propagation is the mechanism responsible for crack propagation.Moreover,the Laves phase exists near the fracture crack,which is in line with the post-service structural phenomenon.
Song-jun WANGJian-jun HEZhi-hui GONGWei-ping LIJun-gang YANGYa-jun SHAOYu-hui CAIYue-xin DUCheng-wei YANG
关键词:MICROSTRUCTUREAERO-ENGINE
Prediction of microstructure evolution of ZK61 alloy during hot spinning by internal state variable model
2025年
An internal state variable(ISV)model was established according to the experimental results of hot plane strain compression(PSC)to predict the microstructure evolution during hot spinning of ZK61 alloy.The effects of the internal variables were considered in this ISV model,and the parameters were optimized by genetic algorithm.After validation,the ISV model was used to simulate the evolution of grain size(GS)and dynamic recrystallization(DRX)fraction during hot spinning via Abaqus and its subroutine Vumat.By comparing the simulated results with the experimental results,the application of the ISV model was proven to be reliable.Meanwhile,the strength of the thin-walled spun ZK61 tube increased from 303 to 334 MPa due to grain refinement by DRX and texture strengthening.Besides,some ultrafine grains(0.5μm)that played an important role in mechanical properties were formed due to the proliferation,movement,and entanglement of dislocations during the spinning process.
Jin-qi PANWen-cong ZHANGJian-lei YANGSong-hui WANGYong WUHuan LI
Microstructure evolution and mechanical properties of Mg−Gd−Zn alloy with and without LPSO phase processed by multi-directional forging
2025年
The homogenized Mg−5.6Gd−0.8Zn(wt.%)alloys were treated with water cooling and furnace cooling to obtain specimens without and with the 14H long-period stacking ordered(LPSO)phase.Subsequently,multi-directional forging(MDF)experiments were carried out.The microstructure and mechanical properties of different regions(the center,middle and edge regions)in the MDFed alloys were systematically investigated,and the effect of LPSO phase on them was discussed.The results show that the alloys in different regions undergo significant grain refinement during the MDF process.Inhomogeneous microstructures with different degrees of dynamic recrystallization(DRX)are formed,resulting in microhardness heterogeneity.The alloy with the LPSO phase has higher microstructure homogeneity,a higher degree of recrystallization,and better comprehensive mechanical properties than the alloy without the LPSO phase.The furnace-cooled alloy after 18 passes of MDF has the best comprehensive mechanical properties,with an ultimate compressive strength of 488 MPa,yield strength of 258 MPa,and fracture strain of 21.2%.DRX behavior is closely related to the LPSO phase and deformation temperature.The kinked LPSO phase can act as a potential nucleation site for DRX grains,while the fragmented LPSO phase promotes DRX nucleation through the particle-stimulated nucleation mechanism.
Jing-yi HUANGYao-ling LIUYu-xiang HANYing-chun WANChu-ming LIUZhi-yong CHEN
一种基于扩散模型的材料显微组织演变模拟方法
本发明涉及材料显微组织模拟技术领域,公开了一种基于扩散模型的材料显微组织演变模拟方法,包括以下步骤:获取显微组织原始图片;对显微组织原始图片进行预处理得到显微组织图片;基于材料显微组织演变模拟选择模型训练算法,对模型进行...
张聪张瑞杰尹海清
Q690碳钢焊接热影响区显微组织演变研究
2024年
本文研究了Q690碳钢在不预热条件下,采用Ar+CO2混合气体保护焊方法焊接时,焊接热输入对热影响区显微组织演变的影响。通过光学显微镜和扫描电子显微镜观察了焊接接头横截面的显微组织,并进行了显微硬度测试和冲击韧性测试。结果表明,随着焊接热输入的增加,热影响区的显微组织发生了显著变化,导致冲击韧性逐渐降低。通过控制焊接热输入量和优化焊接工艺参数,可以改善热影响区的组织性能并提高焊接接头的力学性能。
邢炜
关键词:焊接热影响区显微组织演变

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熊柏青
作品数:403被引量:1,433H指数:21
供职机构:北京有色金属研究总院
研究主题:显微组织 铝合金 力学性能 固溶处理 均匀化热处理
张永安
作品数:317被引量:1,302H指数:20
供职机构:北京有色金属研究总院
研究主题:显微组织 铝合金 力学性能 AL AL-ZN-MG-CU合金
宗亚平
作品数:54被引量:132H指数:8
供职机构:东北大学
研究主题:铁基复合材料 相场法 力学性能 相场法模拟 复合材料
张辉
作品数:724被引量:2,091H指数:24
供职机构:湖南大学
研究主题:机器人 机器视觉 铝合金 流变应力 热压缩变形
肖国庆
作品数:170被引量:432H指数:11
供职机构:西安建筑科技大学材料科学与工程学院
研究主题:自蔓延高温合成 复合粉 镁铝尖晶石 燃烧合成 铝酸钙