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利用材料相图与性能模拟计算软件JMatPro,研究了难熔元素W,Mo,Nb和Fe含量的变化对一种新型镍铁基高温合金拓扑密排相(TCP)和碳化物相析出及高温性能的影响。结果表明:新型镍铁基高温合金晶内强化相为γ′相,晶界为M23C6碳化物;在合金中添加Mo,W,Nb均可提高合金的持久强度和屈服强度;增加合金中Mo,Nb,Fe的含量会提高Laves相和σ相的析出温度;为避免在长期服役过程中合金析出较多的TCP相,在合金中添加不超过0.6%(质量分数,下同)的Nb或不超过1%的Mo和W,以使TCP相的析出温度尽可能低于使役温度。 相似文献
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镍基单晶高温合金因优异的高温力学性能而被广泛应用于航空发动机和地面燃气轮机的涡轮叶片等关键热端部件。Ru元素作为第四代、第五代镍基单晶高温合金的主要特征元素,其添加对合金从凝固特性到最终的服役性能都起到关键的影响。本文从镍基单晶高温合金的凝固特性、凝固组织、TCP相析出及蠕变性能等方面出发,综述了Ru元素对镍基单晶高温合金影响的研究进展,系统分析了Ru的添加对合金凝固路径、凝固特征温度、微观偏析等凝固特性及共晶、碳化物等凝固组织的影响规律,并重点探究了Ru的添加能抑制TCP相析出及提高合金蠕变性能的原因。目前由于多组元交互作用对组织与性能影响机理的复杂性,使得含Ru高温合金的成分设计与优化具有更高的挑战,建议未来含Ru高温合金的相关研究从富Ru新相的析出原因及抑制、Ru添加对凝固缺陷的影响及Ru与其他元素交互作用对“逆分配”效应及TCP相析出的影响机制等方面做进一步探究,为发展新型高性能含Ru高温合金的设计提供思路。 相似文献
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采用晶界萃取碳复型技术研究了不同强化程度的铁基、镍基高温合金晶界析出相随成分和晶粒度的变化规律及其对中高温塑性的影响。结果表明:合金的中高温拉伸塑性的高低主要取决于晶界析出相的种类、形貌、密度和分布等因素;随晶粒长大合金中高温塑性降低的主要原因是晶界相的析出量增多、分布密度增大而使之脆化所致。单纯晶粒几何尺寸的变化对拉伸塑性影响不明显。 相似文献
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采用晶界萃取碳复型技术研究了不同强化强度的铁基,镍基高温合金晶界析出相随成分和晶粒度的变化规律及其对中高温塑性的影响,结果表明,合金的中高温拉伸塑性的高低主要取决于晶界析出相的种,形貌,密度和分布等因素,随晶粒长大合金中高温塑性降低的主要原因是晶界相的析出量增多、分布密度增大而使之脆化所致,单纯晶粒几何尺寸的变化对拉伸塑性影响不明显。 相似文献
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超超临界锅炉过热器管材的高温组织稳定性及其改进研究 总被引:2,自引:1,他引:1
采用高温长期时效的方法研究了一种在700℃/375bar蒸气参数条件下作为过热器管材使用的镍基高温合金的组织稳定性,得出合金的组织不稳定性主要体现在γ′的粗化、り相的形成和晶界G相的析出.进而采用Thermo-Calc理论计算和分析,提出了通过调整Al、Ti和Si含量来改善组织稳定性的方法. 相似文献
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The high-temperature deformation behaviors of a typical Ni-based superalloy are investigated by hot compression tests under the strain rate of 0.001–1 s−1and temperature of 920–1040 °C. The experimental results show that the deformation behaviors of the studied superalloy are significantly affected by the deformation temperature, strain rate and strain. The flow stress increases with the increase of strain rate or the decrease of deformation temperature. The flow stress firstly increases with the strain to a peak value, showing the obvious work hardening behaviors. Then, the stress decreases with the further straining, indicating the dynamic flow softening behaviors. Considering the coupled effects of deformation temperature, strain rate and strain on the hot deformation behaviors of the studied Ni-based superalloy, the phenomenological constitutive models are established to describe the work hardening-dynamic recovery and dynamic softening behaviors. In the established models, the material constants are expressed as functions of the Zener–Hollomon parameter. The established constitutive models can give good correlations with the experimental results, which confirm an accurate and precise estimation of the flow stress for the studied Ni-based superalloy. 相似文献
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The understanding of temperature and time-dependent metal borides precipitation/dissolution is cru-cial for the design of the transient liquid phase(TLP)bonding process of Ni-based alloys.It however remains elusive despite substantial research efforts for many years mainly owing to the uncertainty on the precipitated metal borides and the complex thermo-kinetics in the process.In this paper,we have unambiguously constructed the micro/nanoscale map of the precipitated metal borides in the TLP bonded Ni-based Inconel 718 superalloy via a high-throughput transmission electron microscopy(TEM)analy-sis.Five types of metal borides were found to precipitate in the diffusion affected zone(DAZ)when the isothermal solidification is completed.They are the M5B3 with stacking faults,Ti-rich M3B4,and Nb-rich M3B4 at the grain boundaries as well as single-crystalline M5B3 and M3B2 inside the grains.Notably,the crystal structure of the faulted M5B3 was rationalized by a hybrid modelling approach integrating first-principles calculation and TEM experiments.The sublattice model,with the optimized thermodynamic model parameters,was used to reproduce the metal borides precipitation map in the TLP process using DICTRA software.Coupling with multiscale simulation and experimental data,the present work built a modified thermo-kinetic model,which enables the design of the TLP bonding process of Ni-based alloys that often involves complicated time-temperature schedules and the precipitation/dissolution of a vari-ety of different phases.The strategy can be applied to the design of the brazing process of other alloys or hvbrid materials such as ceramics and metal. 相似文献
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高温镍基单晶合金NiCoCrAlYTa涂层的抗热腐蚀性能 总被引:1,自引:0,他引:1
以往,对高温镍基单晶合金上采用低压等离子喷涂制备的NiCoCrAlYTa涂层的热腐蚀性能研究较少.为此,采用低压等离子方法在镍基高温单晶合金上制备了NiCoCrAlYTa涂层,采用涂盐法研究了Na2SO4对试样在1 123 K空气中热腐蚀的影响,同时分析了NiCoCrAlYTa涂层的形貌及结构.结果表明:高温镍基单晶合金遭受了严重的热腐蚀,出现了内硫化和内氧化;NiCoCrAlYTa涂层由于表面生成了致密、保护性的Al2O3膜,以及涂层中Cr和Ta元素的作用而表现出优异的抗热腐蚀性能.结果证实,NiCoCrAlYTa涂层可以很好地提高单晶合金的抗热腐蚀性能. 相似文献
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A. Toshimitsu Yokobori Jr. Tomoharu Uesugi Takeo Yokobori Akio Fuji Masaki Kitagawa Isamu Yamaya Masaaki Tabuchi K―oichi Yagi 《Journal of Materials Science》1998,33(6):1555-1562
Since the high-strength Ni-based superalloy, cast IN-100, is considered to be brittle at high temperatures, the stable creep crack growth region is limited. Therefore, technically, it is very difficult to perform creep tests and there are few experimental results on the creep crack growth behaviour of this material. We performed creep crack growth tests using Ni-based superalloy, cast IN-100, and derived the Q* parameter for this material, which characterizes the creep crack growth rate. Using this Q* parameter, we derived a law for the creep rupture life of this material. 相似文献
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《Materials Characterization》2007,58(10):941-946
The hot deformation characteristics of a Ni-based superalloy were studied in the temperature range 1050–1180 °C and strain rate range 0.01–10 s− 1 using hot compression tests. Processing maps for hot working were developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate, interpreted using a dynamic materials model. A hot deformation equation is given to characterize the dependence of peak stress on the temperature and strain rate. A hot deformation apparent activation energy of the Ni-based superalloy is about 496 kJ/mol. The processing maps of the Ni-based superalloy obtained in a strain range of 0.1–0.7 are essentially similar, which indicates that strain does not have a significant influence. The maps exhibit a clear domain with its peak efficiency at about 1140 °C and 0.01 s− 1; the domain has its peak efficiency of about 36–41% for different strains. On the basis of hot deformation microstructural observations, the full recrystallization region can be identified in the processing map at a strain of 0.7. 相似文献
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采用籽晶法制备含有大角度晶界(约20°)的双晶试板,通过分析不同Hf含量(质量分数:0%,0.4%)的含Re合金晶界处析出相、γ/γ′组织、晶界成分及1100℃/100MPa横向持久性能,研究Hf对晶界组织及高温力学性能的影响。结果表明:Hf显著提高了铸态合金大角度晶界处共晶和碳化物体积分数;热处理后,Hf显著抑制了晶界胞状再结晶组织的形成,含Hf合金的1100℃/100MPa横向持久寿命均显著提高。晶界持久性能与晶界析出相种类、形貌、含量和成分密切相关,而Hf元素在晶界未发现显著的偏聚。本研究对先进镍基单晶合金中晶界缺陷的评价及Hf元素晶界强化作用机制的认识具有一定的指导意义。 相似文献
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Fei Wang Junyan Liu Oliullah Mohummad Yang Wang 《International Journal of Thermophysics》2018,39(6):71
In this paper, thermal-wave radar imaging (TWRI) is introduced to detect debonding defects in SiC-coated Ni-based superalloy plates. Linear frequency modulation signal (chirp) is used as the excitation signal which has a large time–bandwidth product. Artificial debonding defects in SiC coating are excited by the laser beam with the light intensity modulated by a chirp signal. Cross-correlation algorithm and chirp lock-in algorithm are introduced to extract the thermal-wave signal characteristic. The comparative experiment between TWRI reflection mode and transmission mode was carried out. Experiments are conducted to investigate the influence of laser power density, chirp period, and excitation frequency. Experimental results illustrate that chirp lock-in phase has a better detection capability than other characteristic parameters. TWRI can effectively detect simulated debonding defects of SiC-coated Ni-based superalloy plates. 相似文献