滴定法测定镍基合金中铁量的不确定度评定

对三氯化钛-重铬酸钾滴定法测定镍基合金中铁量的不确定度产生原因进行了分析,对测量过程中的主要不确定度分量进行了评定,包括重铬酸钾标准溶液浓度带来的不确定度,滴定试样体积和滴定空白体积带来的不确定度,称重带来的不确定度和试验总重复性带来的不确定度。估算了各分量的大小,分析对结果影响相对大的分量为方法确认时的重复性以及滴定时重铬酸钾消耗体积的不确定度分量。     

铸造镍基合金热处理工艺对组织与性能的影响

本文采用了金相显微镜、Ｘ－射线衍射、电子探针和透射电子显微镜相结合的方法，研究了热处理工艺对铸造镍基合金组织的形态、成分、结构及机械性能与切削加工性能的影响。研究结果表明，该合金在９５０～１１５０℃范围内，有Ｐ相、μ相、Ｍ６Ｃ及少量σ相析出，经１２５０℃×１ｈ固溶处理后，具有最佳的综合机械性能和满意的切削加工性能。     

镍基合金渗铝机理的探讨

以Ni基合金为例，探讨了金属渗铝的形成机制，认为渗铝过程由四个步骤组成，主要受固态扩散控制，影响扩散速度的决定因素是渗铝温度，其次是渗铝时间，另外，渗铝温度的变化对不同活化能的相生成速度也不同。     

铌对新型Ni-Cr-Fe镍基合金力学性能的影响

新型Ni-Cr-Fe镍基合金(%:0.036～0.044C、16.71～17.10Cr、63.04～63.95 Ni、8.98～10.76Fe、2.50～2.88Mo、2.01～4.97Nb、0.06V、0.74～0.82Al、2.00～2.06 Ti)由25 kg真空感应炉熔炼,锻成Φ15 mm和14mm×14 mm棒材。采用扫描电镜(SEM),X射线衍射仪(XRD),化学相分析和拉力试验研究了铌含量对65Ni18Cr-10Fe合金组织和性能的影响。结果发现,随着合金中铌含量的增加,γ′、γ″、η相的析出数量增多,尺寸增大,形态由断续的颗粒、短棒状改变为长片层状;导致合金的室温强度随之升高,而塑性随之下降。     

镍基合金管加工破裂分析研究

镍基合金管加工破裂分析研究王志英（北京有色金属研究总院１０００８８）Ｎｉ－Ｍｏ－Ｃｒ－Ｆｅ－Ｗ合金是一种具有特殊性能和用途的合金，产品成本昂贵，提高成品率是非常重要的，但在研制中常出现旋裂现象，从而影响产品的质量和成品率。查明旋裂的原因是改进工艺，提...     

稀土化合物对粉末冶金镍基合金摩擦磨损性能的影响

用粉末冶金热压方法制备了几种含不同稀土化合物（LaF3,CeO2,La2O3)的Ni基合金，将合金制备为块样，45^#钢为环样，在环－块摩擦试验机上考察了稀土化合物含量及其种类对Ni基合金摩擦磨损性能的影响，研究结果表明：添加稀土化合物可明显改善合金在高载高速下的耐磨性能，这与其摩擦表面形成摩擦保护性“釉质层”密切相关。     

钛含量对Inconel 690镍基合金力学性能的影响

研究了Ti含量(0.35%～1.10%)对Inconel 690镍基合金(%:0.034～0.036C、29.40～29.68Cr、9.11～9.22Fe、0.34～0.36A1、0.004 4～0.004 5N)950～1 100℃水冷+715℃15～100 h空冷后的室温和350℃的组织和力学性能。结果表明,含1.10%Ti合金的强度(Rm和Rp0.2)较含0.35%～0.70%Ti合金的强度高200～400 MPa,强度提高的主要原因为715℃时效后1.10%Ti合金析出3.70%～3.99%γ′强化相,而0.35%～0.70%Ti合金715℃时效后γ′强化相析出量仅为0～0.53%。     

Advances in nickel-based cast superalloys

Nickel-based superalloys have served as the most competitive high temperature structural materials under highly stressed and aggressive operating conditions in a variety of applications for more than 60 years. The most demanding among all the applications has been the gas turbine aerofoil castings of modern aero-engines. These turbine parts operate in extremely aggressive environment of high velocity hot combustion gas-air mixture carrying highly corrosive ingredients at high pressure. Gas turbine aerofoil materials should therefore possess adequate resistance to creep, fatigue and aggressive environment. Materials design for such application therefore has been extremely challenging, particularly since the engine designers always aim at higher turbine entry temperature (TET) in order to achieve greater engine thrust and better fuel efficiency. In spite of enormous efforts made in the recent past towards developing ceramics and their composites, Ni-based superalloys continue to be most reliable blade and vane materials offering always the highest TET. This has been possible through better alloy design, improved blade cooling schemes, protective coatings and directional solidification (DS) of either columnar grains or single crystals (SC) along the most favorable 〈001〉 texture. During the last six decades, TET has gone up by about 500K. This article covers recent advances in cast Ni-based superalloys, including our own efforts in this direction. Extensive research at DMRL has led to the development of new generation Ni-based superalloys, designated as DMD-4 and DMS-4 for DS and SC processing, respectively. Simultaneously, expertise has been developed to cast DS and SC components for aero-engines. Technology has also been established for pilot scale production of these components.     

High refractory, low misfit ru-containing single-crystal superalloys

Single-crystal Ru-containing nickel-base superalloys with spherical γ′ precipitates have been observed in alloys with substantial amounts of Re and W and high levels of Ru. The γ′ precipitates did not experience stress-induced shape changes (rafting) during creep deformation at 950 °C and 290 MPa, indicative of a γ-γ′ lattice misfit very near zero. Furthermore, interfacial dislocation networks were not formed during creep deformation in the low misfit alloys. The alloys containing spherical precipitates had lower creep strengths than the alloys containing cuboidal precipitates at 950 °C and 290 MPa. Element partitioning between the phases was investigated in order to determine the origin of the unusual microstructural features. Transmission electron microscopy (TEM)-based energy-dispersive spectroscopy (EDS) analysis of the γ and γ′ phases indicates that Ru affects the partitioning of Re, which partitions much less strongly to the matrix than previously observed in Re-containing superalloys, consistent with a lattice misfit very near zero. With high levels of Ru, the addition of Cr also has a strong influence on partitioning. These investigations demonstrate that Ru and Cr control the lattice misfit, precipitate shape, and creep behavior, through the associated changes in the γ-γ′ phase equilibrium.     

Methodological fundamentals of computer-assisted designing of nickel-based superalloys

More than 180 Russian and foreign nickel superalloys are analyzed to develop regression models to find a relation between chemical composition and a number of the most important thermodynamic, structural, and strength parameters, which directly influence the high-temperature strength of the alloys. The high accuracy of constructing the characteristics of distribution of alloying elements between the γ and γ’ phases under scarce experimental data conditions is ensured by the application of bunch map analysis of random characteristics, which allowed the reliability of the calculated results to be significantly increased.     

中间退火对W25Re合金丝材加工性能的影响

研究了中间退火工艺参数（丝径、温度、速度）对W25Re合金丝材抗拉强度、组织及成品率的影响。有关结果表明，通过适当选取中间退火工艺参数，可改善W25Re合金丝材的加工性能，使合金坯料加工成D0．1mm细丝的成品率达60％，且断丝次数不超过3次。     

氩气雾化镍基粉末高温合金及粉末特性研究进展

概述了国内外镍基粉末高温合金的发展、氩气雾化制粉技术的特点、氩气雾化镍基高温合金粉末的特性和增材制造用镍基高温合金粉末的发展方向,重点介绍了镍基高温合金粉末的形貌与粒度控制、氧化特性、气体脱附行为和缺陷形成及控制措施。讨论了镍基高温合金粉末特性与合金缺陷之间的内在关系,总结了缺陷消除措施的研究进展,明确了未来粉末涡轮盘用氩气雾化镍基高温合金粉末质量优化的发展方向,并对高品质氩气雾化镍基高温合金粉末促进增材制造技术在航空航天领域的应用进行了展望。     

X-射线荧光光谱法分析中镍基高温合金中16种元素

用PANalytical MagiX Pro顺序型X射线荧光光谱仪,多系列镍基高温合金光谱标准样品拟合成一套校准曲线的方法,测定多种牌号镍基高温合金中的Al,Si,P,Ti,Ce,V,Cr,Mn,Fe,Co,W,Cu,Ta,Zr,Nb,Mo16种元素.采用SuperQ高级定量分析软件提供的数学模型对各元素的谱线干扰及基体效应进行校正,方法具有准确可靠、稳定性好、速度快等优点.     

Environmentally assisted,sustained-load crack growth in powder metallurgy nickel-based superalloys

To examine the influence of niobium (Nb) on sustained-load crack growth (SLCG) in oxygen, three powder metallurgy (P/M) nickel-based superalloys, with nominal compositions similar to IN100, but with 0, 2.5, and 5 wt pct of Nb, are used. These alloys are gamma-prime (γ’) strengthened and have comparable volume fractions (53 vol pct) of γ’ precipitates. The SLCG experiments are conducted in high-purity oxygen and argon at 873, 923, and 973 K. The environmental cracking sensitivity (ECS) for the alloys with 2.5 and 5 wt pct of Nb is consistent with that of INCONEL 718 and supports the previously identified role of Nb-rich carbides in enhancing crack growth. The susceptibility of the Nb-free alloy to oxygen, however, is much greater than expected. The apparent activation energy for crack growth in oxygen was found to depend on stress-intensity-factor (K) levels for the Nb-containing alloys and ranged from about 320 to 260 kJ/mol for K levels of 35 to 60 MPa√m. It was nearly independent of K at about 250 kJ/mol for the Nb-free alloy. The results are discussed in terms of the rate-controlling process and of the mechanism for crack-growth enhancement.     

失配性质对二维失配铝膜结构及位错形成的影响

采用三维分子动力学模拟方法,使用Ercolessi和Adams建立的嵌入原子法（EAM）多体势函数,模拟了二维失配铝膜晶体中失配位错的形成过程,研究了失配性质对二维失配铝膜结构及其形核机制的影响.结果显示：同等条件下,负失配度的临界厚度小于正失配度情况;负失配度较易出现失配位错;负失配度下位错的形成始于表层一个倒三角锥形的间隙原子团;正失配度下位错的形成始于表层原子的畸变区;结构稳定后,负失配度体系在表层挤出局部原子层;正失配度体系会出现塌陷.     

含Hf镍基粉末高温合金快速凝固粉末颗粒特性

采用扫描电镜、透射电镜及其附带的能谱仪和碳复型萃取技术等多种手段研究了不同Hf含量的FGH96合金粉末颗粒显微组织、枝晶间合金元素偏析和析出相.发现Hf含量可以改变粉末颗粒内部树枝晶、胞状长大晶和微晶凝固组织的比例,粉末的快速凝固组织形态主要取决于冷却速率和固液界面前沿温度梯度与长大速度的比值.不同Hf含量的FGH96合金粉末颗粒中,Nb、Ti、Zr和Al均富集于枝晶间,Co、Cr、W和Ni均富集于枝晶轴.当Hf质量分数为0.3%时,Ti、Nb、Zr、Hf等强碳化物形成元素的枝晶偏析程度最小.在快速凝固粉末颗粒中,Hf对氧含量比碳含量更敏感,优先形成更稳定的氧化物HfO₂.