掺杂硫对IN718合金性能的影响

研究了掺杂硫对ＩＮ７１８合金的影响,结果表明,硫使蠕变抗力和持久寿命降低,硫对ＩＮ７１８合金的有害作用具有明显的表面效应,一种可能的机制是硫加剧表面晶界在蠕变和持久试验中的氧化和开裂。     

磷含量对IN718合金持久和蠕变性能的影响

研究了不同含量的磷在ＩＮ７１８合金的作用。结果表明,磷对持久和蠕变性能有显著的影响,可提高ＩＮ７１８合金晶界抗蠕变形裂的能力,将磷含帅０．００３％提高至０．０３％,持久寿命先是增加而后降低,并在含磷０．０２５％年达到持久寿命峰值。磷对应力指数影响不大,但对表观蠕变激活能影响显著。磷的有益作用主要来自于抑制晶界扩散和改善晶界δ相。     

磷对IN718合金δ相的影响

研究了磷对ＩＮ７１８合金δ相的影响。结果表明：磷改善热处处理组织中δ相的形态和分布,显著抑制儿过程中δ相的生长,磷对δ相生长的抑制可与磷对矿散的阻碍作用有关。     

磷在变形IN718合金中的作用

研究了磷在变形ＩＮ７１８合金中的作用,结果表明,磷显著改善了该合金的持久性能,明显延缓蠕变进程,添加０．０２％磷可使表观蠕变激活能由６７８．６ｋＪ／ｍｏｌ提高到７４６．１Ｋｊ／ｍｏｌ,晶界扩散激活能由２７６．１ｋＪ／ｍｏｌ提高至３４９．８ｋＪ／ｍｏｌ,磷的作用起因于降低晶界能而偏聚于晶界,从而抑制晶界扩散,降低晶界结合力。     

磷对Inconel718形变合金力学性能的影响

对国内生产的低磷Ｉｎｃｏｎｅｌ７１８（Ｐ含量＜０．００１％）及常规Ｉｎｃｏｎｅｌ７１８（Ｐ含量为０．００８％～０．０１３％）形变合金锻件的力学性能进行了对比研究。结果表明,室温拉伸强度和高温拉伸强度的差异不大,然而低磷Ｉｎｃｏｎｅｌ７１８合金的高温塑性和６５０℃,６８６ＭＰａ的持久塑性明显降低;更为值得注意的是,低磷合金在疲劳、蠕变和疲劳／蠕变交互作用下的抗裂纹扩展能力都低于常规合金;而且低磷合金的５９５℃,８９５ＭＰａ缺口周期持久寿命有降低趋势。     

GH718合金氢渗透特性的研究

ＧＨ７１８合金氢渗透特性的研究徐坚，孙秀魁，刘清泉，陈文绣（中国科学院金属研究所，快速凝固非平衡合金国家重点实验室沈阳１１００１５）１前言ＧＨ７１８（ＩＮＣＯＮＥＬ７１８）合金广泛用作为涡轮叶片、氢燃发动机、核反应堆器壁等部件的材料．由于使用环境中氢...     

IN718合金蠕变的补偿效应

研究了Ｐ,Ｓ和Ｂ含量不同的ＩＮ７１８合金的蠕变性能。结果表明,普通多晶体的蠕变存在补偿效应。一无素通过影响表现蠕变激活能Ｑ和指九前因子ε０,从而影响稳态蠕变速弯ε＝ε０ｅ－Ｑ／ＲＴ,各度验合金的Ｑ与ε０遵守补偿定律Ｑ＝ＲＴｃｌｎε０＋Ｑ０,式中常数Ｑ０＝６８．１２ｋｊ／ｍｏｌ,补偿温度Ｔｃ≈８１０℃,Ｔｃ可能近皇ＩＮ７１８合金δ相快速形成的临界温度。     

γ″和γ′复合析出强化新型镍基高温合金的研究

通过ＩＮＣＯＮＥＬ７１８（ＧＨ１６９）合金中主要强化元素Ｎｂ、Ｔｉ、Ａｌ的调整获得γ″＋γ′相的复合析出，使其组织稳定性得以提高，突破了６５０℃的使用温度上限。在γ″和γ′复合析出强化的新型镍基合金中γ″在高温时聚集长大速率降低，γ″→δ转变延迟，高温组织稳定性提高，并且其拉伸、持久和蠕变性能都比ＩＮＣＯＮＥＬ７１８原型合金为优。新型合金成分范围基本上仍保持ＩＮＣＯＮＥＬ７１８合金的基础，当Ｎｂ含量在５０％～５３％（质量分数）时，Ａｌ＋Ｔｉ＋Ｎｂ的总量应控制为６５％～７５％（原子分数），且（Ａｌ＋Ｔｉ）／Ｎｂ的原子含量比在１１～１４之间。     

硫对Inconel718高温合金组织性能的影响

对不同硫含量的４炉Ｉｎｃｏｎｅｌ７１８合金进行力学性能测试及显微组织分析结果表明，硫具有严重的危害作用，表现在试样最终热处理后的６５０℃持久寿命和塑性的恶化和６５０℃高温拉伸塑性的降低。     

γ″和γ′复合析出强化新型镍基高温合金的研究

通过ＩＮＣＯＮＥＬ７１８（ＧＨ１６９）合金中主要强化元素Ｎｂ、Ｔｉ、Ａｌ的调整获得γ″＋γ′相的复合析出，使其组织稳定性得以提高，突破了６５０℃的使用温度上限。     

Strain-rate hardening behavior of superalloy IN718

In order to produce superior feed stock for the forging of turbine disks and other components, it is necessary to better understand the effect of deformation parameters on the hot deformation behavior of IN718 during thermomechanical processing. Superalloy IN718 is a strain-rate sensitive material. In the present work, isothermal constant speed compression tests of superalloy IN718 were conducted using a computer-controlled MTS machine at temperatures of from 960 to 1040°C, with initial strain rates of from 0.001 to 1.0 s⁻¹, to engineering strains of from 0.1 to 0.7. The variation of flow stress with initial strain rate was analyzed in the paper. It was found that there was an obvious power-law relationship between flow stress and initial strain rate. From the results of these tests, a mathematical model showing the strain-rate hardening behavior of superalloy IN718 at elevated temperatures was developed. At the same time, the flow stress calculated from the model was compared with experimental results and the effect of deformation parameters on the related coefficients was analyzed.     

Cu过渡层对激光增材制造TC4/IN718双金属结构组织性能的影响

钛合金和镍基合金各具有独特性能，二者的双金属结构在航空航天领域具有广泛的应用前景。由于2种金属的物理与化学性能差异较大，易在结合区域产生开裂。基于直接激光沉积（DLD）技术，分别制备了无过渡层和Cu过渡层的TC4/IN718双金属结构。测试分析结果表明，无过渡层双金属结构，结合区形成大量Ti-Ni脆性相，导致裂纹敏感性提高，产生开裂；Cu过渡层的双金属结构，在TC4与IN718之间形成Cu过渡区，限制TC4与IN718直接结合，降低裂纹敏感性，无裂纹等冶金缺陷产生，由于冶金反应与元素扩散的发生，在Cu过渡区中形成了少量Ti-Cu与微量Ti-Ni化合物相；化合物相在双金属结构中的产生，使Cu过渡区维氏硬度最高约为5801.6MPa，但远低于无过渡层双金属结构的维氏硬度（最高约为8281 MPa）。     

扫描间距对选区激光熔化IN718合金微观组织的影响

通过选区激光熔化(SLM)技术制备了IN718合金,利用X射线显微镜、X射线衍射仪、扫描电镜和电子背散射衍射等技术分析了IN718合金的致密性、相组成和晶粒形态以及取向关系。结果表明:SLM成形IN718合金的物相组成为面心立方结构的γ-Ni相与体心四方结构的γ″相,晶粒沿构建方向呈柱状晶。当激光扫描间距为100 μm时合金的致密度达到最高,当激光扫描间距为90 μm时,合金沿构建方向形成强<001>织构。     

CONSTITUTIVE RELATIONSHIP OF SUPERALLOY IN718

ＣＯＮＳＴＩＴＵＴＩＶＥＲＥＬＡＴＩＯＮＳＨＩＰＯＦＳＵＰＥＲＡＬＬＯＹＩＮ７１８Ｊ．Ｍ．Ｚｈａｎｇ;Ｌ．Ｚ．Ｍａ;Ｊ．Ｙ．Ｚｈｕａｎｇ;Ｑ．Ｄｅｎｇ;Ｊ．ＨＤｕａｎｄＺ．ＹＺｈｏｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＳｕｐｅｒａｌｌｏｙｓ,ＣｅｎｔｒａｌＩ...     

Distribution of Phosphorus and Its Effects on Precipitation Behaviors and Tensile Properties of IN718C Cast Superalloy

The effect of phosphorus on the precipitations of γ",γ' and δ phases and associated tensile properties in IN718C alloy are investigated in this study.It is revealed that P atoms are dissolved in the grain interior to a relatively high degree and hence influence the precipitation behaviors in the grain interior and improve the tensile strength of IN718C alloy.γ" and γ' phases did not precipitate in the alloy without P addition during air cooling,while γ" and γ' phases precipitated in the grain interior during air cooling in the alloys with P addition,and the amounts of γ" and γ' phases increased with increasing P content.Therefore,the Vickers micro-hardness in the as-cast state increased gradually with increasing P content.In double-aging state,the sizes of γ" and γ' phases in the alloys with P addition were larger than that in the alloy without P addition,while the sizes were invariable when the P content(wt%)was higher than 0.015.Therefore,the micro-hardness and tensile strength of IN718C alloy treated by double aging increased first and then kept invariable with increasing P content.The precipitations of δ phases both in the grain interior and on grain boundaries were inhibited by P markedly.The inhibitory effect of P on δ phase enhanced gradually with increasing content of P,but the plasticity increased first and then decreased.What is more,the crack tended to propagate into the matrix around the particles(Laves phases and NbC carbides)in the alloys without P addition at the beginning of the tensile fracture,while it tended to propagate along the interfaces between the matrix and those particles in the alloys with P addition,which resulted from the synthetical effect of P on γ" γ' and δ phases.     

二次固溶处理对IN718合金组织性能的影响

对IN718合金进行二次固溶处理,研究了二次固溶处理对其组织及高温拉伸性能的影响。结果表明,经二次固溶处理后,IN718合金组织中δ相含量较一次固溶增加,高温屈服强度降低。随二次固溶温度升高,δ相析出减少,高温屈服强度升高。     

Fatigue crack growth behavior of laser-annealed IN 718 alloy in hydrogen

The effect of hydrogen embrittlement on the fatigue crack growth of IN 718 plate and laser-annealed specimens in hydrogen containing environment were investigated. Although the differences in tensile strength and impact toughness between solution-annealed (S) and aged (A) IN 718 specimens were significant, the experimental results indicated that both specimens within the low ΔK regime exhibited a similar fatigue behavior. As the ΔK increased above 30 MPa , the solution-annealed specimen revealed a higher fatigue crack growth rate (FCGR) than the aged one. In general, the IN 718 alloy had a low sensitivity to hydrogen-enhanced fatigue crack growth, independent of hydrogen sources. Residual compressive stresses ahead of the crack tip were responsible for the improved resistance to fatigue crack growth in a laser-annealed specimen. For alloys with similar strength, IN 718 alloy trapped a huge amount of hydrogen in the matrix showing a less susceptibility to hydrogen-enhanced fatigue crack growth in comparison with the maraging steel. Additionally, fatigue-fractured appearance near crack initiation sites reveals quasi-cleavage fracture in embrittled specimens.