Inconel625高温合金J-C本构建模

为了研究Inconel625高温合金在较高温度和应变率变化范围内的热变形行为,采用CSS电子万能试验机和分离式霍普金森压杆试验装置对Inconel625高温合金进行准静态试验和霍普金森压杆试验,在温度为20~800℃、应变率为0.001~8000 s~(-1)范围内得到Inconel625高温合金的真实应力—应变曲线。结果表明:随着温度的升高,Inconel625高温合金的流动应力与屈服应力并不单一地随应变率增大而增大,同一温度条件下,随着应变率的增加,Inconel625高温合金的真实应力先增大后减小(分界线是应变率为6000 s~(-1));同一应变率条件下,Inconel625高温合金的真实应力随着温度的升高而减小。基于Johnson-Cook模型对其真实应力-应变曲线进行拟合分析,经过计算得到模型的预测值与实验值的相关性和绝对误差,并进一步改进Inconel625高温合金的Johnson-Cook本构模型,使模型能够更好地反映Inconel625高温合金在较高温度和应变率变化范围内的热变形规律。     

高温高速环境下Inconel625合金热变形行为的数学描述

研究了Inconel625合金的热变形行为。结果表明,在变形温度为1 000~1 200℃,应变速率为10~80 s-1条件下,Inconel625合金的热变形行为呈现出持续硬化+动态软化的过程。所建立的高温高速下Inconel625合金的热变形本构方程,能够较好的表达应变速率以及变形温度和峰值应力的关系。     

Nimonic101高温合金室温力学性能的改善

直径为125 mm的Nimonic101高温合金棒材抗拉强度不合格.为提高Nimonic101合金的室温力学性能,采用汽轮机叶片的工艺对Nimonic101合金进行了锻造,并采用不同工艺固溶处理、时效和介于固溶处理和时效之间的中间热处理.此后检测了Nimonic101合金的显微组织和力学性能.结果表明:(a)由棒材锻造...     

Inconel 625合金国内外研究现状综述

Inconel 625因其优异的综合性能广泛应用于各种工业领域。随着各行业的发展，对Inconel 625合金的性能要求越来越高，因此进一步改善Inconel 625合金的组织及性能非常必要。本文总结了近7年国内外学者对Inconel 625合金成型制备、组织性能、熔盐腐蚀等方面的研究，其中成型方法从3D打印技术（即增材制造）、表面改性技术等方面综述；性能方面主要总结了化学成分和热处理工艺；熔盐腐蚀方面重点讨论了氟化物盐、硝酸盐、碳酸盐、硫酸盐等。最后，提出了Inconel 625合金未来的发展前景，为以后Inconel 625的研究提供了实际性的指导。     

烧结温度对多孔Inconel625合金性能的影响

Inconel625有着优异的耐蚀性与高温力学性能,被广泛用于航空航天、石油化工、核工业等领域。多孔材料有着轻质化与优良的透过性能常被用于过滤材料。本文旨在制备出耐蚀性良好的过滤材料,利用粉末冶金技术制备出兼具Inconel625合金本身特性与功能特性的多孔Inconel625合金。实验采用100~200μm粒度的合金粉末,通过模压-气氛烧结的工艺制备了多孔Inconel625合金,并对不同烧结温度下的合金做了形貌表征与性能评价。结果表明,在1240℃烧结温度下合金烧结颈发育良好,孔隙球化率高,此时透气度满足服役性能需求,可作为高温气液过滤材料使用,该温度下合金剪切性能达到最优,最大剪切力为51.0KN,也为后续进一步的研究提供了参考依据。     

Inconel 625合金高温高速热变形行为

通过等温热压缩实验研究Inconel 625合金的高温高速热变形行为,获得了合金在温度为1000～1200℃、应变速率为1～80 s-1的条件下的真应力-应变曲线,并在考虑变形热效应的基础上对真应力-应变曲线进行了修正。对修正后的峰值应力进行线性回归,得到材料的材料常数:Q=442.97 kJ/mol,n=4.49,α=0.0029 MPa-1。通过非线性回归建立了Inconel 625合金在高温高速条件下的本构模型。     

不同层错能镍基合金梯度结构的构筑与组织演变

以Inconel625合金作为参照对象,基于界面调控的合金设计思路,采用热力学软件设计出一种低合金化低层错能的镍基变形高温合金。通过表面机械碾压处理（SMGT）技术,研究层错能对镍基合金梯度结构的演化机制和晶粒细化机制的影响规律。结果表明,经SMGT处理在Inconel 625合金、M1和M2合金表层中分别制备出了450、300和250μm厚的梯度结构层。此外,不同合金梯度组织的演化机制也不同,在Inconel 625合金中,随着应变的逐渐增加,其微观结构细化机制逐步从位错分割机制转变为剪切带和孪晶分割机制;而在M合金中,以形变孪晶分割机制为主。因此,基于设计理念及对应的组织演变机制,可为低层错能镍基变形高温合金的成分设计提供一定的参考。     

Inconel625合金高速热变形动态再结晶的临界条件

通过等温热压缩试验获得Inconel625合金在变形温度为1000～1200℃,应变速率为1～80S^-1条件下的真应力-应变曲线,利用加工硬化率,结合lnθ-ε曲线上的拐点判据及-δ（1nθ）／δε-ε曲线上的最小值,来研究Inconel625合金动态再结晶的临界条件。结果表明,在该实验条件下,Inconel625合金的lnθε曲线均出现拐点特征,对应的-δ（lnθ）／δε-ε曲线出现最小值,该最小值处对应的应变即为临界应变;临界应变随应变速率的增大和变形温度的降低而增加,并且临界应变和峰值应变之间有一定的关系,即εc=0．69εp;动态再结晶时临界应变的预测模型可以表示为εc=4．41×10^-4Z^0.14261。     

HVAF喷涂Inconel625涂层在生物质发电环境的高温腐蚀行为

秸秆等生物质焚烧发电时产生的含氯气体和碱金属氯化物腐蚀使受热面金属管道的服役寿命比煤电机组显著降低。 管材表面堆焊镍基耐腐蚀合金的技术尽管可显著提高管道服役寿命,但存在工作效率低、不适合现场施工、管道热变形等诸多问题。 采用可现场施工的空气超音速火焰喷涂(HVAF)在 TP347H 耐热钢表面,制备了 Inconel 镍基耐高温腐蚀涂层,研究了 TP347H 耐热钢喷涂 Inconel 625 合金涂层前后的长期高温腐蚀特性(550 ℃ ,500 h),验证了 HVAF Inconel 625 合金涂层的高温含氯腐蚀防护作用。 显微观察结果表明,优化工艺参数条件下 HVAF 涂层组织致密、 孔隙率低至 0. 72%,与基材结合良好。 腐蚀增重结果表明,采用 HVAF 制备 Inconel 625 合金涂层后,TP347H 耐热钢的腐蚀增重降低 7. 6 倍,耐腐蚀性能显著提升。 冲蚀试验结果表明,HVAF Inconel 625 合金涂层在最初阶段由于表层凸起颗粒的剥落而冲蚀性能极低,进入稳定阶段后耐冲蚀性能提高,与 TP347H 基材的耐冲蚀性能相当。     

φ530 mm Inconel 625合金铸锭组织及其在加热过程的变化

研究了φ530 mm Inconel 625合金铸锭的组织及其在加热过程中的组织转变。结果表明,除了基体相外,铸态合金由于凝固偏析还会依次形成NbC、Laves、δ-Ni_3Nb以及γ″等第二相。其中δ-Ni_3Nb以及γ″相经1100℃固溶就能完全溶入基体中,Laves相在1140℃开始溶入基体。在1185℃时,Inconel 625合金发生初熔,为了提高合金的均匀性,合金合适的扩散退火应为1180℃。     

Corrosion behavior of Ni-Cr-base commercial alloys in flowing Ar-42.6%O2-14.7%Br2 gas mixture at 700°C

Corrosion behavior of Ni-Cr-Base commercial alloys has been investigated in an argon-42.6% oxygen-14.7% bromine gas mixture at 700°C which was one of the environments encountered in the UT -3 thermochemical water decomposition reaction process to produce hydrogen. The test alloys were Inconel 600, Hastelloy C-276, Inconel 625, and Nimonic 80A. Two-dimensional thermodynamic phase stability diagrams were constructed for nickel, chromium, iron, tungsten, cobalt, titanium, and aluminium to predict the condensed corrosion products that are stable with respect to the representative alloying elements when the alloy is exposed to the argon-42.6% oxygen-14.7% bromine gas mixture at 700°C. The oxides were thermodynamically stable phases with respect to the corresponding metals. Post-reaction treatment of test alloys included discontinuous mass-change measurements, scanning electron microscopy (SEM), electron probe micro-analysis (EPMA) for morphological and compositional investigation of the corrosion products, and the X-ray diffraction (XRD) for phase identification. XRD identified oxides and spinels as corrosion products but low-melting metal bromides were also detected for all alloys with deleterious effects on high-temperature properties of these alloys during exposure to the environment. The poor corrosion resistance of Inconel 600 and Hastelloy C-276 was mainly caused by the cracking and spalling of iron and nickel-rich oxides and further growth of various metal bromides beneath the oxide scale following prolonged exposure. Inconel 625 and Nimonic 80A alloys performed better than Inconel 600 and Hastelloy C-276, mainly because of their aluminium alloying element and lower iron content.     

Evaluation of the Low Heat Input Process for Weld Repair of Nickel-Base Superalloys

The repair of turbine blades and vanes commonly involves gas tungsten arc welding or an equivalent process, but unfortunately these components are often susceptible to heat-affected zone (HAZ) cracking during the weld repair process. This is a major problem especially in cast alloys due to their coarse-grain size and where the (Al + Ti) contents is in excess of 3-4%; vacuum brazing is also used but mainly on low stress non-rotating components such as vanes. Micro-welding has the potential to deposit small amounts of filler at low heat input levels with minimum HAZ and thus is an attractive process for depositing a quality weld. As with conventional fusion processes, the filler alloy is deposited by the generation of a low power arc between a consumable electrode and the substrate. The low heat input of this process offers unique advantages over more common welding processes such as gas tungsten arc, plasma arc, laser, and electron beam welding. In this study, the low heat input characteristic of micro-welding has been used to simulate weld repair using Inconel (IN) (Inconel and IN are trademarks of INCO Alloys International) 625, Rene (Rene is a trademark of General Electric Company) 41, Nimonic (Nimonic is a trademark of INCO Alloys International) 105 and Inconel 738LC filler alloys, to a cast Inconel 738LC substrate. The effect of micro-welding process parameters on the deposition rate, coating quality, and substrate has been investigated.     

Corrosion behaviour of Ni-based superalloys in molten FLiNaK salts

High-temperature corrosion tests of alloys, Nimonic 80A, Inconel 718 and Inconel C-276, were investigated at 680°C in molten alkali fluoride salt (LiF–NaF–KF: 46.5–11.5–42%) environment. In this work, techniques included were weight loss measurements and potentiodynamic polarisation curves measurements. Inconel C-276 and Inconel 718 showed better corrosion resistance, while Nimonic 80A exhibited comparatively lower corrosion resistance. The high-temperature corrosion behaviour was observed using measurements of the oxide morphology and thickness. The corrosion rates were determined by recording the weight changes of the sample alloys at different time intervals. Microstructural examination showed the depletion of Cr near the surface of the alloys and hence the significant weight loss in the early stages of corrosion tests. The corrosion mechanism of the alloys is discussed in detail.     

Effect of dilution on the behavior of solidification cracking in PTAW overlay deposit on Ni-Base superalloys

In this study, the effects of dilution on the solidification cracking susceptibility of PTAW (Plasma Transferred Arc Welding) Inconel 625 and 718 overlay on Nimonic 80A were observed. In order to evaluate solidification cracking susceptibility, the Varestraint test was utilized. A possible mechanism of solidification cracking was suggested on the basis of microstructural examination and thermal analysis. The present study showed that the solidification temperature range and the amount and distribution of γ/NbC and γ/Laves eutectic phases formed along the solidification grain boundaries. As dilution increased, the C/Nb ratio increased and the amount of eutectic phases decreased. In addition, the solidification temperature range decreased with increasing dilution in each overlay.     

Portevin–Le Chatelier Effect in Nimonic 263 Superalloy

The Portevin–Le Chatelier(PLC) effect in the Nimonic 263 superalloy was investigated by tensile test at a wide temperature ranges from 293 to 1033 K and strain rates between 0.1 and 6.25 9 10-6s-1. Simple binary alloys Ni-0.4C, Ni-24 Cr and Ni-5(8)Mo were also tested in order to identify which elements were responsible for the PLC effect in the Nimonic 263 alloy. The results demonstrated that for Nimonic 263 alloy, PLC effect occurred at certain temperatures and low strain rates. Normal PLC effect exhibiting type-A and-(A + B) serrations was attributed to the enhanced solute diffusion with increasing temperature, while inverse PLC effect with type-C serration was caused by unlocking process.The activation energy for the normal PLC effect was calculated to be 68 k J/mol, and diffusion of substitutional solutes such as Cr and Mo was identified to be responsible for the PLC effect. In comparison with the PLC effect in simple binary alloys, solute atmospheres formed by different kinds of atoms in Nimonic 263 alloy work more effectively, increasing locking strength and corresponding mean stress drop magnitude.     

30CrMo合金表面堆焊Inconel625镍基合金的耐腐蚀性能

为了解决石油、天然气井口装置在高含硫介质中的强腐蚀问题,以30CrMo钢作采油树的阀体或阀盖材料,在其表面堆焊两层Inconel625镍基合金。采用全浸式均匀腐蚀试验测定堆焊层的腐蚀速率。结果表明,Inconel625镍基合金堆焊层的腐蚀速率约为30CrMo钢的腐蚀速率的1／8,Inconel625镍基合金具有良好的抗...     

Das Korrosionsverhalten der Nickelbasislegierung Inconel 625

The corrosion behaviour of the nickel-based alloy Inconel 625 Due to its high resistance to corrosion by reactor coolants, water vapour and liquid sodium, the new high-temperature resistant nickel alloy Inconel 625 is well suited as fuel cladding material for a reactor of high energy density. Up to above 800° C, the scaling resistance in air is good. In electrolyte solutions, the general corrosion under conditions where a passivation layer cannot be formed or maintained is relatively slow. In accordance with expectations, Inconel 625 is not subject to intercrystalline corrosion by Strauss solutions even in the thermally sensitized condition, and even the reaction with nitric acid containing Cr^VI ions is not so much intergranular but superficial. If the material, together with V2A steel, is in contact with liquid sodium of 600° C, it is prone to chemical mass transfer. As a result, there occur precipitations of a new crystalline phase at the grain boundaries of the the Inconel 625 surface.     

Flow Behavior and Microstructures of Inconel 625 Superalloy at the Elevated Temperature

The deformation behavior of Inconel 625 superalloy was investigated by means of hot compression tests. The flow stress curves were obtained in the temperature and strain rate ranges of 950-1200 ℃ and 0.01-10 s-1, respectively. Optical microscopy was used to evaluate the microstructural evolution of the alloy under different conditions examined. The results show that the flow stress decreases with decreasing strain rate and increasing temperature, and the activation energy is about 654.502 kJ/mol. Microstructure observations show that with increasing temperature, the sizes and volume fraction of dynamic recrystallization (DRX) grains increase. The strain has no remarkably effect on the sizes of DRX grains, but with increasing strain the volume fraction of DRX grains increases. During hot compression of Inconel 625 superalloy at elevated temperature, the occurrence of DRX was the main softening mechanism. The DRX mechanism of Inconel 625 superalloy can be mainly attributed to the discontinuous dynamic recrystallization (DDRX).     

TiC含量对激光选区熔化Inconel 625合金微观组织及表面摩擦磨损性能的影响

为了提高3D打印镍基高温合金强度、硬度及耐磨性能,使用激光选区熔化技术(Selective laser melting,SLM)制备添加不同质量分数TiC增强Inconel 625合金材料,并对比添加不同质量分数TiC(4 wt.%和8 wt.%)所制备的SLM TiC/Inconel 625试样的摩擦磨损性能。结合X射线衍射仪(XRD),金相显微镜(OM),扫描电子显微镜(SEM)及能谱分析(EDS)等材料表征手段对TiC/Inconel 625试样的物相分布,微观组织结构及磨损前后的元素分布进行对比分析。结果表明,随着TiC含量的增高,SLM TiC/Inconel 625硬度从325 HV_(0.2)(不含TiC)升高到了587 HV_(0.2)(SLM 8 wt.%TiC/Inconel 625),磨损率也由22.4×10~(-5)mm~3/(N·m)下降为9.8×10~(-5)mm~3/(N·m)。其中,平均摩擦磨损系数最小的为SLM 4 wt.%Ti C/Inconel 625 (COF=0.47)。综合对比可以发现通过添加适量的TiC颗粒可以有限改善SLM Inconel 625的硬度及耐磨损性能。