Hydrogen-induced cracking behaviors of Incoloy alloy 825

The effect of hydrogen on the fracture behaviors of Incoloy alloy 825 was investigated by means of slow strain rate testing (SSRT).Hydrogen was introduced into the sample by electrochemical charging.The results show that surface microcracks form gradually during aging at room temperature when desorption of hydrogen takes place after hydrogen charging at a current density of 5 mA/cm 2 for 24 h.SSRT shows that the increase of ductility loss is significantly obvious as the hydrogen charging current density inc...     

Carburization performance of Incoloy 800HT in CH4/H2 gas mixtures

Carburization performance of Incoloy 800HT has been studied after cyclic and isothermal exposures to CH₄/H₂ carburizing gas mixtures at high temperatures for 500 h. At 800 °C in 2% CH₄/H₂, Incoloy 800HT suffered external oxidation and carburization, the external continuous layer of reaction products consists primarily of Cr₇C₃, Mn_1.5Cr_1.5O₄, and FeCr₂O₄ with Fe(Cr, Al)₂O₄ as a minor phase. At 1100 °C in 10% CH₄/H₂, external carburization did not occur likely due to high carbon dissolution in the alloy substrate at this temperature. A thermodynamic analysis indicated that 1000 °C was an approximate critical temperature, below which the environment should result in mixed oxidizing/carburizing behavior, while above this temperature reducing carburizing behavior should occur. The experimental results approximately agree with the thermodynamic analysis. Metal dusting was not observed under highly carburizing conditions (a_C>1). The size and morphology of Cr-rich phases (or Cr-carbides) are both temperature- and time-dependent, while the external continuity is more temperature-dependent rather than time-dependent.     

Incoloy 800波纹管膨胀节开裂失效分析

金属波纹管膨胀节具有热补偿功能,应用越来越广,同时其失效开裂问题也日益显现.为此,从宏观形貌、化学成分、金相显微组织、SEM微现形貌方面,对开裂的Incoloy 800波纹管膨胀节进行了分析.结果表明,波纹管膨胀节开裂的原因是高轴向拉应力条件下的材料失稳破裂,并提出了相应的改进措施.     

Experimental Investigation of the A-TIG Welding Process of Incoloy 800H

This work attempts to investigate the influence of different flux powders in the activated-TIG welding process of the Incoloy 800H super alloy. Three different fluxes (SiO₂, ZnO, and 50% ZnO +50% SiO₂) were used and welded under the same conditions and process parameters. The oxide fluxes used were in the form of nanoparticle powders. The metallurgical characteristics and mechanical properties were analyzed, and it was found that the SiO₂ flux could increase the depth of penetration whereas a ZnO flux was detrimental to this effect. Although a SiO₂ flux increased the depth of penetration, it led to a sensitization issue in the grain boundary. The combination of the fluxes 50% ZnO +50% SiO₂ produced a moderate increase in the depth of penetration compared to ZnO flux-coated weldments, but revealed a dendritic structure in the weld region.     

800H合金长时间蠕变下的显微组织

对低负荷长时间蠕变试验下800H合金显微组织的研究表明:空洞在晶界M_(23)C_6碳化物的一侧形成,微裂纹通过一连串这样的小空洞而发展;晶界M_(23)C_6碳化物和相邻两晶粒之一有共格关系而与另一晶粒无共格界面,共格界面强化了晶界,这一强化作用可用蠕变激活能的提高来说明,晶界还有G相析出,但未发现合金中有γ'相的形成。合金能长时间保留网状的位错结构,晶界碳化物附近有位错塞积,亚晶界结构发展不充分,这与典型的回复蠕变是不同的。     

Incoloy825+12Cr2Mo1R复合板封头冲压加工研制

煤焦油深加工项目中的核心设备沥青预处理塔设计材料为Incoloy825(复层)+12Cr2Mo1R(基层)复合板。由于材料的特殊性和使用工况的复杂性,要求成形后封头即耐热又耐蚀。封头成形是本设备制造中的难点。采用高温热冲压成形和随后的正火加回火热处理,封头的各项技术指标达到了设计要求。文中介绍了复合板Incoloy825+12Cr2Mo1R材料特性,封头成形工艺,热处理工艺和合格指标。     

J‐Aggregates of Organic Dye Molecules Complexed with Iron Oxide Nanoparticles for Imaging‐Guided Photothermal Therapy Under 915‐nm Light

Recently, the development of nano‐theranostic agents aiming at imaging guided therapy has received great attention. In this work, a near‐infrared (NIR) heptamethine indocyanine dye, IR825, in the presence of cationic polymer, polyallylamine hydrochloride (PAH), forms J‐aggregates with red‐shifted and significantly enhanced absorbance. After further complexing with ultra‐small iron oxide nanoparticles (IONPs) and the followed functionalization with polyethylene glycol (PEG), the obtained IR825@PAH‐IONP‐PEG composite nanoparticles are highly stable in different physiological media. With a sharp absorbance peak, IR825@PAH‐IONP‐PEG can serve as an effective photothermal agent under laser irradiation at 915 nm, which appears to be optimal in photothermal therapy application considering its improved tissue penetration compared with 808‐nm light and much lower water heating in comparison to 980‐nm light. As revealed by magnetic resonance (MR) imaging, those nanoparticles after intravenous injection exhibit high tumor accumulation, which is then harnessed for in vivo photothermal ablation of tumors, achieving excellent therapeutic efficacy in a mouse tumor model. This study demonstrates for the first time that J‐aggregates of organic dye molecules are an interesting class of photothermal material, which when combined with other imageable nanoprobes could serve as a theranostic agent for imaging‐guided photothermal therapy of cancer.     

Investigation on Some Machinability Aspects of Inconel 825 During Dry Turning

In the current study, attempt has been made to investigate the influence of cutting speed (Vc) (51, 84, and 124 m/min) on various machining characteristics like chip morphology, chip thickness ratio, tool wear, surface, and sub-surface integrity during dry turning of Inconel 825. Comparable study was carried out using uncoated and commercially available chemical vapor deposition multilayer coated (TiN/TiCN/Al₂O₃/ZrCN) cemented carbide (ISO P30 grade) insert. Chip morphology consists of chip forms obtained at different cutting conditions. Serrated chips were observed when machining Inconel 825 with both types of tool with more serration in case of uncoated insert. The chip thickness ratio increased as cutting speed was increased. Use of multilayer coated tool also resulted in increase in chip thickness ratio. Rake and flank surfaces were examined with scanning electron microscope and optical microscope. Abrasion, adhesion, and diffusion wears were found to be dominating tool wear mechanism during dry machining of Inconel 825. The beneficial effect of coated tool over its uncoated counterpart was most prominent during machining at high cutting speed (Vc = 124 m/min). The surface and sub-surface integrity obtained with coated tool were superior to that while machining Inconel 825 with uncoated tool.     

电渣重熔高温合金渣系对冶金质量的影响

为控制Incoloy825合金中的Al、Ti含量,并减少电渣过程中氟化物的挥发。借助FactSage热力学软件,建立渣−金反应的热力学模型。设计出适宜控制Al、Ti含量的低氟渣系,探究了渣中组元与Al₂O₃和TiO₂活度比的关系,并通过高温渣–金平衡实验进行验证。结果表明：当渣中CaO和Al₂O₃含量增加,导致2O₃ and TiO₂ was studied, the result was verified by a high-temperature slag metal equilibrium experiment. The results show that the CaO and Al₂O₃ contents in slag increases with increase in the 相似文献