多弧离子镀NiCrAlY涂层与搪瓷基复合涂层的抗热震行为对比研究

以K444镍基高温合金为基体,采用多弧离子镀法制备了NiCrAlY涂层、喷涂-烧结法制备了搪瓷基复合涂层,并对比研究了2种涂层的抗热震性能。热震实验高温段温度为900℃。高温段保温1.5h后经水或空气冷却为一个热震循环。结果表明,NiCrAlY涂层的抗热震性能较差。当冷却介质为水时,水淬热震30cyc后,涂层表面氧化膜开裂明显,且有个别裂纹已穿透氧化膜,扩展至涂层内部;而搪瓷基复合涂层的抗热震性能非常优异。热震后,涂层表面及内部均未发现裂纹,涂层和基体界面结合良好。经分析,其优良的抗热震性能源于:(1)搪瓷釉热膨胀系数与高温合金基体匹配度高;(2)纳米Ni和NiCrAlY金属颗粒的加入进一步增大涂层热膨胀系数的同时,还提高了搪瓷的韧塑性。     

四种典型高温防护涂层的抗氧化性能

目的系统地评价典型高温防护涂层的抗高温氧化性能,并分析其失效机制。方法通过对比普通Ni Al涂层、NiCrAlY涂层、Pt改性Ni Al涂层以及Pt+Hf共改性Ni Al涂层等四种典型高温防护涂层在1100℃的恒温氧化行为,从氧化过程中的氧化增重、组织结构演变规律等角度出发,分析了四种涂层在高温氧化过程中的抗氧化性能以及氧化失效规律。结果四种涂层在1100℃恒温氧化过程中的增重均符合抛物线规律。普通Ni Al涂层氧化膜粘附性能较差,氧化膜快速剥落,涂层退化最快。NiCrAlY涂层中Y元素在氧化膜/涂层界面形成"钉扎"作用,显著提高氧化膜的粘附性能,但由于涂层内部Al元素含量降低,涂层1100℃氧化300 h后基本失效。Pt改性Ni Al涂层的氧化膜较为完整,但氧化膜起伏严重。Pt+Hf共改性Ni Al涂层的氧化膜均匀完整且无明显起伏,具有综合最优的抗高温氧化性能。结论四种涂层的抗高温氧化性能排序为:Pt+Hf共改性Ni Al Pt改性NiAl普通Ni AlNiCrAlY。     

共渗制备NiCrAlY涂层及抗高温腐蚀研究

采用热扩散的方法在高温合金K417G基体上制备了NiCrAlY涂层,经测定,涂层以β–NiAl相为主,Cr以固溶态和AlCr(x)相同时存在。1000和1100℃恒温氧化试验表明,NiCrAlY涂层显著提高了合金的抗氧化性,氧化膜致密稳定的Al2O3为主,300h后氧化膜没有明显的剥落。对基体合金和涂层试样进行了900℃,NaCl/Na2SO4(25:75)融盐环境的热腐蚀试验。结果表明,NiCrAlY涂层氧化膜完整,涂层内硫化物含量低,有效提高了抗热腐蚀性能。     

渗铝改性离子镀NiCrAlY涂层的高温热腐蚀行为

为了进一步改善离子镀NiCrAlY涂层的抗热腐蚀性能,采用粉末包埋法在离子镀NiCrAlY涂层表面上进行渗铝,研究了涂层渗铝前后在850℃含氯硫酸盐膜下的热腐蚀行为.结果表明:在25%NaCl 75%Na2SO4熔盐中850℃热腐蚀40h时,未渗铝的NiCrAlY涂层生成的是外层以Cr2O3为主的氧化膜,渗铝后的NiCrAlY涂层仅生成一层Al2O3膜;未渗铝的NiCrAlY涂层在腐蚀50h后失去保护作用,而渗铝涂层在腐蚀100h后表面仍形成以Al2O3为主的保护膜.因此,渗铝处理可以明显提高原涂层的抗热腐蚀性能.     

γ-TiAl表面NiCrAlY/Al复合涂层的高温氧化行为

采用磁控溅射和电弧离子镀技术在γ-TiAl合金表面制备NiCrAlY/Al复合涂层,研究了复合涂层对提高γ-TiAl合金抗高温氧化性能的作用机理。经950℃恒温氧化100 h后,涂层表面未发现裂纹和脱落,涂层试样氧化增重值较基体大幅减小。对氧化层进行了SEM、EDS和XRD分析,结果表明无保护涂层的基体γ-TiAl合金表层疏松多孔,无法抵抗高温环境下氧气对基体合金的侵蚀。复合涂层表面的NiCrAlY镀层在氧化过程中形成了Cr2O3,α-Al2O3和β-NiAl相组成的致密防护涂层,阻隔了氧气与基体的接触,中间的Al层为表层持续生成Al2O3提供了Al源。NiCrAlY/Al复合涂层显著提高了基体在950℃下的抗高温氧化性能。     

铝合金压铸模具钢表面涂层改性研究

采用超音速火焰喷涂复合金属粉末对铝合金压铸模具H13钢进行表面涂层改性,并进行涂层表面性能、模具钢试样的耐磨损性能、抗高温氧化性能和热疲劳性能测试与分析。结果表明,超音速火焰喷涂复合金属粉末表面涂层改性显著改善了模具钢的耐磨损性能、抗高温氧化性能和热疲劳性能。与未进行表面涂层改性相比,表面涂层改性使其20℃、250℃和500℃磨损体积分别减小了85.9%、90.2%和89.6%;500℃高温氧化100 h后的单位面积质量增重减少86.6%;热疲劳裂纹级别从7级变为2级。     

两种MCrAlY涂层与DD98M合金的互扩散行为

为研究MCrAlY涂层与DD98M合金的互扩散行为,采用多弧离子镀技术在DD98M合金表面制备了NiCrAlY与NiCoCrAlY涂层,运用XRD、SEM/EDS、EPMA、TEM等方法分别分析了两种MCrAlY涂层对DD98M合金恒温氧化及互扩散行为的影响。结果表明:在1 050℃氧化100 h后,NiCrAlY和NiCoCrAlY涂层表面均形成了一层连续致密的以α-Al2O3为主的保护膜,显著提高了DD98M合金的抗氧化性能。两种MCrAlY涂层与DD98M合金之间形成了因互扩散而导致的互扩散区(IDZ);在NiCoCrAlY涂层试样中还形成了二次反应区(SRZ),但在NiCrAlY涂层试样中却并未发现。NiCoCrAlY涂层试样形成的SRZ中析出了很多针状与颗粒状的μ-TCP相;NiCrAlY涂层试样,合金基体γ/γ′结构中γ′相的体积分数没有明显增加,基体的化学组成与原始成分相比也没有发生明显改变,因此抑制了SRZ的形成。     

Nb-Hf合金表面Si-Ti-Cr硅化物涂层在恒温氧化和热震中的高温抗氧化性能（英文）

为了提高Nb-Hf合金的高温抗氧化性能,采用浆料烧结和高温渗透制备了Si-Ti-Cr硅化物涂层。分析了Si-Ti-Cr硅化物包覆的Nb-Hf合金样品在恒温氧化和高温热震条件下的抗氧化性能,揭示了Si-Ti-Cr涂层高温恒温氧化和高温热震条件下的失效机理。结果表明,在1800℃恒温氧化5 h条件下,涂层的增重为7 mg/cm²;在1700℃热震循环50周次和恒温氧化5 h条件下,涂层的最大增重为1.8mg/cm²。硅化物涂层在1800℃恒温氧化环境下和1700℃热震/恒温氧化环境下具有优异的抗氧化性能。     

Ti6Al4V钛合金表面Al_2O_3颗粒改性微弧氧化涂层制备及性能（英文）

通过在磷酸盐电解液中加入Al_2O_3陶瓷颗粒,使得在Ti6Al4V钛合金表面的微弧氧化涂层结构和性能得到改性。涂层的结构和性能通过扫描电镜和XRD进行表征和测试,涂层的抗高温氧化性能和热震性能通过高温热循环氧化试验和热震试验进行测试。结果表明,通过在电解液中添加Al_2O_3陶瓷颗粒,涂层由Al_2TiO_5和TiO_2组成,涂层更为致密,表现出更为优异的抗高温氧化和热震性能。电解液中游动的Al_2O_3陶瓷颗粒在微弧氧化过程中被吸入到样品表面并进入涂层,涂层的结构和性能得到改性。     

先进高温热障涂层用高性能粘接层制备及研究进展

热障涂层能显著提高航空发动机的效率和推重比,具备保护关键热端部件(例如涡轮叶片)能力而获得广泛运用,其构成一般由外表面的陶瓷隔热层和抗高温氧化的中间粘接层组成。在热障涂层体系中,粘接层抗高温氧化性能的好坏直接决定了热障涂层体系的服役性能和寿命,因此受到相关研究者的关注。金属Pt改性的粘接层具有优异的抗高温氧化和热腐蚀综合性能,特别是表面生成的连续致密Al2O3氧化膜抗剥落性强,是高温防护金属粘结层的优选方案。本文重点介绍了Pt改性MCrAlY粘接层和Pt改性铝化物涂层的研究现状和进展,并且论述了制备方法与原理及其特点,对先进Pt改性粘接层的发展趋势进行了展望。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.