强流脉冲电子束作用下镍基高温合金GH3039表面铬合金化及其抗高温氧化性能研究

目的改善GH3039合金的抗高温氧化性能。方法在GH3039合金表面涂抹Cr粉末,然后借助于强流脉冲电子束装置(简称HCPEB)对该合金表面进行相应的处理,而后分别使用X射线衍射仪(XRD)与扫描电子显微镜(SEM)对合金表面进行观察,对比处理前后的物相和微观结构变化,然后以850℃恒温环境为基础,对样品合金化前后的氧化动力学与氧化机制进行相应的测试与分析。结果该合金在HCPEB辐照处理后,其表层已经形成了相应的滑移带,表层晶粒显著细化,尤其是30次辐照样品中形成了尺寸约为100 nm的纳米晶结构。恒温氧化试验的测试结果显示,通过100 h的氧化处理,原始样品氧化增重数值最大,与此同时生成的氧化膜整体偏厚,达到6μm,有一定程度的裂纹与孔洞,基体发生了严重的内氧化。通过辐照处理30次后的合金化样品,氧化100 h后的增重数值最小,由此生成的氧化膜厚度仅仅约为3μm,同时氧化膜的主要构成为氧化铬,该氧化膜还呈现出连续生长属性,相应结构具有致密性且没有剥落,对基体有较为明显的保护功能。结论HCPEB辐照可以将Cr原子熔入GH3039合金表层,快速实现Cr表面合金化。合金表面Cr含量的提高以及在微结构促进元素扩散的共同作用下,该合金抗高温氧化性能得到显著优化。     

预氧化温度对GH3128合金抗高温循环氧化性能的影响

采用热重法并结合SEM、EDAX等分析手段,研究了预氧化温度对GH3128合金抗高温(1100℃)循环氧化性能的影响。结果表明:在适当温度下进行预氧化处理可有效提高合金的抗高温循环氧化性能。GH3128合金经预氧化处理后抗高温循环氧化性能的优劣主要取决于两种因素的综合作用,其一是合金表面元素Cr的选择性氧化,形成致密均匀的保护性预氧化膜,提高合金抗高温循环氧化性能;其二是合金中元素Ti、Cr的晶界偏析加剧,加速晶界氧化并导致显微裂纹等缺陷产生,降低合金的抗高温循环氧化性能。900℃预氧化处理的GH3128合金试样具有最佳的抗高温循环氧化性能,该温度下预氧化膜形成较好且合金元素Ti、Cr的晶界偏析作用相对较弱。     

强流脉冲电子束表面改性30SiMn2MoVA钢的显微组织

研究了不同照射次数强流脉冲电子束表面处理30SiMn2MoVA钢的显微组织。结果表明,经强流脉冲电子束处理后试样表面出现了形状各异、大小不一、分布不均的熔坑;随着照射次数增加,熔坑数量先减少后增加。当照射30次时,合金表面的熔坑最少,在表层形成了一层厚度约8μm的均匀重熔层。合金表层的组织发生了相变,产生了针状马氏体和残余奥氏体。     

喷丸与振动光饰复合处理对GH4169高温合金疲劳性能的影响

本文对比研究了喷丸和喷丸与振动光饰复合处理对GH4169高温合金疲劳性能的影响,利用扫描电子显微镜、粗糙度仪、显微硬度计、X射线应力测试仪分析和测试了试样的表面形貌、表层组织、粗糙度、显微硬度、残余应力场,探讨了表面完整性与疲劳性能的内在联系及作用机制。结果表明复合处理对GH4169合金疲劳性能的改善效果比单独喷丸强化处理更好;复合处理使GH4169高温合金的常温疲劳强度提高了21.6％;500℃预加热100h处理使复合强化GH4169高温合金疲劳强度降低了6％,但仍较未喷丸处理状态提高了14.29％,即复合处理能够有效改善GH4169高温合金常温～500℃高温工况下的抗疲劳性能。     

GH80A经强流脉冲电子束改性后的高温氧化行为研究

目的 提高燃气轮机叶片材料镍基高温合金GH80A的抗高温氧化性能。方法 利用强流脉冲电子束（High-Current Pulsed Electron Beam, HCPEB）技术对GH80A合金进行表面处理。研究HCPEB辐照前后GH80A的微观结构变化及在850 ℃恒温氧化后的氧化动力学行为及氧化机制。利用光学显微镜、X射线衍射仪和扫描电子显微镜对HCPEB诱发的微观结构和氧化产物进行了表征。结果 HCPEB辐照后,GH80A合金表面发生熔化,形成厚约3 μm的重熔层,重熔层内形成大量的位错滑移,且晶粒明显得到细化。850 ℃高温氧化实验结果表明,氧化100 h后,原始样品氧化增重最大,生成的氧化膜较厚,且存在大量裂纹,所生成的Cr2O3发生了挥发,导致氧化膜疏松多孔,基体发生了严重的内氧化。HCPEB辐照20次后,样品氧化增重最小,100 h氧化后形成的氧化膜主要由外层TiO2和内层Cr2O3构成。外层连续致密的TiO2抑制了保护性氧化膜Cr2O3的挥发,因此生成的Cr2O3氧化膜连续、致密、无剥落,对基体起保护作用。结论 HCPEB辐照后,GH80A合金的抗高温氧化性能明显提升,20次辐照样品的抗高温氧化性能最佳。     

镍基高温合金GH202表面纳米陶瓷涂层抗高温氧化性能研究

为了弥补高温合金抗高温氧化性能的不足,解决高温力学性能与抗高温氧化性之间的矛盾,在高温合金GH202合金表面增加含纳米高温陶瓷涂层CXM98-1,通过氧化动力学实验和能谱分析技术对涂层/基体合金体系的抗高温氧化性能进行了研究.实验结果得出:含纳米陶瓷涂层能有效的阻滞合金的高温氧化进程,极大的提高了合金的耐高温抗氧化性能.不论有无涂层,在900℃长时间扩散退火过程中,氧均通过涂层或金属表面向基体合金进行扩散,基体合金中的Cr、Al元素向涂层/基体合金界面上坡扩散,环境中氧原子通过涂层向基体合金扩散,在界面处靠涂层一侧主要形成Cr2O3扩散层,界面的基体一侧主要形成Al2O3晶间氧化层;有涂层与无涂层试样的区别在于氧的扩散速率和扩散通量存在快慢、大小的差别.     

强流脉冲电子束表面改性 1. 2344 钢的显微组织和性能

目的在1.2344钢表面获得一层硬度较高的强化层。方法利用强流脉冲电子束技术,在相同的加速电压下,采用不同的脉冲次数对1.2344钢表面进行改性处理,研究处理前后样品的表层显微组织和性能变化规律。结果经强流脉冲电子束处理后,试样表面形成了形状各异、大小不一、分布不均的熔坑,并且随着脉冲次数的增加,熔坑数量逐渐减少,熔坑的直径变大。当脉冲次数大于50次时,试样表面出现奥氏体相,表面显微硬度提高了14.5%。结论强流脉冲电子束处理可使试样表层的晶粒变小,晶粒细化和表面宏观残余应力的共同作用促使试样显微硬度增加。     

高压富氧下几种高温合金的燃烧特征和性能研究

利用高压富氧点燃设备,在氧气压力为2.0MPa、氧气浓度为99%的条件下,对GH169、GH202、GH586三种航天用典型合金进行了抗燃烧性能测试和特征研究,采用光镜、扫描电镜对燃烧产物的组织进行了分析。结果表明,合金在试验条件下均被点燃,其抗燃烧能力和燃烧持续时间从高到低依次为GH202、GH586、GH169;合金的燃烧产物主要由熔化团聚体和渣料组成,且燃烧后形成了大量的空洞组织,燃烧试样形貌由疏松氧化层、熔化层和基体构成;合金具有低的燃烧热以及在富氧条件下形成相对致密的氧化膜(如Al2O3,Cr2O3)均能改善其抗燃烧性能。     

激光熔覆纳米SiC增强Ni基合金涂层的组织与高温抗氧化性能

目的揭示添加纳米粉体对激光熔覆涂层高温防护性能的影响。方法以NiCoCrAlY合金粉末为熔覆材料,添加纳米SiC粉体,在GH4037合金表面激光熔覆纳米SiC增强Ni基合金涂层,对熔覆层表面及界面区进行显微组织分析,并进行1070℃下的高温抗氧化性实验。结果加入纳米SiC粉体的激光熔覆涂层组织明显细化,界面区未出现明显缺陷,其高温氧化速率远远低于未加纳米粉体的涂层,氧化膜致密,抗剥落能力显著增强。结论添加适量纳米SiC粉体对Ni基合金激光熔覆层的组织具有明显细化作用,对界面区裂纹的产生有一定的抑制作用,使得熔覆层的高温抗氧化性能显著提高。     

强流脉冲电子束作用下激光熔覆NiCoCrAlYSi涂层组织与性能

利用激光熔覆(Laser cladding, LC)技术在镍基高温合金表层制备NiCoCrAlYSi涂层,随后利用强流脉冲电子束(High current pulsed electron beam,HCPEB)技术对熔覆层表面进行辐照处理。利用X射线衍射仪(X-ray diffraction, XRD)、扫描电子显微镜(Scanning electron microscopy, SEM)等仪器观察HCPEB辐照前后激光熔覆层微观结构演变,并对比分析熔覆层表面显微硬度。结果表明:激光熔覆层主要由γ/γ′相构成,表面存在较多孔隙并具有典型的枝晶偏析现象;HCPEB辐照处理后熔覆缺陷消失,表面发生重熔并形成致密的重熔层,且重熔层厚度随辐照次数的增加而逐渐增加。此外,辐照表面诱发产生交滑移及纳米晶结构。表面显微硬度结果显示,HCPEB辐照处理后熔覆层表面硬度显著高于原始样品硬度。     

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.     

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.     

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.     

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.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.