激光沉积CoCrFeNiSi-(Al,Ti)非等原子比高熵合金涂层腐蚀行为研究

目的 研究Al、Ti元素对激光沉积CoCrFeNi系高熵合金涂层耐蚀性能影响,并对影响程度进行比较。方法 采用激光沉积技术在316L不锈钢表面制备CoCrFeNiSi0.5、CoCrFeNiSi0.5Al0.5、CoCrFeNiSi0.5Ti0.5、CoCrFeNiSi0.5Al0.5Ti0.5等4种成分的高熵合金涂层,并通过X射线衍射仪(XRD)、金相显微镜(OM)、场发射扫描电镜(FESEM)以及电化学工作站等设备对高熵合金涂层凝固组织形貌、微观组织形貌、微区成分分布、耐腐蚀性能等方面进行分析研究。结果 激光沉积CoCrFeNiSi0.5高熵合金涂层物相由单一面心立方(FCC)相构成;CoCrFeNiSi0.5Al0.5高熵合金涂层的主要物相变成体心立方(BCC)相,并形成沿晶界网状分布的Cr3Si相;CoCrFeNiSi0.5Ti0.5高熵合金涂层的主要物相仍为FCC相,但枝晶间区域内形成G相(Ni16Ti6Si7),枝晶内区域形成长条状Cr15Co9Si6相;CoCrFeNiSi0.5Al0.5Ti0.5高熵合金涂层的主要物相为BCC相,枝晶间区域G相含量较CoCrFeNiSi0.5Ti0.5合金涂层有所降低,枝晶内区域形成弥散分布的方形纳米Fe3Al相。激光沉积CoCrFeNiSi-(Al,Ti)非等原子比高熵合金涂层在0.5 mol/L H2SO4溶液中的耐蚀性大小依次为CoCrFeNiSi0.5Ti0.5>CoCrFeNiSi0.5Al0.5Ti0.5>CoCrFeNiSi0.5>CoCrFeNiSi0.5Al0.5。浸蚀后,CoCrFeNiSi0.5高熵合金涂层以均匀腐蚀为主,CoCrFeNiSi0.5Al0.5涂层产生严重的晶间腐蚀,CoCrFeNiSi0.5Ti0.5涂层主要为枝晶间区域的点蚀,CoCrFeNiSi0.5Al0.5Ti0.5涂层枝晶间区域的点蚀程度明显高于CoCrFeNiSi0.5Ti0.5涂层,且枝晶内区域的纳米第二相颗粒发生脱落。结论 在酸性溶液环境中,相较于Al元素,Ti元素可更有效地提升激光沉积CoCrFeNi系高熵合金涂层的耐蚀性能。     

激光熔覆CoCrFeNiSix高熵合金涂层的组织及性能

目的 研究Si含量对CoCrFeNi高熵合金激光熔覆涂层的组织及性能的影响.方法 利用激光熔覆技术在45#钢基材上制备CoCrFeNiSix(x=0.0,0.5,1.0,1.5,2.0)高熵合金涂层,通过扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度计、摩擦磨损试样机,对单道和多道熔覆层的宏观形貌、微观组织、显微硬度及摩擦磨损性能进行观察和测试.结果 高熵合金涂层与基体形成良好的冶金结合,添加适量的Si可以提高熔覆层的表面成形性,随着Si的添加,合金的稀释率先增后减,且润湿角逐渐减小.涂层的微观组织随Si含量的升高由等轴晶变为树枝晶,后又变为等轴晶,晶粒结构尺寸减小,涂层致密度提高.涂层由fcc结构变为bcc结构.涂层的显微硬度随Si含量的增加而增加,在x=2.0时,硬度达到600HV0.5左右,约为基体3倍.磨损方式由粘着磨损变为磨粒磨损,当Si含量最高时,磨损量达到最少,摩擦因数也最低,约为0.49.结论 在CoCrFeNi基高熵合金中添加Si可以降低合金的熔点,提高润湿能力;Si还可以增加涂层的形核率,起到细化晶粒的作用;Si作为添加元素还提高了涂层硬度,改善了涂层的耐磨减摩作用.     

激光熔覆MoFeCrTiWSix多主元合金涂层组织和性能研究

在Q235钢表面激光熔覆制备了MoFeCrTiWSi_x(x=0,0.2,0.4,0.6,0.8,1.0)多主元合金涂层,采用X射线衍射仪(XRD)、扫描电镜(SEM)和硬度计等系统研究了Si对涂层的组织、相结构、显微硬度及高温抗氧化性能的影响。结果表明:激光熔覆MoFeCrTiW多主元合金涂层为简单bcc结构,组织为等轴晶。添加Si后,涂层主体相仍为bcc结构,当x≥0.4后,会有少量金属间化合物生成,合金涂层由先共晶bcc相和共晶组织(bcc相+Cr5Fe50Mo8.9Si5.2Ti20.4相)组成,随着Si量的增加,先共晶相的形态由胞状树枝晶转变为柱状树枝晶和等轴树枝晶,共晶组织逐渐增多。涂层从表面至结合区的混合熵呈高熵-中熵变化。涂层硬度和900℃时的抗氧化性能随着Si含量的增加有所提高,当x=1时,涂层平均硬度及抗氧化性能最高。     

热处理对激光熔覆CoCrFeNiSi2.0高熵合金涂层组织与性能的影响

目的 探究热处理温度对激光熔覆CoCrFeNiSi2.0高熵合金组织、物相、显微硬度及摩擦磨损性能的影响,为研究提高高熵合金性能的工艺流程提供参考。方法 采用激光熔覆技术制备了CoCrFeNiSi2.0高熵合金,利用高温炉加热方法对制得涂层进行不同温度(热处理温度分别为600、800、1 000 ℃)的热处理,30 min分别升温至600、800、1 000 ℃,保温30 min,后随炉冷却至室温。采用显微硬度仪、真空摩擦磨损试验机、Leica DVM6光学显微镜、扫描电镜(SEM)、X射线衍射仪(XRD)等设备对涂层的显微硬度、摩擦磨损性能、显微组织、物相组成进行分析研究。结果 未经热处理原始试样高熵合金涂层物相组成主要为BCC相,同时夹杂少量的(Fe,Mn)2SiO4相,经过不同温度的热处理后,(Fe,Mn)2SiO4逐渐分解,1 000 ℃热处理后完全消失;Cr2Si、Ni4Si相析出且在一定温度范围内随热处理温度上升含量逐渐增加,BCC相衍射峰高度随着热处理温度的增加先升高后降低。结论 热处理温度不同会影响涂层综合性能的改变,热处理温度为800 ℃时合金的综合性能优于原始试样涂层,内部组织较为均匀,Cr2Si、Ni4Si等析出相含量最多且均匀分布在晶界处,涂层显微硬度最高达1 347.4HV0.3,摩擦因数基本稳定在0.19。当热处理温度达到1 000 ℃时,CoCrFeNiSi2.0高熵合金涂层呈单一的BCC相,这势必会对涂层性能产生一定影响。     

冷喷涂辅助感应重熔合成AlCoxCrFeNiCu高熵合金涂层的显微组织和性能

通过冷喷涂辅助感应重熔技术在45钢基体成功制备AlCo_xCrFeNiCu (x=0、0.5、1.0、1.5、2.0，摩尔分数)高熵合金涂层。研究了Co元素含量对冷喷涂辅助合成高熵合金涂层物相、微观组织的影响。结果表明：通过低压冷喷涂辅助感应重熔技术合成的AlCo_xCrFeNiCu高熵合金涂层由fcc+bcc双相混合结构组成，涂层组织为等轴树枝晶+晶间组织，其中枝晶为bcc结构，晶间组织为fcc结构。Co含量的变化会引起AlCo_xCrFeNiCu高熵合金涂层的晶格畸变状态发生变化，当x=1.0时，AlCo₁CrFeNiCu高熵合金涂层的晶格应变最大。Co元素含量增加会促进AlCo_xCrFeNiCu高熵合金涂层中的枝晶数目增加，同时涂层中的树枝晶尺寸也随着Co元素含量增加而增大。涂层中的树枝晶富集Fe、Cr、Co、Ni元素，枝晶间富集Cu元素，Al均匀地分布在整个涂层中。随着Co含量增加，AlCo_xCrFeNiCu高熵合金涂层的硬度先增加后减小；当x=1.0时...     

SiC颗粒对AlCoCrFeNi高熵合金涂层显微组织与力学性能的影响

应用激光熔覆技术制备了Al CoCrFeNi高熵合金涂层,研究了不同Si C添加量对涂层组织、硬度及耐磨性的影响。结果表明:Al CoCrFeNi高熵合金涂层由面心立方结构(FCC)和体心立方结构(BCC)两相组成。添加Si C生成了Cr2Fe14C相,但是抑制了Cr基FCC相的生成。随着Si C含量的增加,熔覆层的缺陷减少且组织形貌发生改变,主要是由晶内BCC、晶间Cr基FCC相和白色析出物组成,其中,白色析出物为Cr2Fe14C相和未熔化的Si C颗粒,且分布在晶间。Si C的加入可以显著提高涂层的硬度及耐磨性,随着Si C含量的增加,涂层的硬度及耐磨性会随之增加。     

激光熔覆CoCrFeNiSix高熵合金涂层的组织与性能

为了探究Si元素含量对CoCrFeNiSi_x(x=0.5,1.0,1.5)高熵合金涂层的组织与性能的影响,采用激光熔覆技术制备高熵合金涂层,通过X射线衍射仪、扫描电子显微镜、能谱仪、显微硬度仪、摩擦磨损试验机、电化学工作站等表征了涂层的物相组成、微观组织以及元素分布、硬度值、耐磨性能和耐腐蚀性能. 研究表明,随着Si元素的含量增加,合金物相由单相面心立方结构转变为面心立方结构、Si元素化合物(σ)相结构,最后形成面心立方结构、体心立方结构和σ相混合结构.涂层的组织主要由柱状晶转变成树枝晶,最后形成胞状晶;同时,涂层的硬度不断提高,当Si含量为1.5时,涂层的平均硬度值达到最高,为619.04 HV0.2,约为基体的2.67倍.涂层的磨损量、摩擦系数随着Si含量的增加而减少,耐磨性能显著提高.涂层在3.5%NaCl溶液中腐蚀性能随着Si含量的增加先增加后降低,当Si含量为1.0时,涂层的耐腐蚀性能最优.     

Mo元素对激光熔覆AlCoCrFeNiMox高熵合金涂层组织性能的影响(英文)

采用激光熔覆的方法制备AlCoCrFeNiMox高熵合金涂层。研究Mo元素含量对涂层微观结构、硬度及耐腐蚀性的影响。结果表明,随着Mo含量的增加,微观组织从富(Al, Ni)的体心立方（bcc）相和富(Mo-Cr-Fe)的σ相,转变为富(Fe, Ni)的bcc相、富(Mo-Cr-Fe)的σ相、富(Al-Fe-Mo)的σ相与少量AlN相。此外,涂层的显微硬度（HV1）从6154.4 MPa增加到10652.6 MPa。随着Mo含量的添加,涂层在3.5%（质量分数）氯化钠溶液中的自腐蚀电位升高,当Mo含量为x=1.0时,涂层的耐腐蚀性能最好。     

激光熔覆CoCrFeNiWx高熵合金涂层的组织及性能

目的 研究W含量对激光熔覆CoCrFeNi高熵合金涂层组织及性能的影响。方法 采用RFL-C1000光纤激光器在45^#钢表面制备CoCrFeNiW_x(x=0、0.2、0.4、0.6、0.8)高熵合金涂层,利用光学显微镜、X射线衍射仪(XRD)、扫描电子显微镜(SEM)、显微硬度计、摩擦磨损试验机等,对熔覆层的宏观形貌、微观组织、显微硬度和摩擦磨损性能进行分析和测试。结果 熔覆层与基材之间的润湿性较好。随着W元素含量的增加,涂层由单一的FCC相转变为FCC相+μ相(Fe₇W₆、Co₇W₆),微观组织由胞状晶转变为树枝晶,晶粒尺寸减小,且在x=0.8时出现了明显的共晶组织和大量μ相沉淀。熔覆层的显微硬度随着W含量的增加而增大,x=0.8时,熔覆层具有最高的显微硬度,达到432.02HV0.3,约为基材硬度的2.1倍,为CoCrFeNi熔覆层硬度的2.2倍。x=0.6时,涂层磨损量最小,仅为CoCrFeNi涂层磨损量的30.85%,平均摩擦因数最低,约为0.31...     

激光熔覆CoCrFeNiTix高熵合金涂层的组织与性能

目的 研究Ti含量对激光熔覆CoCrFeNi高熵合金涂层的组织和性能的影响。方法 利用激光熔覆技术在45钢表面制备CoCrFeNiTi_x（x表示摩尔比值,x为0、0.2、0.4、0.6、0.8）高熵合金熔覆层,并通过Leica DVM6光学显微镜、扫描电镜（SEM）、X射线衍射仪（XRD）、显微硬度计、电化学工作站等设备,对单道和多道熔覆试样的宏观形貌、显微组织、显微硬度、耐腐蚀性能等方面进行分析研究。结果 随着Ti含量的增加,熔覆层的稀释率逐步增大,涂层与基材之间的冶金结合性能变好,但表面的成形质量变差;熔覆层随着Ti含量的增加,由单一的面心立方（FCC）相变为面心立方（FCC）和体心立方（BCC）相混合;在Ti含量的增加过程中,熔覆层的组织由树枝晶变为没有明显方向的等轴晶,且晶粒趋于细化;熔覆层的硬度随着添加元素Ti含量的增加而逐步提高,当x=0.8时硬度值提高至502.39HV0.3;随着Ti含量的增加,熔覆层的腐蚀电位逐渐先向正方向移动,后向负方向移动,腐蚀电流密度先减小后略有增加。结论 在CoCrFeNi合金体系中添加Ti元素,会导致熔覆层的成形质量恶化...     

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.     

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.     

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.