无气喷涂MoS2/Cu/C复合涂层对海上管柱螺纹抗粘扣性能的影响

目的 采用无污染的无气喷涂表面处理工艺,制备MoS₂/Cu/C复合涂层,提高海上管柱螺纹抗粘扣性能。方法 在MoS₂/C涂层中掺杂纳米级Cu粉末,采用无气喷涂+高温固化+喷砂处理工艺,制备MoS₂/Cu/C复合涂层。通过显微组织、硬度测定和摩擦试验,分别评价MoS₂/Cu/C复合涂层的微观组织、显微硬度和摩擦系数,并通过扫描电子显微镜对MoS₂/Cu/C复合涂层进行形貌分析。最后,在实物试样上进行上卸扣试验,测试其抗粘扣性能。结果 无气喷涂+高温固化过程中,半熔融粉末经过多次叠加,沉积形成致密的结构,未见明显孔隙。对MoS₂/Cu/C复合涂层进行喷砂预处理,可明显提高涂层的均匀度,增加涂层的粘结强度。涂层与基体之间呈锯齿形紧密机械结合,喷砂无气喷涂前后,基体硬度未发生改变,未对金属基体造成不利影响。MoS₂/Cu/C复合涂层在螺纹表面结合形成光滑的保护膜,螺纹表面摩擦系数降低,上扣扭矩降低幅度为19%～23%。结论 在Mo S2/C涂...     

MoS2-Ti自润滑复合薄膜的高温摩擦学性能研究

目的探究Ti含量对MoS₂-Ti复合薄膜高温摩擦学性能的影响,制备高温摩擦性能良好的MoS₂-Ti复合薄膜。方法采用射频和直流双靶共溅射技术沉积了不同Ti含量的MoS₂-Ti复合薄膜,研究了Ti含量对MoS₂-Ti薄膜微观结构和力学性能的影响,进一步探究了MoS₂-Ti复合薄膜在大气环境下的高温摩擦学性能。采用能谱仪(EDS)、X射线衍射仪(XRD)和扫描电子显微镜(SEM),对薄膜的成分、晶相结构及微观形貌进行分析。利用显微维氏硬度计测试薄膜的力学性能,通过UMT-TriboLab摩擦磨损试验机评价薄膜的摩擦磨损性能。此外,采用SEM、拉曼光谱仪(Raman)和X射线光电子能谱仪(XPS),对薄膜的磨痕形貌及对偶球转移膜的成分进行分析。结果Ti掺杂促进了MoS₂薄膜以(002)晶面择优取向生长,且提高了薄膜的致密度,薄膜硬度从70HV提升到350HV。MoS₂-Ti复合薄膜在高温环境下的摩擦性能,随Ti含量的增加呈先上升后下降的趋势,其中Ti原子数分数为6.81%的MoS₂-Ti复合薄膜具有较低的摩擦因数和磨损率。通过对转移膜的成分进行分析,发现处于300℃高温环境下,Ti原子数分数为13.51%的MoS₂-Ti复合薄膜由于在摩擦过程中生成的氧化物较多,其耐磨性能开始下降。结论Ti含量对MoS₂-Ti复合薄膜的高温摩擦学性能有明显的影响,掺杂适量Ti能显著提高MoS₂薄膜在大气环境下的高温摩擦学性能。     

掺杂元素Ti对WS2薄膜结构和摩擦学性能的影响

目的 提高单一成分WS₂薄膜的力学和摩擦学性能。方法 采用多靶磁控溅射方法制备不同Ti含量的WS₂–Ti复合薄膜。利用X射线能谱仪（EDS）、拉曼光谱仪（Raman）、X射线光电子能谱仪（XPS）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）、纳米压痕仪,对薄膜的成分、化学态、晶体结构、形貌以及力学性能进行表征,并利用球–盘摩擦试验机检测该系列薄膜在大气和真空环境下的摩擦学性能。结果 掺杂元素Ti显著改善WS₂薄膜的微观结构、力学性能和摩擦学性能。随着Ti含量的增加,WS₂薄膜的结晶度下降,致密度增加,其硬度和杨氏模量分别从0.25 GPa和16.60 GPa增加到3.52 GPa和59.00 GPa。Ti原子数分数为7.17%时,复合薄膜的磨损率在真空和大气环境下分别低至0.10×10^-15 m³/（N·m）和2.66×10^-15m³/（N·m）。结论 在真空摩擦试验中,WS₂基薄膜的...     

Ti6Al4V合金激光熔覆Ni基自润滑涂层的组织和性能

利用光纤激光器在Ti6Al4V合金基体表面制备了Ni25为基体和Ni包MoS₂为润滑剂的Ni基自润滑涂层,通过FESEM、XRD、硬度测试仪和摩擦磨损试验机研究了熔覆层的显微组织、物相组成和摩擦性能。结果表明,熔覆层表面主要以“花瓣”状组织以及少量的树枝晶组成,界面处的组织主要是以树枝晶为主,还有少量的等轴晶粒。熔覆层中形成了NiTi、NiTi₂等金属化合物以及其它一些化合物,这些强化相的形成有效地提高了熔覆层的表面硬度,由基体的180~200 HV0.3提高到了表层的430~530 HV0.3。同时随着Ni包MoS₂含量增加,表层的硬度会有所下降。此外,当MoS₂加入量为5%和10%时摩擦因数较大,加入量达到15%时摩擦因数有所降低,同时,熔覆层的磨损率也从5%时的7.49×10^-7 mm³·N^-1·m^-1降低到15%时的3.29×10^-7 mm³·N^-1·m^-1。     

纳米压痕法研究n-Al2O3/Ni复合镀层的微观力学性能

应用纳米压痕法测试钢基体上n-Al2O3/Ni复合电刷镀层的硬度、弹性模量以及抗蠕变等性能,研究了镀层力学性能随镀层厚度的分布规律.结果表明,在整个厚度范围内复合镀层的力学性能一致,无明显的梯度分布.镀层内部存在缺陷的区域硬度和弹性模量降低,特别是枝状晶内部的组织疏松引起较大区域的性能降低,而枝状晶交界处形成的空隙对周围镀层性能没有明显影响.复合镀层的平均硬度和弹性模量分别为6.34GPa和161GPa,硬度为钢基体的2.4倍,复合镀层的压痕蠕变与传统单轴压缩蠕变过程相似,稳态蠕变速率约0.1nm/s.     

不同气体流量比对Cu/a-C∶H复合薄膜结构及摩擦学性能的影响

采用磁控溅射技术结合等离子体气相沉积技术,通过调节CH₄与Ar的气体流量比例,获得了不同Cu含量的Cu/a-C∶H复合薄膜。采用XPS、Raman等表征方法分析了不同气体流量比对Cu在复合薄膜中的存在形式及薄膜结构的影响,利用纳米压痕仪测量了复合薄膜的硬度与弹性模量,采用往复式摩擦磨损试验机、白光干涉仪、FESEM等分析了复合薄膜在空气中的摩擦学性能及相关机理。结果表明:随着CH₄在混合气体中所占比例增加,复合薄膜中sp²C含量升高,Cu含量降低,Cu晶粒的尺寸变小,复合薄膜的硬度逐渐升高,韧性降低。CH₄气体流量比为60%、Cu含量为 6.68at%的复合薄膜具有较高的硬度、良好的韧性以及在空气中最低的摩擦因数(0.091)与磨损率(1.77×10^-6 mm³·N^-1·m^-1),这与复合薄膜中sp²C含量及Cu纳米粒子的尺寸和含量有关。     

低能Si离子注入对TiN硬质薄膜性能的影响

采用低能MEVVA离子源技术对由磁过滤阴极真空弧沉积的TiN硬质膜进行了Si离子注入.采用场发射扫描电子显微镜、纳米硬度测试等方法,研究了基体离子注入剂量对薄膜性能的影响.结果表明,Si离子注入能在薄膜表面形成均匀细小的纳米颗粒.使基体及薄膜硬度从33 GPa提高到56 GPa,弹性模量从360 GPa提高到750 GPa.对薄膜进行多(4)次注入,硬度和弹性模量的提高并不显著,但对基体离子注入充分,薄膜的整体硬度和吸收塑性变形能的能力均有显著提高.     

MoS2薄膜摩擦因数和磨损量的数学模型

目的 构建MoS₂薄膜的摩擦因数模型和磨损模型,预测其磨损体积。方法 通过球-盘摩擦磨损实验,研究法向载荷和滑动速度对MoS₂薄膜摩擦因数的影响规律,其中最大接触压强范围为441.08～1393.82MPa,滑动速度为0.05～0.628m/s。利用场发射扫描电子显微镜（SEM）和白光共聚焦显微镜分析MoS₂薄膜的磨损形貌。结果 基于赫兹接触理论,建立了MoS₂薄膜摩擦因数与法向载荷和滑动速度的数学模型。预测结果与实测结果之间的最大相对误差为12.02%,其余预测结果的相对误差均小于10%。从摩擦耗散能的角度,研究发现MoS₂薄膜的磨损体积与摩擦耗能之间呈显著的线性关系,结合新的摩擦因数模型,提出了MoS₂薄膜的磨损模型。此磨损模型是法向载荷、滑动速度和摩擦时间的函数关系式,其相对误差绝对值的平均值为10.81%。与传统Archard模型的结果进行比较发现,新的磨损模型的相对误差较小。通过分析MoS₂薄膜的磨损机理,探讨了磨损模型产生...     

95%Ar+5%H2气氛中退火对M/MoS2(M=Ti、Al、Mo和Ag)薄膜形貌、结构和电学性能的影响

采用射频(RF)磁控溅射在硅基片上连续逐层沉积制备了M/MoS₂(M=Ti、Al、Mo和Ag)纳米薄膜，随后对其在95%Ar+5%H₂混合气氛中进行了500℃的退火处理。采用原子力显微镜(AFM)、扫描电镜(SEM)、拉曼光谱(Raman)、X射线光电子能谱(XPS)和两探针等研究了退火处理及不同金属膜基底对MoS₂薄膜表面形貌、结构和金半接触电性能的影响。结果表明：所制备的纳米膜均匀且连续，界面紧密且清洁；95%Ar+5%H₂混合气氛中退火处理能强烈影响顶部MoS₂层的形貌并可有效去除MoS₂中的杂质氧，改善其结晶性、稳定性和结构完整性；拉曼光谱结果显示在4种金属基底上的MoS₂薄膜均为块状结构，其中Ag和Mo基底上的MoS₂薄膜结晶性相对较好，Ag基底上MoS₂薄膜出现了呈片层与颗粒的混合形态；对比实验数据和综合性能得出Mo作为MoS₂的组成元素，与MoS_...     

磁控溅射ZrAlCuN薄膜的微观组织与力学性能

采用磁控溅射技术制备不同原子比的ZrAlCuN薄膜。采用场发射扫描电镜(FESEM)观察截面形貌,高分辨透射电镜分析微观组织结构,纳米压入法测定薄膜的硬度,压入法(维氏压头)测定薄膜的韧性。结果表明:Zr0.36Al0.15Cu0.01N0.48薄膜截面呈纳米尺度柱状晶,沿沉积方向生长,仅存在[111]、[200]、[220]、[311]取向的5~10nm ZrN晶粒,未发现AlN及Cu独立相,硬度约41.7GPa(载荷10mN),弹性模量约257.8GPa。Zr0.29Al0.24Cu0.08N0.39薄膜呈纳米尺度柱状晶,存在10~20nm ZrN纳米晶以及Cu[111]纳米晶,硬度约27GPa(载荷10mN),弹性模量约225.8GPa。由于前者具备较高的硬度/弹性模量比,从而表现出较好的韧性。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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。     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.