Ti-Si-N纳米复合薄膜的结构与性能

用工业型脉冲直流等离子体增强化学气相沉积技术,在高速钢(W18Cr4V)表面沉积了Ti-Si-N复合薄膜,研究了Ti-Si-N复合薄膜的微观组织和力学性能.结果显示,薄膜相结构为纳米晶TiN和纳米晶或非晶TiSi2以及非晶相Si3N4;在Si含量为5.0 at%～28.0 at%范围内,薄膜的晶粒尺寸逐渐变大;Ti-Si-N薄膜的显微硬度相对于TiN有明显增加,最高硬度可达40 GPa;高温退火后,Ti-Si-N纳米复合薄膜的显微硬度与晶粒尺寸在800℃高温下仍然保持稳定.     

Ti-Si-N纳米复合超硬薄膜的高温热稳定性

用脉冲直流等离子体增强化学气相沉积（PCVD）方法在高速钢（HSS）基体上制备了Ti—Si-N薄膜，重点从不同温度退火后薄膜相结构、晶粒尺寸和显微硬度的变化等方面，探讨了不同Si含量的Ti-Si-N薄膜的高温热稳定性。结果表明：Ti-Si-N薄膜在900℃以内退火处理后，晶粒尺寸和显微硬度并无明显突变，尤其是Si含量较低时，在800℃，晶粒尺寸和显微硬度几乎没有变化，表明Ti-Si-N薄膜具有非常良好的高温热稳定性，这可能与薄膜相形成在高温下仍为调幅分解有关。     

Ti-Si-N复合膜的微结构及性能研究

为研究Si的加入及含量对薄膜结构和性能的影响,采用磁控反应溅射法制备了一系列不同Si含量的Ti-Si-N复合膜,采用XRD、微力学探针和SEM研究了薄膜的微结构、力学性能和抗氧化性.结果表明:随着Si含量的增加,薄膜晶粒尺寸减小,硬度升高,抗氧化性能提高.Si含量为4%～12%(原子数分数)时,晶粒尺寸随含量增加而急剧下降;当Si含量超过9%时,薄膜硬度处于峰值区;Si含量在7%以上时,薄膜具有较高的抗氧化能力.探讨了Ti-Si-N复合膜硬度升高和抗氧化能力提高的机理.     

反应磁控溅射制备Ti-Si-N薄膜的摩擦磨损性能

用反应磁控溅射方法,在不锈钢表面沉积Ti-Si-N薄膜.用原子力显微镜观察薄膜的表面形貌,Ti-Si-N颗粒尺寸小于0.1 μm,用亚微压入仪测试薄膜硬度,当硅的摩尔分数为9.6%时,薄膜硬度出现最大值47 GPa.球-盘式摩擦磨损结果表明,Ti-Si-N薄膜的耐磨性能明显优于TiN薄膜,加入少量硅元素后,TiN薄膜的抗磨损性能有显著提高,但Ti-Si-N薄膜的室温摩擦系数较高(0.6～0.8),高温下摩擦系数也仅轻微降低(550℃,0.5～0.6).由于Ti-Si-N薄膜的摩擦系数可能与磨损中氧化物生成量的增加有关,常温下Ti-Si-N薄膜的摩擦系数随硅摩尔分数的增加而增大,而高温下Ti-Si-N薄膜的摩擦系数随硅含量上升而降低.     

Mo含量对CrMoAlN薄膜微观结构和摩擦磨损性能的影响

采用非平衡磁控溅射离子镀技术在M2工具钢和单晶Si表面沉积多元CrMoAlN纳米多层薄膜.利用EDS,SEM,XRD,XPS,纳米压痕仪和销盘磨损试验仪研究Mo含量对CrMoAlN薄膜成分、表面和截面形貌、相结构、化学价态、显微硬度和摩擦性能的影响.结果表明,不同Mo含量的CrMoAlN薄膜均为fcc结构,Mo代替了Cr Al N晶格中部分Cr或Al的位置,形成了以fcc-Cr N相为基础的CrMoAlN置换固溶体.随着Mo含量提高,CrMoAlN薄膜表面颗粒尺寸明显减小,截面柱状晶结构逐渐消失.CrMoAlN薄膜的显微硬度和弹性模量随着Mo含量的增加而提高,摩擦系数和磨损率随着Mo含量的提高而降低.Mo含量为19.47%(原子分数)时,显微硬度与弹性模量均达到最大值29.70 GPa和427.53 GPa,摩擦系数和磨损率达到最小值0.271和1.2×10-16m3/(N·m).     

新型Ti-Si-C-N纳米复合超硬薄膜的高温热稳定性

用脉冲直流等离子体辅助化学气相沉积（PCVD）方法在高速钢基体上沉积出新型Ti—Si—C—N超硬薄膜．Ti—Si—C—N薄膜为纳米晶／非品复合结构（nc—Ti（C,N）／a-Si3N4／a-C—C）,当薄膜中Si和C含量较高时,Ti（C,N）转变为TiC,晶粒尺寸减小到2—4nm．薄膜晶粒尺寸和硬度的高温热稳定性均随沉积态薄膜中的原始晶粒尺寸减小而提高,当原始晶粒尺寸在8—10nm之间时,晶粒尺寸和硬度热稳定性可达900℃;当原始晶粒尺寸在2—4nm之间时,晶粒尺寸和硬度热稳定性可达1000℃．薄膜硬度和晶粒尺寸表现出同步的高温热稳定性．分析认为由调幅分解形成的纳米复合结构中的非晶相强烈地抑制晶界滑移与晶粒长大,从而使Ti—Si—C—N薄膜的热稳定性显著提高．     

Si含量对电弧离子镀Ti-Al-Si-N薄膜组织结构和力学性能的影响

利用磁过滤电弧离子镀技术在高速钢基体上制备了不同Si含量的Ti-Al-Si-N薄膜,研究了Si含量对薄膜组织结构以及力学性能的影响.结果表明,Ti-Al-Si-N薄膜主要由晶态TiAlN和非晶态的Si₃N₄组成,随着Si含量的增加,XRD衍射峰强度减弱,晶粒尺寸减小;薄膜的显微组织也由明显的柱状晶转变为致密的纳米晶结构.利用纳米硬度仪对薄膜的硬度和弹性模量进行了分析,结果表明,薄膜的硬度和弹性模量有着相似的变化趋势,随着Si含量的增加,两者都先增加,当Si含量达到一定程度时.它们会逐渐稳定在一定范围内,而后又随Si含量的继续增加呈下降趋势.通过划痕测试对薄膜结合强度进行了分析,结果表明,薄膜与基体的结合强度随Si含量的增加先减小而后增加.     

非平衡磁控溅射离子镀Cu-Nb纳米晶薄膜的微观结构及性能

研究了Nb含量对纳米晶Cu-Nb薄膜微观结构和性能的影响。使用非平衡磁控溅射离子镀技术,在具有(100)晶面的单晶Si基体和玻璃基体上制备不同Nb含量的Cu-Nb纳米晶薄膜,研究Nb含量对纳米晶Cu-Nb薄膜微观结构和性能的影响。将样品置于卧式真空退火炉中进行400 ℃退火,用配备了能量色散X射线光谱仪的场发射扫描电镜、原子力显微镜、X射线衍射仪、纳米压痕仪和四探针电阻率测试仪等分析了退火前后薄膜的微观结构、力学性能与电学性能。结果表明,沉积态Cu-Nb薄膜表面由致密的纳米晶组成,表面粗糙度最高仅为8.54 nm,且无明显的孔洞和裂纹等缺陷。随着Nb含量的增加,薄膜的平均晶粒尺寸下降5 nm,薄膜的硬度也因细晶强化而有所增加,在靶电流为1.3 A时达到最大值4.9 GPa。退火态样品在硬度、弹性模量、平均晶粒尺寸和表面粗糙度方面与沉积态薄膜相比有较小的变化,Cu-Nb薄膜表现出优良的热稳定性。Nb的加入可有效细化晶粒,达到细晶强化的效果,同时Cu-Nb不互溶的特性使得纳米晶薄膜在高温下也可保持较好的热稳定性。Nb靶溅射电流为0.5 A 时薄膜综合性能最佳,此时沉积态Cu-Nb薄膜的电阻率最低,为3.798×10^-7 Ω/m,硬度和弹性模量高达4.6 GPa和139.5 GPa,薄膜厚度为1050 nm,粗糙度R_a为4.70 nm。     

脉冲偏压占空比对TiSiN薄膜结构和性能的影响

采用电弧离子镀方法,通过改变脉冲偏压占空比在M2高速钢和单晶硅片基体上沉积TiSiN薄膜,研究脉冲偏压占空比对TiSiN薄膜形貌结构、元素成分、相结构、纳米硬度和耐蚀性能的影响。脉冲偏压占空比为30%时,TiSiN薄膜表面的大颗粒数目达到最大值832个,占空比为60%时,大颗粒数目减小到451个;脉冲偏压占空比从20%增加到50%,Si试样表面的膜层厚度从390.8 nm增加到2.339 μm;占空比为30%时,Si在薄膜中的含量最高为13.88at%,(220)晶面为择优取向,晶粒尺寸达到最小值5.05 nm,硬度达到28.34 GPa,自腐蚀电流密度达到最小0.5306 μA/cm²;占空比为40%时,(111)晶面为择优取向,Si的含量降低到最小值0.46at%;占空比为50%时,(111)晶面的晶粒尺寸达到13.22 nm,硬度达到最大值42.08 GPa,自腐蚀电位达到最高值-0.324 V(vs SCE)。40%以上的占空比可以减少大颗粒缺陷数量,降低TiSiN薄膜中的Si含量,改变TiSiN薄膜晶粒生长的择优取向,提高薄膜的硬度和耐蚀性能。     

电弧离子镀制备 TiSiN 纳米复合涂层

目的在SiH4气氛下制备Si掺杂的TiSiN纳米复合涂层,为SiH4用于工业化TiSiN涂层生产提供依据。方法采用电弧离子镀技术,在SiH4气氛下,于单晶硅和硬质合金衬底上制备Si掺杂的TiSiN纳米复合涂层,研究SiH4流量对TiSiN涂层化学组分、微观结构、硬度和耐磨性能的影响。结果 SiH4流量对TiSiN纳米复合涂层的微观结构、硬度及摩擦系数的影响明显。随着SiH4流量的增加,TiSiN涂层由柱状晶生长的晶体结构逐渐转变为纳米晶镶嵌于非晶基体的复合结构。Si在涂层中以Si3N4非晶相存在,随着涂层中Si含量逐渐增加,TiN晶粒尺寸逐渐减小,Si3N4起到细化晶粒的作用。在42 m L/min的SiH4流量下,涂层硬度高达4100HV0.025。在对磨材料为硬质合金的条件下,TiSiN涂层摩擦系数小于0.6。结论 SiH4气氛下可以制备出Ti N纳米晶镶嵌于Si3N4非晶相结构的TiSiN纳米复合涂层,涂层的显微硬度较高。SiH4可以作为Si源用于TiSiN纳米复合涂层的工业化生产。     

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.     

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。     

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.     

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 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).     

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.