碳离子注入纯钛表面改性的研究

使用MEVVA强流金属源离子注入机对医用纯钛表面进行C离子注入，注入能量为40和60keV、剂量为（2.0～ 6.0×10^17）ions／cm^2。使用TRIM2003程序模拟计算饱和注入剂量；用XRD和XPS分析注入前后试样表面物相及原子结合状态，并使用SEM观察注入前后磨痕的形貌。研究了C离子注入对医用纯钛腐蚀性能、显微硬度、表面弹性模量和磨损行为的影响。结果表明，C离子注入后医用纯钛表面生成了一层包括TiC强化相和游离态C的表面改性膜，使试样表面显微硬度和弹性模量升高，并使医用纯钛在模拟体液中的耐磨损性能和耐腐蚀性能提高，而磨损程度减轻。     

镁合金表面离子注Ti耐蚀性能的研究

镁合金以其优越的性能在工业上的应用越来越广泛,但是其耐蚀性、耐磨性较差,硬度较低的缺点限制了它的大量使用.利用改进的金属蒸发弧放电离子源(MEVVA)在AZ31镁合金表面注入Ti离子,形成Ti离子注入改性层,以期提高镁合金表面的耐蚀性能.注入能量为45keV,注入剂量为3×1017 cm-2.注入后镁合金表面形成厚度约为450nm的注入层,用SEM、XRD分析了Ti离子注入层的表面形貌和相结构.用CS300P型电化学工作站测试了注入前后镁合金的耐蚀性,结果表明镁合金表面耐蚀性能显著提高.     

Ag离子注入Ti6Al4V合金抗Hank’s溶液腐蚀性能研究

采用注入不同剂量5×1016, 1×1017, 5×1017和9×1017ions/cm2,加速电压30 kV对Ti6Al4V合金进行Ag离子注入表面改性。使用动电位极化曲线研究Ag离子注入前后Ti6Al4V合金抗Hank’s溶液腐蚀性能,利用小角掠射X射线衍射技术研究Ag离子注入前后Ti6Al4V合金表面物相组成,用X射线光电子能谱技术分析离子注入合金表面和腐蚀样品表面元素存在的化合态。结果表明,Ag离子注入提高了合金抗Hank’s溶液腐蚀性能,腐蚀电流密度随Ag离子注入剂量的增加稍有变化。离子注入Ti6Al4V合金表面的氧化物腐蚀阻挡层、离子注入表面合金层和表面生成的Ag和TiAg有利于合金抗Hank’s溶液腐蚀性能的改善     

铬基合金连接体材料在固体氧化物燃料电池中的应用

主要介绍了固体氧化物燃料电池（SOFC）的铬（Cr）基合金连接体材料的发展现状。Cr基合金具有良好的抗氧化性、耐腐蚀性和导电性能等，是目前连接体材料中的研究热点之一。在SOFC阴极环境中，容易形成氧化层，同时由于Cr的扩散和挥发还可能导致阴极中毒，合金中掺杂稀土元素（Y、La、Ce和Zr）可以抑制Cr2O3层的生成。在阳极环境中，Cr基合金的表现优于阴极。与Al2O3、NiO、MgO和TiO2等相比，Cr2O3基氧化层具有较好的综合性能，其耐高温（1100℃）、热膨胀系数（9．6×10^-6K^-1）和YSZ电解质（10．8×10^6K^-1）相近、且具有较好的导电性。目前，Cr基合金的研究重点是氧化物弥散强化（ODS）合金，使用最多的是Cr5FelY2O3，其热膨胀系数为9×10^-6K^-1～10×10^-6K^-1（1000 ℃），抗氧化性能较好。     

钛离子注入对AZ31镁合金表面力学性能及耐蚀性的影响

对AZ31镁合金表面进行了钛离子注入试验,研究了钛离子注入对于镁合金表面改性层的影响。通过XRD、XPS研究了改性层的相结构和元素分布,通过硬度和摩擦磨损试验研究了改性层的力学性能。结果表明,经过钛离子注入之后,改性层中并无新相生成;当注入剂量为2.5×1017ion/cm2时,改性层深度可以达到160 nm,改性层中Ti呈高斯分布,存在形式从外到内为TiO2向Ti过渡。经过钛离子注入之后,镁合金表面硬度大大提高;改性层的摩擦因数并没有降低,但是耐磨性有所提高。随钛离子注入剂量的增加,改性层的耐腐蚀性能呈先上升后下降趋势。     

AZ91镁合金挤压组织和性能研究

对AZ91镁合金铸锭进行（410±5）。C×10h的固溶处理后，在330。C以挤压比为25：1进行了挤压，研究了其组织和性能。结果表明，挤压AZ91镁合金具有较细的晶粒组织，第二相Mg17，A112被破碎，其分布变得弥散，个别呈流线分布；挤压AZ91镁合金比铸造AZ91镁合金的力学性能有较大提高，其屈服强度为210MPa，抗拉强度为355MPa，伸长率为18％。第二相Mg17，Al12对镁合金的性能具有重要影响。     

加工态与铸造态的AZ40镁合金阳极氧化耐蚀性对比

利用正交试验确定了阳极氧化电解液配方,通过比较铸造态和加工态AZ40镁合金金相组织、阳极氧化膜表面形貌、极化曲线,解释加工状态对AZ40镁合金阳极氧化耐蚀性的影响。结果表明,加工态镁合金的腐蚀速率为87．73202mg／（m^2·h）,铸造态镁合金的腐蚀速率为106．37mg／（m^2·h）。由于加工态镁合金的合金元素参与阳极氧化,使膜层结合更致密,表面几乎没有裂纹,对基体更具有保护性。     

钇离子注入锆的动电位极化曲线研究

通过对锆表面进行不同剂量的钇离子注入及对电位极化曲线的测量，分析了钇离子注入对锆电化学行为的影响。结果表明：钇离子注入能明显地提高锆在酸性、中性及碱性环境中的耐腐蚀性能。用X光电子能谱(XPS)分析了离子注入样品表层的成分与价态，进而探讨了钇离子注入表面改性的机理。     

金属离子高温注入原理与工艺研究*

采用离子与固体相互作用理论和辐照增强扩散理论建立了金属离子高温注入的传质模型,利用有效形成热理论建立了金属离子高温注入合成金属间化合物相形成预测模型。采用MEEVA源进行了Al离子高温注入镁合金AZ31表面改性。利用Rutherford背散射和X射线衍射方法分析了注入改性层的成分与相结构,利用动电位阳极极化测量及摩擦磨损试验测定了注入改性镁合金AZ31的耐腐蚀、抗磨损性能。计算的Al离子高温注入镁合金AZ31的成分—深度分布及金属间化合物Al12Mg17形成规律与试验测量结果相符。注入剂量为6×1016ions·cm-2的Al离子高温试样,腐蚀电位和孔蚀击穿电位分别达到-1180mV(SCE)和-480mV(SCE),维钝电流密度较原始镁合金试样的电流密度约降低1个数量级。高温注入镁合金试样的磨痕较窄,磨损量较原始试样减小约20%。Al离子高温注入显著改善了镁合金AZ31的耐腐蚀、抗磨损性能。     

Gd离子注入对固溶态Mg-Nd-Sr-Zr合金生物腐蚀行为的影响

对固溶态Mg-Nd-Sr-Zr合金进行了钆(Gd)离子注入改性处理;采用SRIM 2008软件对Gd离子注入过程进行了模拟分析;采用光学显微镜(OM)观察了镁合金的显微组织,并利用X射线衍射仪(XRD)分析改性层中的物相组成,同时结合X射线光电子能谱(XPS)表征改性层中化学成分与元素价态,采用电化学实验及析氢实验评价了基体镁合金与注入镁合金在模拟体液(SBF)中的生物腐蚀行为。结果表明:Gd离子注入有助于提高固溶态Mg-Nd-Sr-Zr合金在SBF中耐生物腐蚀性能,且当注入剂量为2.5×10~(16)cm~(-2)时,注入镁合金的耐生物腐蚀性能最佳。     

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.