CuZnAl(RE)形状记忆合金干滑动磨损性能研究

采用不同热处理工艺、不同栽荷、不同磨损时间，对2种成分（不同相变点）的CuZnAl（RE）形状记忆合金进行了干滑动磨损试验，与锡青铜和铝铁青铜做了对比试验，用电子扫描显微镜和x射线衍射仪对磨损表面及合金相组成进行了观察和检测。试验结果表明，晶粒细化与锻打能提高合金的耐磨性，合金的M相比β相耐磨，两级时效处理的合金耐磨性能优于分级淬火处理的合金，CuZnAl（RE）形状记忆合金的耐磨性优于锡青铜和铝铁青铜；CuZnAl（RE）形状记忆合金耐磨的原因主要在于，形状记忆效应和超弹性、应力诱发马氏体相变、晶粒细化等。     

CuZnAl形状记忆合金磨损性能试验研究

对CuZnAl形状记忆合金采用不同热处理工艺处理后,在不同载荷、不同磨损时间、不同摩擦副条件下进行了干磨损和油润滑动磨损试验。同时与锡青铜和铝铁青铜进行了对比试验,并用电子扫描显微镜对磨损表面和磨屑进行了观察。结果表明:CuZnAl形状记忆合金在干磨损条件下,两级时效处理的合金耐磨性能优于分级淬火处理的合金,而在油润滑动磨损条件下,分级淬火处理的合金耐磨性能优于两级时效处理的合金。CuZnAl形状记忆合金的耐磨性能优于锡青铜和铝铁青铜。用CuZnAl形状记忆合金组成的摩擦副,其耐磨性优于用45#钢与形状记忆合金组成的摩擦副。     

相变温度对CuZnAl形状记忆合金干磨损性能的影响

研究了相变温度对复合细化后的CuZnAl形状记忆合金干滑动摩损性能的影响,结果表明：同样的热处理工艺,在摩擦副温升不大时高温相变合金比低温相变合金耐磨,摩擦副温升较大时,低温相变合金耐磨性优于高温相变合金。合金的磨损失重机制为粘着磨损、剥离磨损和犁削磨损。     

热处理工艺对CuZnAl形状记忆合金组织与耐磨性能的影响

研究了热处理工艺对复合油化后的CuZnAl形状记忆合金组织与耐磨性能的影响,结果表明,不同热处理工艺处理的CuZnAl形状记忆合金的室温组织不一样,不同的组织对合金的磨损性能有影响。轻载荷下,合金的M相比β相耐磨,两组时效处理的合金耐磨性能优于分级淬火处理的合金;在较重载荷（294N)下,150摄氏度分级淬火处理的合金耐磨性最优。     

铸造铜合金与不锈钢干摩擦磨损性能的研究

采用M-2000型摩擦磨损试验机研究了铜合金的干摩擦磨损性能,在干摩擦条件下测量了不同成分铜合金与不锈钢组成的摩擦副的磨损量和摩擦系数,用扫描电镜观察其磨损表面,并对其磨损机理进行了探讨分析。结果表明,铜合金的磨损机制主要以粘着磨损和磨粒磨损为主,在所研究的三种铜合金中,ZQAl9-4无锡青铜具有良好的耐磨性及干摩擦性能。     

Cu基形状记忆合金干滑动磨损研究

对Cu基形状记忆合金CuZnAl进行了干滑动磨损,采用扫描电镜观察磨损表面及磨屑.结果表明,CuZnAl合金的磨损过程受塑性变形控制,粘着与转移磨损和剥离磨损是材料失重的两种主要机制.电镜薄膜拉伸时显微裂纹尖端发生了应力诱发马氏体相变.用显微裂纹钝化作用的马氏体择优取向机制和应力诱发马氏体相变机制阐述了这种软基体高变形能力材料的耐磨本质。     

高铝锌基铸造合金耐磨性能探讨

作者研究了ZZnAl27Cu2和ZZnAl12Cul锌合金的耐磨性能.并与ZQSn6-6-3和ZQAl9-4铜合金作了对比试验.对该合金的耐磨机理与添加微量元素对其耐磨性能的影响进行了探讨和分析.试验数据表明,高铝锌合金的摩擦系数与磨损量略低于或相当于青铜,加入微量元素可进一步提高其耐磨性能.认为该合金是一种良好的耐磨材料,可替代部分青铜制作耐磨件,在工业生产中有很大的实用价值和潜力.     

CuZnAl形状记忆合金热机械循环滞回曲线与振动衰减特性研究

运用电子万能拉伸试验机、动态数据采集分析仪,测试了CuZnAl形状记忆合金的力-变形滞回曲线和安装有CuZnAl形状记忆合金耗能器框架结构的减振性能.借助透射电镜、X射线衍射仪,分析了CuZnAl形状记忆合金热机械循环过程中显微组织的变化.比较了不同热处理方式、不同相变点的CuZnAl形状记忆合金热机械循环后的滞回曲线面积及减振性能.试验结果表明:CuZnAl形状记忆合金用于框架结构的被动振动控制具有较好的减振性能,同时明显降低框架结构的振动频率.马氏体CuZnAl形状记忆合金耗能器具有较大的耗能能力,热机械循环数十次以后滞回面积亦大幅度减小,但相变点高的CuZnAl形状记忆合金的滞回面积减小幅度较小.     

固溶时效深冷处理对ZQAl10-3-1.5合金摩擦磨损性能的影响

对ZQAl10-3-1.5合金进行不同的处理工艺处理,利用光学显微镜、万能材料试验机、全自动显微硬度仪以及扫描电镜分析了合金处理前后的显微组织、力学性能、磨损量以及磨损形貌的变化。结果表明:铸态合金以黏着磨损为主,T6态合金以黏着磨损和重度磨粒磨损为主,T6态合金经过深冷处理后则主要以磨粒磨损为主;T6态合金进行适当的深冷处理可以细化晶粒,降低空位密度,增大位错密度,增强致密性,显著提高合金的硬度和耐磨性,但是随着深冷时间的延长,ZQAl10-3-1.5合金的磨损量和平均摩擦系数会出现先降低后增加的趋势。     

化学成分及热处理对镀镍层耐磨性的影响

试验研究了化学成分与热处理对化学镀镍层耐磨性的影响。磷含量的改变使镀镍层的组织结构变化,低磷固溶体4.0％P合金的磨损体积低于非晶态9.O％P合金,经过175~600℃热处理,耐磨性具有不同的变化;镀镍层中复合硬质相SiC,耐磨性优于镍磷合金层,并随热处理改变。     

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.