高品级柔软耐水砂布的研制

本文研究合成四种树脂粘结剂：柔软耐水布基处理浸渍剂、柔软耐水浆料、柔软耐水酚醛树脂底胶和新型酚醛树脂胶（Td=258℃）。通过在平跑式和悬挂式砂布制造线上,制备高品级柔软耐水砂布,并具有优异的磨削性能。以80^#棕刚玉为例,磨削时间达到2小时,是普通干磨砂布的4倍,磨去金属量（45^#钢）达到42．8克,是普通干磨砂布的6倍。在水中浸泡24小时后,湿磨时间达4小时,是耐水砂纸湿磨时间的8倍,磨去金属量（LY12CZ）41．7克,是耐水砂纸的13倍。     

纳米结构金属陶瓷(n-WC/Co)涂层材料精密磨削的试验研究

本文对纳米结构金属陶瓷（n-WC/Co）涂层材料在金刚石砂轮精密磨削过程中的磨削力进行了较详细的试验研究。对常规结构金属陶瓷(n-WC/Co）和n-WC/Co涂层材料的磨削力作了对比磨削试验,分析了磨削工艺参数如砂轮磨削深度,工件进给速度,金刚石砂轮结合剂类型和磨粒尺寸以及被磨试件材料特性等对磨削力的影响,结合被磨试件表面的扫描电镜（SEM）的观察,分析了n-WC/Co涂层材料磨削的材料去除机理,研究结果表明：在相同磨削条件下,纳米结构陶瓷涂层的磨削力始终高于常规结构陶瓷涂层的磨削力;在其它磨削条件相同的情况下,用金属结合剂砂轮磨削工件所需的磨削力要比树脂结合剂砂轮,陶瓷结合剂砂轮所需的磨削力大些,磨粒尺寸小的砂轮磨削工件所需的总磨削力要比磨粒尺寸在的砂轮所需的磨削力大些,磨削力随砂轮磨削深度,工件进给速度的增加而增大;一般情况下,n-WC/Co涂层材料精密磨削过程的材料去除机理中,占主导方式的是塑性成形的材料去除方式。     

金属/金刚石复合磨料在树脂磨具中的应用

为改善砂轮磨削钢轨的性能,通过热压烧结再固化的方法制备超硬复合磨料树脂磨具试验样条,考察不同种类的复合磨料对样条抗弯强度、抗冲击强度及磨具磨耗比的影响,并用电镜观察磨削后磨具及钢轨对磨件的形貌,表征磨削表面质量.结果显示:超硬磨料与金属结合剂造粒后,抗弯强度、抗冲击强度、磨耗比均得到明显提高,最大分别提高50％、近2倍...     

钢结硬质合金的超精密磨削

本文提出了一种用机械化学磨削实现钢结硬质合金ＧＴ３５超精密磨削的方法，研究了机械化学磨削机理。研制出一种适合于ＧＴ３５超精磨密削用的磨削液，用这种磨削液要吧实现用带有石墨填充的树脂结合剂刚石砂轮进行超精密磨削硬质材料ＧＴ３５。磨削后表面粗糙度Ｒａ，Ｒｚ值低（Ｒａ＝０．０１７μｍ，Ｒｚ＝０．０８５μｍ），表面质量好。本文比较了用不同磨削液冷却时磨削后的表质量，确定了新研制磨削液的磨削效果。同时还研究     

等离子喷涂复合涂层磨损性能及机理

对Ni60、Al2O3 40％TiO2及Ni／Al2O3三种复合涂层与T10钢在不同载荷、不同时间下的干磨摩擦磨损的曲线进行了测试，探讨了磨损机制。研究发现，干磨时Ni60涂层具有较好的耐磨性。涂层的干磨性能与涂层的致密度、孔隙率等密切相关。     

建筑用耐火H型钢的开发

介绍了马鞍山钢铁股份有限公司研制耐火H型钢的成分设计、生产工艺，及其综合性能。此钢的耐火极限裸钢时达27min，涂耐火层后比相同涂层的Q345B提高了43．2％。     

改性环氧树脂基纳米氧化铝超疏水涂层的制备及其耐久性

超疏水材料是一种具有防水、自清洁等功能的仿生材料,具有广阔的应用价值,但表面容易受到环境和机械作用影响而破坏,导致超疏水性能失效。针对此类实际问题,以改性环氧树脂和疏水型纳米氧化铝颗粒为原料,采用分层制备的方式,利用空气喷涂法制备出一种具有良好耐久性的超疏水纳米复合涂层,其接触角可以达到157.57°,滚动角达到2°。在机械耐久性方面,经历30次砂纸摩擦或者45次胶带黏附后,该涂层仍能保持超疏水性能,且与其它商业涂层相比具有更好的机械耐磨性。在化学耐久性方面,该涂层在酸碱溶液中浸泡100 min后仍具有良好的超疏水性能。综上,使用该体系制备的超疏水材料具有良好的耐久性能。     

工艺因素对纳米四方多晶氧化锆浆料固化的影响

水基凝胶流延成型工艺是1种薄片式材料制备新技术，主要是利用陶瓷浆料中有机单体聚合反应形成三维空间的网络结构，将陶瓷颗粒填充于网络骨架中形成具有较高强度的结构均匀的陶瓷坯体。主要研究四方多晶氧化锆薄膜制备过程中，有机单体溶液浓度和pH值对纳米四方多晶氧化锆浆料固化反应的影响。结果表明：随浆料中有机单体浓度的增加，浆料聚合反应速率显著提高，为保证合适的固化时间，有机单体浓度可控制存10％～40％(质量分数)范围内；浆料的PH值对聚合反应速率有显著的影响，随PH值的增大，聚合反应速率降低，合适的pH值范围为9～10；在高于35℃温度范围内，聚合反应速率变化显著，适当的成型温度范围为35℃～45℃；引发剂和催化剂用量增加，反应速率大大提高，为获得较好的成型性能，浆料的引发剂用量应控制在0．15％～0.30％(体积分数，下同)的范围内，催化剂用量在0．20％左右为宜。     

高温松弛软化带辅助激光熔覆制备复合涂层

目的 研究抑制玻璃冲头表面热疲劳裂纹失效和粘着磨损的规律.方法 利用高温松弛软化带辅助激光熔覆制备复合涂层,以Ni60+35％WC(质量分数)粉末作为复合涂层材料,45#钢作为基体材料,316不锈钢网作为高温松弛软化带,研究高温松弛软化带对复合涂层组织结构及其耐磨性能的影响.结果 未加316不锈钢网时,复合涂层表面的磨...     

陶瓷-金属结合剂CBN结块的研制及其性能研究

目前钢轨打磨使用的主要是树脂砂轮,具有材料去除率低、磨削温度高等问题。因此,利用钎焊超硬磨料技术研制新型陶瓷-金属结合剂CBN磨具,并对比陶瓷-金属CBN结块和树脂锆刚玉结块在相同条件下的磨削性能,如材料去除率、磨屑分布和磨削温度等。试验结果表明:相比于树脂锆刚玉结块,陶瓷-金属结合剂CBN结块的材料去除率可提高124%,磨削温度峰值可降低15～50 ℃。      

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.     

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).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

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.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。