锌浴加镍对热镀锌层组织的影响

利用ＳＥＭ和ＥＰＭＡ研究了含０．２２％Ｓｉ钢板在含镍０．３％以下的几种锌浴中获得的镀层组织。研究结果表明，当锌浴含镍大于０．０７％时，ζ相层变薄而晶粒细化，ζ相柱状晶的晶间和ζ相前沿的η相中现现镍富集，当锌浴中镍含量≥０．２％，在η相中析出Ｚｎ－Ｆｅ－Ｎｉ金属间化合物Г２相的晶粒，文中还根据Ｚｎ－Ｆｅ－Ｎｉ三元相图，探讨了锌浴加镍后层组织变化的原因。     

氯化物电镀Zn—P合金的研究

研究了Ｚｎ－Ｐ合金电镀液组成及工艺条件对镀层含磷量的影响，在最佳工艺参数条件下，可得到磷的质量分数为０．１％左右的Ｚｎ－Ｐ合金镀层。对镀液、镀层性能进行了测试，实验证明经银白色钝化后的Ｚｎ－Ｐ合金镀层的耐蚀性能是纯锌镀层的２倍以上。     

彩色热镀锌工艺及镀层的抗蚀性能

通过镀液成分和工艺试验，筛选出Ｚｎ－Ｍｎ－Ｃｕ和Ｚｎ－Ｔｉ－Ｎｉ两种成分镀液，在一定的浸镀温度和冷却方式下，可以获得表面光滑，色泽均匀的彩虹，金黄，紫，蓝等彩色镀层。盐雾腐蚀试验表明；彩色热镀锌层比常规热镀锌层的耐蚀性能约提高一倍。     

电镀Zn—Fe合金

在碱性锌酸盐电解液的基础上，通过添加适量的二价铁盐及铁络合剂，制备Ｚｎ－Ｆｅ合金镀层。确定了获取Ｚｎ－０．３＾－０．５％Ｆｅ合金镀层的电解液成分及工艺条件，实验结果表明，其耐蚀性优于普通镀锌层。     

55%Al-Zn-1.6%Si合金热浸镀工艺及耐蚀研究

钢管热浸镀５５％Ａｌ－Ｚｎ－１．６％Ｓｉ合金,采用熔剂助镀,浸镀温度６１０￣６２０℃,浸镀时间１５￣２０ｓ,空气速冷至３００℃冷却速度１０℃／ｓ）然后缓冷至室温。合金热浸镀层厚２６￣３２μｍ,金相和Ｘ光衍射分析表明,５５％ＡｌＺｎ－１．６％Ｓｉ合金具有ａ相和β相,腐蚀优先从β相开始。采用中性盐雾试验,浸泡试验对该合金镀层的耐蚀性进行了研究,并将结果与热镀锌,热镀铝进行了对比,铝锌合金镀层的耐蚀性在     

Cu基形状记忆合金的时效

对比研究了时效对亚共析Ｃｕ－１２．０Ａｌ－５．０Ｎｉ－２．０Ｍｎ－１．０Ｔｉ（ｗｔ．－％）合金与Ｃｕ－２０．０Ｚｎ－６．０Ａｌ－微量Ｂ（ｗｔ．－％）合金热稳定性的影响。结果表明，无论在母相状态或马氏体相状态，Ｃｕ－Ａｌ－Ｎｉ合金的时效热稳定性均远优于Ｃｕ－Ｚｎ－Ａｌ合金。Ｃｕ－Ａｌ－Ｎｉ合金母相状态时效伴随着ＤＯ＿３有序畴长大，基体中Ａｌ、Ｎｉ、Ｍｎ等元素贫化，导致Ｍ＿ｓ点升高，马氏体转变量降低。Ｃｕ－Ｚｎ－Ａｌ合金母相状态时效伴随贝氏体转变，引起基体富Ｚｎ富Ａｌ，导致Ｍ＿ｓ点下降，马氏体量降低。Ｃｕ－Ａｌ－Ｎｉ合金高的时效热稳定性可能来源于Ｎｉ对Ａｌ、Ｃｕ等原子扩散的阻碍作用。     

Al－1．6％Si镀层和55％－Al－Zn－1．6％Si合金镀层的缝隙腐蚀

应用电化学技术研究了Ａｌ－１．６％Ｓｉ镀层和５５％Ａｌ－Ｚｎ－１．６％Ｓｉ合金镀层在３％ＮａＣｌ溶液中的缝隙腐蚀历程。试验表明５５％Ａｌ－１．６％Ｓｉ合金镀层耐缝隙腐蚀优于Ａｌ－１．６％Ｓｉ镀层；钝化处理后，两类镀层的缝隙腐蚀孕育期延长，缝内外偶合电流减小，耐缝隙腐蚀性能有较大提高。     

Al—1.6%Si镀层和55%Al—Zn—1.6Si合金镀层的缝隙腐蚀

应用电化学技术研究Ａｌ－１．６％Ｓｉ镀层和５５％Ａｌ－Ｚｎ－１．６Ｓｉ合金镀层在３％ＮａＣｌ溶液中缝隙腐蚀历程，试验表明５５％Ａｌ－１．６％Ｓｉ合金镀层耐缝隙腐蚀优于Ａｌ－１．６％Ｓｉ镀层；钝化处理后，两类支的缝隙腐蚀孕育期延长，缝内外偶合电流减小，耐缝隙腐蚀性能有较大提高。     

锌镍合金电镀技术的研究

研究了采用锌镍合金为阳极进行电镀时,工艺条件对锌镍合金镀层镍含量的影响,寻找出耐蚀性是镀锌层５倍以上Ｚｎ－Ｎｉ（１３％）合金镀层电镀的工艺条件。对镀液进行了连续电镀试验,电镀后镀液中金属离子浓度波动小,采用合金阳极进行电镀可以基本维持金属离子浓度的稳定,还应用多种测试方法,检测了镀层的结合力。     

Ni—P非晶态镀层腐蚀磨损性能的研究

采用脉冲化学镀和化学镀的方法在同样组成的酸性镀液中得到非晶态Ｎｉ－Ｐ合金镀层，测定两种镀层以掺有ＳｉＣ颗粒的柠檬酸腐蚀液中的腐蚀磨损行为，结果表明：脉冲化学镀镀层的耐腐蚀磨损性能优于化学镀镀层；脉冲化学镀镀层有较高的含Ｐ量并且短程有序畴的尺度比化学镀镀层约小０．１ｎｍ。     

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。