磷酸介质中甲酚红对冷轧钢的缓蚀作用

    用失重法研究了酸碱指示剂甲酚红对冷轧钢在1.0~10.0 mol/L H3PO4溶液中的缓蚀作用.结果表明：甲酚红对冷轧钢在1.0 mol/L H3PO4溶液中具有良好的缓蚀作用,且在钢表面的吸附符合Temkin吸附等温式,缓蚀率随缓蚀剂浓度的增加而增大,但随磷酸浓度和温度的增加而减小.通过吸附理论和动力学公式求出了相应的吸附热力学及动力学参数,并根据这些参数详细讨论了缓蚀作用机理.     

季铵盐双子表面活性剂的缓蚀性能研究

采用自制的季铵盐双子表面活性剂1,6-二(癸烷基吗啉)己烷(HDMB)作为缓蚀剂,用失重及极化曲线研究了该表面活性剂在1 mol/L盐酸溶液中对Q235钢的缓蚀效果.失重结果表明:在1 mol/L盐酸溶液中HDMB对Q235钢具有良好的缓蚀作用,缓蚀率随缓蚀剂浓度的增加而增大,当浓度达到0.1 mmol/L时,缓蚀率趋于稳定.通过吸附理论、动力学和热力学公式得到相应的参数,并讨论了缓蚀作用机理;极化曲线法表明:HDMB为混合抑制型缓蚀剂.     

稀土离子和香兰素在H_2SO_4溶液中对冷轧钢的缓蚀协同效应

用失重法研究了四种稀土离子(La3+,Ce3+,Ce4+,Nd3+)和香兰素(4-羟基-3-甲氧基-苯甲醛)在1.0 mol/LH2SO4介质中对冷轧钢的缓蚀协同效应。结果表明,香兰素对冷轧钢有中等程度的缓蚀作用,缓蚀率随其浓度的增加而增大;四种稀土离子对冷轧钢的缓蚀作用均较差,最大缓蚀率仅为20%左右。香兰素和稀土Ce4+复配后对冷轧钢产生了明显的缓蚀协同效应,最大缓蚀率可达95%左右;而与La3+,Ce3+和Nd3+复配后均无缓蚀协同效应。     

紫茎泽兰叶提取物作为冷轧钢在HCl中的缓蚀剂

用失重法和动电位极化曲线研究了紫茎泽兰(Eupatorium adenophora Spreng.)叶提取物(EASLE)在1.0mol/L HCl溶液中对冷轧钢的缓蚀行为。结果表明:EASLE在HCl溶液中对钢具有良好的缓蚀作用,缓蚀率随缓蚀剂浓度的增加而增大,但随温度的升高而降低。EASLE在钢表面的吸附符合Langmuir吸附等温式,得出了吸附热力学参数(吸附焓ΔH0,吸附Gibbs自由能ΔG0,吸附熵ΔS0),并据此探讨了EASLE的吸附行为。动电位极化曲线表明,EASLE为混合抑制型缓蚀剂。     

芳香醛在磷酸中对冷轧钢的缓蚀作用

用失重法和动电位极化曲线法研究了在3.0 mol/L H3PO4中三种芳香醛原儿茶醛(3,4-二羟基苯甲醛)、香兰醛(4-羟基-3-甲氧基-苯甲醛)和肉桂醛(3-苯基-丙烯醛)对冷轧钢的缓蚀作用.结果表明:三种芳香醛对钢的缓蚀率随芳香醛的浓度增加而增大,为阴极抑制型缓蚀剂,且在钢表面的吸附符合Langmuir吸附校正模型;三种芳香醛的缓蚀率排序为:肉桂醛>香兰醛>原儿茶醛.     

L-苯丙氨酸对Q235钢在硫酸中的缓蚀作用

采用电化学方法,研究了L-苯丙氨酸对Q235钢在0.5mol/L H2SO4溶液中的缓蚀作用及缓蚀机理,分析了其缓蚀剂类型。结果表明:L-苯丙氨酸的缓蚀效率随浓度的增加而增大,而且随着温度的升高,Q235钢表面单个活性位点上吸附的缓蚀剂分子数量增加,缓蚀效率也增大;L-苯丙氨酸属于混合抑制型缓蚀剂,作用机理为几何覆盖效应,其在Q235钢表面的吸附为单分子吸附,且吸附规律符合El-Awady动力学模型。     

糖基季铵盐双子表面活性剂的缓蚀性能

由葡萄糖和十四烷基二甲基叔胺合成的糖基季铵盐双子表面活性剂(C14-GDQ)作为缓蚀剂,用静态失重法研究了该表面活性剂在1 mol/L盐酸溶液中对Q235钢的缓蚀作用。结果表明,在1 mol/L盐酸溶液中C14-GDQ对Q235钢具有良好的缓蚀作用,缓蚀率随缓蚀剂浓度的增加而增大,当缓蚀剂质量浓度达到0.1mmol/L时缓蚀率趋于稳定。通过吸附理论、动力学和热力学公式得到相应的参数,并讨论了缓蚀作用机理。     

竹叶提取物对LST12钢在NH_4Cl溶液中的缓蚀作用

用失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了竹叶提取物(DLMLE)在0.5mol/L NH_4Cl溶液中对冷轧钢的缓蚀作用。结果表明:DLMLE在NH_4Cl溶液中对冷轧钢具有良好的缓蚀作用,缓蚀率随缓蚀剂质量浓度的增加而增大,最大缓蚀率可达85.9%;DLMLE在冷轧钢表面的吸附符合Langmuir吸附等温式,吸附过程为物理吸附和化学吸附的混合吸附过程;DLMLE为混合抑制型缓蚀剂,EIS谱呈单一压扁的半圆容抗弧,电荷转移电阻随缓蚀剂质量浓度的增加而增大。     

红四氮唑对冷轧钢在磷酸溶液中的缓蚀性能

用失重法、动电位极化曲线和原子力显微镜（AFM）研究了红四氮唑对冷轧钢在1.0 mol/L~10.0 mol/L H₃PO₄溶液中的缓蚀作用。结果表明：红四氮唑对冷轧钢具有中等程度的缓蚀作用,为混合抑制型缓蚀剂,且在钢表面的吸附符合Freundlich吸附模型;通过吸附热力学和腐蚀动力学公式分别求出了相应的吸附热力学参数和动力学参数,并根据这些参数详细讨论了缓蚀作用机理;AFM测试结果表明添加红四氮唑后钢表面较为平整,粗糙度降低。     

麻竹竹叶提取物在酸性介质中对冷轧钢的缓蚀作用

从麻竹(Dendrocalmus latifcorus Munro)竹叶中提取出的固体物质,可以作为一种环境友好型植物缓蚀剂。用失重法研究了麻竹竹叶提取物在1.0 mol/L HCl1、.0 mol/L H2SO4和1.0 mol/L H3PO4三种酸性溶液中对冷轧钢的缓蚀作用。结果表明:麻竹竹叶提取物对冷轧钢的缓蚀率随缓蚀剂浓度的增加而增大,当其浓度为200 mg/L时,三种酸溶液中的缓蚀效率可分别达到92.3%(HCl)、88.9%(H2SO4)、75.8%(H3PO4)。且在钢表面的吸附符合校正的Langmuir吸附等温式。并根据试验结果探讨了缓蚀机理。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.