不同冷却速度下球墨铸铁的基体组织

采用Ｇｌｅｅｂｌｅ１５０００试验机研究了不同冷却速度下球墨铸铁的基体组织,研究结果表明,对于成分（％）为３．６２℃,３．０３Ｓｉ,２．５１Ｍｎ,０．０２Ｓ,０．０３Ｐ的球墨铸铁,冷却速度小于０．０２５℃／ｓ,其基体组织为铁素体和球光体;当冷却速度为０．２－０．５℃／ｓ时,基体组织主要为珠光体;当冷却速度为１－６℃／ｓ时,基体组织为贝氏体和马氏体;当冷却速度提高１５℃／ｓ时,基体组织全部为马氏体组织     

86CrMoV7钢热变形奥氏体CCT图

采用膨胀法测定了８６ＣｒＭｏＶ７钢经Ｔ＝９００℃，ζ＝１ｓ＾－１，ε＝０．４热变形后的连续冷却变曲线。结果表明，试验用钢在连续冷却转变过程中，只存在珠光体，马氏体转变，不发生珠光体转变的临办冷却速度为３．１℃／ｓ，Ｍｓ点为１５０℃，组织分析发现，未溶碳化物可成为珠光体转变的核心，促进珠光体转变。     

冷却速度对Fv520（B）多马氏体组织的影响

利用膨胀法、金相、ＸＲＤ法研究了冷地ＦＶ５２０（Ｂ）钢Ｍｓ点及其组织的影响。结果表明，ＦＶ５２０（Ｂ）钢具有良好的淬透性，其Ｍｓ点为１５５℃，冷和速度降低，Ｍｓ点略有升高。在冷却速度为１７．５℃／ｓ～０．０３℃／ｓ的范围内，均得到马氏体组织，冷却速度对马氏体组织状态影响不大。     

碳和锰元素对Mn-Si双相钢连续冷却转变的影响

探讨了碳（由０．０６６％增至０．１３％）,锰（由２．０１％增至３．０１％）含量对ＭｎＳｉ双相钢９６０℃奥氏体化后连续冷却转变的影响。结果表明：碳的增高明显推迟铁素体、珠光体、贝氏体和马氏体转变;当锰含量增至３．０１％时,在１０℃／ｍｉｎ慢速冷却条件下均不发生铁素体和珠光体转变。     

碳和锰元素对Mn—Si双相钢连续冷却转变的意识

探讨了碳（由０．０６６％增至０．１３％），锰（由２．０１％增至３．０１％）含量对Ｍｎ－Ｓｉ双相钢９６０℃奥氏体化后连续冷却转变的影响。结果表明：碳的增高明显推迟铁素体、贝氏体和马氏体转变；当锰含量增至３．０１％时，在１０Ｃ／ｍｉｎ慢速冷却条件下均不发生铁素体和珠光体转变。     

3Cr-1Mo-1/4V钢的CCT图

采用膨胀法测定了大型临氢容器用３Ｃｒ－１Ｍｏ－１／４Ｖ钢的ＣＣＴ图,结果表明：该钢具有高的淬透性。获得完全马氏体的临界冷却速度为１０℃／ｓ;不发生先共析铁素体转变的临界冷却速度为０．０１２℃／ｓ。组织分析表明,在３￣０．０２℃／ｓ的冷却速度范围内均获得粒状贝氏体组织。     

钢轨耐疲劳损伤性能的研究

日本铁路列车向高速度、重负荷和车次过密方向发展，一般轨难以满足要求，提出使用耐转动疲劳损伤性能良好的钢轨。日本ＮＫＫ公司等单位对常用的珠光体钢轨和贝氏体钢轨耐疲劳性能进行研究。珠光体钢轨成分（％），Ｃ：０．６５～０．７７，Ｓｉ：０．２５～０．７２，Ｍｎ：０．８０～１．２３，Ｃｒ：０～０．２５％，Ｖ：０～０．０５；贝氏体钢轨成分（％），Ｃ：０．１９～０．５５，Ｓｉ：０．１８～０．３３，Ｍｎ：１．４０～１．５０，Ｃｒ：０～２．０％、Ｍｏ：０～１．９５，Ｖ：０～０．０７。以此２种成分在１２５０℃下轧制…     

贝氏体型非调质钢过冷奥氏体的连续冷却转变

研究了一种 Ｍｎ Ｂ系低碳贝氏体型非调质钢过冷奥氏体的连续冷却转变,获得了试验用钢过冷奥氏体的连续冷却转变曲线。试验结果表明,本试验用钢过冷奥氏体不发生先共析铁素体析出的临界冷却速度为０．７℃／ｓ;冷却速度在１～４．５℃／ｓ 范围内可得到全部贝氏体组织;当冷速大于４．５℃／ｓ 时,不再有贝氏体生成,室温组织为马氏体和残余奥氏体。     

溴化碲分光光度法测定钛铝合金中微量碲

溴化碲分光光度法应用于钛铝合金中微量碲的测定，取得了良好的效果。干扰试验表明，在所选定条件下，Ｚｎ，Ｍｎ，Ｍｇ，Ｐｂ，Ｍｏ，Ａｓ，Ｙ，Ｓｎ，Ｎｂ，Ｓｂ，Ｐ，Ｃｏ，Ｎｉ，Ｃａ，Ｓｉ，Ｃｄ，Ｂｉ，Ｃｅ，Ｚｒ，Ｗ，Ｖ各１ｍｇ，Ｃｕ，Ｃｒ各０．１ｍｇＦｅ为０．２ｍｇ，对１００μｇＴｅ的测定基本无干扰，ＴｉＡｌ基体的轻微干扰可以用同量的ＴｉＡｌ作参比而消除。分别对含Ｔｅ０．１００％和０．０２０％的两组合成试     

30Si2MnCrMoVA钢断裂韧度研究

本文研究了几种冶金因素对３０Ｓｉ２ＭｎＣｒＭｏＶＡ钢断裂韧度的影响。试验结果表明，通过真空感庆炉和真空自耗炉两次真空冶炼工艺，提高了钢的纯净度，明显改善钢的断裂韧度，采用９３０℃奥氏体化，锭子油淬火和３００℃回火，获得高位错密度板条马氏体组织。钢的抗张强度和断裂韧度达到最佳配合。适当调整钢的含碳量在０．２７－０．３２％范围内，抗张强度为１７２０－１７９５ＭＰａ，断裂韧度达到９２．６－１０３．１ＭＰ     

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。