FeCuNbSiB合金的纳米晶化过程研究

应用Ｘ射线衍射分析和穆斯堡尔谱学研究了Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９非晶合金的纳米晶化过程．Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金在５００～６００℃温度范围内分别退火１ｈ，可形成纳米ＤＯ３结构的ＦｅＳｉ相和剩余非晶相。随着退火温度的升高，有更多的ＦｅＳｉ相析出。在５００℃等温退火中ＦｅＣｕＮｂＳｉＢ合金出现二阶段纳米晶化过程。     

非晶态与纳米晶材料的穆斯堡尔谱及高温电阻率的研究

研究了非晶Ｆｅ７８Ｃｒ４Ｓｉ５Ｂ１３及非晶、纳米晶Ｆｅ７３５Ｃｕ１Ｎｂ３Ｓｉ１３５Ｂ９的室温穆斯堡尔谱及高温电阻率和结构驰豫。实验结果表明,两种合金的电性有大的差别,且结构驰豫对非晶、纳米晶Ｆｅ７３５Ｃｕ１Ｎｂ３Ｓｉ１３５Ｂ９的性质有大的影响。     

Fe73.5Cu1Nb3Si13.5B9非晶合金电脉冲处理与等温退火的比较

用直流高密度电脉总和可比等温退火处理Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９非晶合金,并用ＸＲＤ,ＴＥＭ和穆斯堡尔谱方法进行了结构检测。结果表明,在电脉冲作用下,Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｐ９非晶合金在平均温度为４２０℃的条件下发生了纳米晶化,晶化度试样中无Ｆｅ－Ｂ相析出,无ＤＯ３型有序结构;晶化总量达３０．９％的无序ａ－Ｆｅ（Ｓｉ）相的平均尺寸为８～９ｎｍ,按二项式分布计算ａ－Ｆｅ（Ｓ     

Fe_（73．5）Cu_（1．0）Nb_（3．0）Si_（13．5）B_9纳米软

从Ｈｏｐｋｉｎｓｏｎ效应及Ｘ光衍射技术研究了Ｆｅ（７３．５）Ｃｕ（１．０）Ｎｂ（３．０）Ｓｉ（１３．５）Ｂ９纳米软磁合金的居里温度特性。随晶化退火温度Ｔａ的提高，合金中αＦｅ－Ｓｉ纳米晶相的居里温度提高，但低于相同Ｓｉ含量下的常规Ｆｅ－Ｓｉ合金，且与显微组织结构有关，当Ｔａ较低时，合金中非晶相的居里温度与原始非晶合金基本相同。但其Ｈｏｐｅｉｎｓｏｎ峰宽化，Ｔａ＞７８３Ｋ后，其Ｈｏｐｋｉｎｓｏｎ４消失，无法判断居里温度。认为居里温度的上述特性与合金晶粒的小尺寸特性及元素成分分布特性有关。     

铁基软磁纳米微晶中非晶相的穆斯堡尔研究

以穆斯保尔谱分析为主要手段研究了纳米晶（ＦｅａＳｉ）０．９５Ｎｂ０．０５和Ｆｅ６９．５（ＣｕＣｒＶ）９．５Ｓｉ１３Ｂ８、Ｆｅ７３．５Ｃｕ１Ｎｂ８Ｓｉ１３．５Ｂ９合金的非晶相的微结构，介绍了实验方法，并对实验结果进行了探讨。     

铁基软磁纳米微晶中非晶相的穆斯堡尔研究

以穆斯堡尔谱分析为主要手段研究了纳米晶（Ｆｅ３Ｓｉ）０．９５Ｎｂ０．０５和Ｆｅ６９．５（ＣｕＣｒＶ）９．５Ｓｉ１８Ｂ８、Ｆｅ７８．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金的非晶相的微结构，介绍了实验方法，并对实验结果进行了探讨。     

Fe_(76.5-x)Cu_1Nb_xSi_(13.5)B_9的磁致伸缩

Ｆｅ７６．５－ｘＣｕ１ＮｂｘＳｉ１３．５Ｂ９的磁致伸缩样品为Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１６．５Ｂ６和Ｆｅ７６．５－ｘＣｕ１ＮｂｘＳｉ１３．５Ｂ９（ｘ＝２，３和５）。Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１６．５Ｂ６非晶带经５３０℃退火，其他成分样品的退火温度...     

Fe73.5Cu1.0Nb3.0Si13.5B9纳米软磁合金的居里温度特性研究

用Ｈｏｐｋｉｎｓｏｎ效应及Ｘ光衍射技术研究了Ｆｅ７８．５Ｃｕ１．０Ｎｂ３．０ＳＩ１３．５Ｂ９纳米软磁合金的居里温度特性。随晶化退火温度Ｔａ的提高，合金中ａＦｅ－Ｓｉ纳米晶相的居里温度提高，但低于相同Ｓｉ含量下的常规Ｆｅ－Ｓｉ合金，且与显微组织结构有关，当Ｔａ较低时，合金中非晶相的居里温度与原始非晶合金基本相同，但其Ｈｏｐｋｉｎｓｏｎ峰宽化，Ｔａ〉７８３Ｋ后，其中Ｈｏｐｋｉｎｓｏｎ峰消失，无法判断居     

退火对Fe_(66)Cr_8Cu_1Nb_3Si_(13)B_9条带磁弹性的影响

退火对Ｆｅ６６Ｃｒ８Ｃｕ１Ｎｂ３Ｓｉ１３Ｂ９条带磁弹性的影响测定了Ｆｅ６６Ｃｒ８Ｃｕ１Ｎｂ３Ｓｉ１３Ｂ９合金带退火后纳米晶引起的变化来观察磁场与合金杨氏模量的关系。将３ｍｍ宽、２５μｍ厚的Ｆｅ６６Ｃｒ８Ｃｕ１Ｎｂ３Ｓｉ１３Ｂ９非晶合金带材切成５ｃｍ长...     

FeCuNbSiB系纳米微晶的形成及磁性──Ⅰ．纳米微晶的高密度形核

对Ｆｅ７８Ｓｉ１３Ｂ９、Ｆｅ７７Ｃｕ１Ｓｉ１３Ｂ９和Ｆｅ７４Ｃｕ１Ｎｂ３Ｓｕ１３Ｂ９三种非晶合金的晶化过程进行了ＤＴＡ热分析和在位动态电镜观察．在Ｆｅ７７Ｃｕ１３Ｂ９非晶的晶化前期阶段，发现了条状调幅结构，这被认为是Ｃｕ元素Ｆｅ基非晶基体中的Ｓｐｉｎｏｄａｌ分解的产物，富Ｃｕ区还可以作为α－Ｆｅ晶核的产床，导致了高密度形核．     

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。