Ti—24Al—14Nb—3V—0.5Mo合金的超塑性

研究了温度及应变速率对Ｔｉ－２４Ａｌ－１４Ｎｂ－３Ｖ－０．５Ｍｏ（ａｔ－％）合金超塑性能的影响。试验结果表明，在９８０℃，３．５×１０＾－＾４ｓ＾－＾１的最佳超塑变形条件下，合金显示出较高的超塑性；应变速率敏感性指数ｍ为０．６９，拉伸延伸率Ｅｌ．为８１８％。根据其细小的α２＋β０两相组织和等温拉伸的试验方法，确定合金的超塑性属于细晶组织超塑性。在超塑变形过程中，合金无空洞产生，显微组织发生动态粗化     

循环热处理对高速钢超塑性的影响

此研究了循环热处理工艺对Ｗ６Ｍｏ５Ｃｒ４Ｖ２钢超塑性的影响，结果表明：该网在１０４０℃两次循环淬火是实现其超塑性的最佳热处理工艺：按此工艺进行预处理后，在８１０℃，初始应变速率为５．５６×１０＾－１ｓ＾－１的条件下，该钢的超塑延伸率可达１８７％。     

工业用防锈铝合金板材的超塑性能研究

此主要对工业牌号防锈铝合金板ＬＦ３、ＬＦ２１进行了组织超塑性研究。结果表明，ＬＦ３防锈铝合金，在变形温度为４７０－５１０℃，ελ＝（５．５６－１．１１）×１０＾－４ｓ＾－１的试验条件下可实现超塑性；ＬＦ２１防锈铝合金，在变形温度为５１０－５４０℃、ελ＝（５．５６－８．８３）×１０＾－４ｓ＾－１的试验条件具有超塑性。     

NiAl—Fe金属间化合物塑性的研究

本文研究了金属间化合物ＮｉＡｌ－Ｆｅ的超塑性行为及其机理。结果合金的显微组织由β－ＮＩＡｌ相其体和γ－Ｎｉ无序固溶体相组成,在１１２３－１２５３Ｋ,１．０４×１０＾－４－１．０４×１０＾－２ｓ＾－１拉伸变形时,表现超行为,最大伸长率２３３％超塑性变形试样的断口呈韧性变形试样的断口呈韧性特征,在断裂区没有空洞产生,通过ＳＥＭ分析发现,γ相在变形过程中发生碎化、β相存在动态再结晶。     

7075铝合金防扭臂下接头等温保积成形工艺的研究

根据防扭臂下接头锻件技术条件要求,确定了等温成形工艺为最佳成形工艺方案。中简要介绍了在５＊１０＾１０＾４ＫＮ液压机上实现新工艺时模具结构特必互工艺试验确定了变形温度约为４３０℃,应变速率为１．１＊１０＾－３Ｓ＾－１－７．２＊１０＾３Ｓ＾－１,及较佳的坯料形状,尺寸及润滑剂。本分析了该模锻件产生缺陷的原因和消除缺陷的方法。用新工艺研制的锻件冶金质量冶金ＡＩＲ３３８５、Ｚ９－Ｊ冶－３２４、Ｚ９－Ｊ     

钛制海水冷却器及凝汽器的应用

用普通显微镜和透射电镜研究了Ｔｉ６２５３（Ｔｉ－６Ｍｏ－２５Ｎｂ－３Ａｌ）合金在冷变形，冷变形＋时效，固溶，固溶时效状态的显微组织特征，并测定了该合金在时效状态下的拉伸性能。用于本研究的试样是由厚度１ｍｍ的冷轧材制取，结果表明，在冷变形的试样中观察到位错堆积和胞状结构；冷变形和时效后，细小分散的α相从β晶内析出；在５００℃时效时强度达到１３００ＭＰａ；在固溶处理后，获得了等轴再结晶组织，并出现了穿     

供应态HPb59-1黄铜超塑性压缩的试验研究

对供应状态的HPb59-1黄铜棒材进行了超塑性等温压缩试验,分析了压缩变形过程,研究了试样尺寸对压缩变形过程的影响,确定其最佳超塑压缩变形工艺参数,本试验结果为压缩类成形零件提供了较佳的工艺参数。     

Ni—12Co—5Al合金的超塑变形

采用合适的冶炼及形变热处理工艺获得了具有超细化α－Ｔｉ／Ｔｉ２Ｃｏ双相组织的Ｔｉ－１２Ｃｏ－５Ａｌ合金板材，该合金呈现出优异的高速低温超塑性，在７００℃和３×１０＾－２ｓ＾－１的高应变速率条件下延伸率超过２０００％。微观组织研究表明超塑变形促进了Ｔｉ２Ｃｏ粒子的长大和形状变化，在塑性应变高达１５５０％时试样中仍无孔洞产生，应变硬化和应变速率硬化的共同作用是该合金具有优异超塑性的根本原因。     

汽车上使用钛的潜力与挑战

采用圆柱试样在Ｇｌｅｅｂｌｅ１５００热模拟机上进行高温等温压缩试验，研究了２０９１Ａｌ－Ｌｉ合金在高温塑性变形过程中的稳态流变应力变化规律，结果表明：２０９１合金为正应变速率敏感材料，在温度为３００℃～５００℃和应变速率为１０＾－３ｓ＾－１～１０．０ｓ＾－１变形条件范围内，均存在稳态流变特征；稳态流变阶段，流变应力基本保持不变，稳态流变应力随变形速率的增加而增大，随变形温度的升高而降低，进一步研究     

Al—Li母合金工艺及其应用研究

采用熔盐电解法制取Ａｌ－Ｌｉ母合金，最佳工艺条件为：温度４５０￣５００℃，电解质为ＬｉＣｌ＋ＫＣｌ，其重量比为１：１。采用合金顶熔铸－雾化制粉－热挤压－固熔时效热处理工艺制备高强度铝锂合金，进行性能测试，达到技术指标。     

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。