喷丸残余应力裂纹柔度法与X射线法对比研究

用裂纹柔度法对45钢调质喷丸试样的残余应力大小及分布进行了测量,并将其测试结果与结合电解抛光技术的X射线法测得结果进行了对比。结果表明,裂纹柔度法测得距喷丸表面300μm深处的残余压应力为471 MPa,残余压应力场深为900μm;X射线法测得的最大残余压应力在近表层120μm处,为446 MPa,残余压应力场深为820μm;在可比较深度范围内,两种测试法获得的残余应力具有相同变化趋势,且数值大小也接近。     

层错能对冷轧超细晶铜及铜铝合金力学性能的影响(英文)

在液氮温度下(77K)采用冷轧技术制备层错能分别为78、35和7mJ/m2的铜、Cu-2.2%Al和Cu-4.5%Al铜合金。X射线衍射分析表明,冷轧后样品的晶粒尺寸随着层错能的降低而降低,但微观应变、位错密度和孪晶密度则升高。室温拉伸实验表明,随着层错能的降低,铜合金的强度和塑性呈增加,说明降低层错能是一种能够同时提高冷轧铜合金强度和塑性的方法。     

0Cr13Ni4Mo马氏体不锈钢表层的喷丸强化

对经1000℃正火和600℃回火的水轮机过流部件用钢0Cr13Ni4Mo进行喷丸处理,测量了喷丸影响层的显微硬度、X射线衍射线半高宽和屈服强度等参量的沿层深分布,并计算了相应的晶块尺寸、微观应变和位错密度等微观结构参量.结果表明,该影响层以显微硬度和屈服强度表征的组织强化效应显著,显微硬度和屈服强度提高是由于晶块细化、微观应变和位错密度增大造成的.喷丸影响层不同部位的显微硬度与条件屈服点之比约为3.37;半高宽与显微硬度之间存在两段式线性关系:Hw=2.07×10-3 HV-3.47(HV<2835 MPa)和Hw=1.14×10-3 HV-0.81(HV>2835 MPa),条件屈服点与位错密度的平方根之间存在Bailey-Hirsch线性关系: σ0.2S=551+16.2×10-4ρ1/2.     

X-RAY ANALYSIS OF WORK-HARDENING PROCESS FOR POLYCRYSTALLINE а-BRASS DURING UNIAXIAL TENSILE TEST

本文用X射线衍射线形付里叶分析法,得到了含31.55％Zn的黄铜板在室温经不同变形后,位错密度ρ和位错排列参量M随外加应力σ_a大小的变化规律,可以进一步了解范性形变中的加工硬化理论。提出了长程应变与短程应变交替硬化的观点。     

多晶α-黄铜在单轴拉伸实验中加工硬化过程X射线分析

本文用X射线衍射线形付里叶分析法,得到了含31.55%Zn的黄铜板在室温经不同变形后,位错密度ρ和位错排列参量M随外加应力σ_a大小的变化规律,可以进一步了解范性形变中的加工硬化理论。提出了长程应变与短程应变交替硬化的观点。     

氢氧化镍电极材料的层错结构表征

根据氢氧化镍电极材料的X射线衍射谱线的各向异性宽化特性 ,提出层错结构表征方法。采用层错宽化效应的Warren法和Langford谱分解法 ,测算了一些镍电极材料的层错率。结果发现层错率与材料的放电容量存在对应关系 ,放电容量较高 (2 70mA·h/g)的材料层错率达 14.9% ,而放电容量较低 (2 0 7mA·h/ g)的材料层错率为 7.6 %。因此可以用层错率表征氢氧化镍电极材料的电化学性能     

固溶处理对NiTi薄膜中位错密度的影响

用磁控溅射法将NiTi薄膜沉积在纯Cu箔片上，在800℃分别固溶30min，45min，60min和120min：采用X射线傅氏线形分析法计算各固溶时间的位错密度及位错分布参量。随固溶时间的增加，平均位错密度不断下降；亚晶粒尺寸D逐渐增加；平均位错分布参量基本不变。由位错密度及位错分布参量计算得到NiTi薄膜材料的显微硬度值，随固溶时间的增加，显微硬度计算值明显低于测量值。     

纯银和Ag-Ce合金在回复过程中的结构变化

观察与研究了冷变形高纯Ａｇ 和Ａｇ － Ｃｅ （２１ ×１０ － ６） 合金在回复过程中的一系列结构变化, 包括点缺陷减少与消失; 位错环与位错偶极湮灭, 位错密度降低; 形成稳定扩展位错和所谓“Ｙ”结, 层错能降低; 晶格畸变减少和亚晶粒长大等等。回复过程涉及点缺陷、线缺陷和面缺陷综合回复机制。借助于痕量Ｃｅ 的微合金化作用对于上述结构变化和回复软化具有明显抑制作用, 如拟制畸变晶格回复和亚晶长大, 降低Ａｇ 的层错能, 增大回复激活能等。详细讨论了回复过程中亚晶长大机制。     

不锈钢上PVDAg—Cu／Ti双层膜力学性能研究

研究了不锈钢PVDAg－Cu／Ti双层薄膜的力学性能,包括薄膜结合强度、弹性模量、复合硬度及残余应力。结果表明,该双层膜膜基结合良好;用4点弯曲法测得其弹性模量为63．4GPa;薄膜复合硬度表现出导常的负荷依存性;用X射线法测得双层膜膜力应力为张应力,大小为160MPa。     

7A85铝合金时效处理过程中位错密度演变的定量研究

采用X射线衍射（XRD）和透射电镜（TEM）研究了时效温度和时效时间对位错密度的影响,揭示了7A85铝合金时效过程中位错的演变规律。结果表明,当时效温度从80 ℃升高到160 ℃时,位错密度从3.59×10¹⁴ m^-2迅速降低到0.62×10¹⁴ m^-2,降低82.7%。同样,随着时效时间的延长,位错密度降低了41%,时效12 h后,位错密度趋于稳定。TEM结果表明,位错倾向于形成低能位错胞,并逐渐向亚晶转变。最后,根据XRD和TEM的结果,分别对位错纠缠态、位错胞和亚晶粒的位错密度进行了量化。     

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).     

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.     

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.     

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。