基于模糊逻辑的7050铝合金晶粒度自动分析方法的研究（英文）

晶粒度是高强度铝合金微观组织分析的关键参数。通常是由人工手动获得,整个过程耗时且容易出错。目前随着数字图像处理技术和模式识别技术的快速发展,为定量金相分析提供了一种新的方法。利用人工智能实现自动金相分析可以克服手工工艺的缺点。在本文中提出了确定的金相图像的晶粒尺寸的数字图像处理的一种新方法。基于模糊逻辑的边缘检测算法的提取晶界。并对不同方法的金相图像提取方法进行了对比,验证了该方法的有效性。并基于美国材料试验学会(ASTM)标准获得了晶粒度等微观组织参数。     

定量金相及显微硬度分析系统

定量金相及显微硬度分析系统把光机电一体化、定量金相、数字图像处理技术、计算机网络等领域的技术结合在一起,对显微硬度计及硬度测量过程进行全自动智能控制,实现了对金相组织晶粒大小、渗层深度、第二相、孔隙、夹杂等金相参量的自动分析,实现了金相检验资料的智能管理和网络传输.系统应用小波理论、基于数学形态学的区域生长法等方法对采样图像进行分析,实现了对金相图像特征的有效提取,从而实现了定量金相分析自动化.     

金相图像均衡化和多尺度模板二值降噪方法研究

金相图像是金属材料微观形貌的体现,对金相图像进行分析是研究金属材料的重要手段。针对金相图像噪声强、晶界弱、光照不均匀等特点,结合数字图像处理方法,提出了一种金相图像二值降噪方法。首先,采用一种预处理综合方案对图像进行均衡处理。然后采取自适应阈值的方法得到金相二值图像,但仍存在较多噪声。对此,提出一种基于多尺度模板的降噪方法,该方法能有效去除大部分噪声。结果表明,该方法能够得到较好的图像预处理结果和清晰且较为准确的二值化结果,这将有利于后续金相定量分析工作的开展。     

基于数字图像处理技术的金相组织定量分析

论述了基于直方图均衡化方法和基于区域生长及数学形态学方法的金相组织数字图像处理技术,并通过对金相组织中初生相含量的分析结果,对两种方法进行了对比。直方图均衡化分割技术简易、运算速度快,但没有对杂质的区分能力,对各组织区域边缘相互渗透也没有区分能力,易造成分析误差。而区域生长及数学形态学技术可以应用于存在多种组织的金相图像,可以消除区域内的杂质,也可以消除区域间相互渗透的区域,实现较精确的分析,而且在实现区域分割的基础上可以对金相组织的形态进行自动分析。     

图像分析仪在金相检验中的应用

采用标准图谱比较法、定量金相手工测定法和图像仪分析法3种实验方法，对金属材料的晶粒度、特征组织含量和非金属夹杂物进行了对比实验，并分析了实验结果。确认图像仪以其多种优点已成为金相检验的重要检测手段之一。     

基于图像处理技术的多晶体材料金相图像分割算法研究

选取多晶体材料金相图像为研究对象,针对图像边界不连续、纹路噪声严重等特性,应用数字图像处理技术对多晶体材料金相图像进行处理,实现晶粒的准确分割。首先,对多晶体材料的金相图像进行图像平滑、形态学重建等预处理,然后采用改进的分水岭变换法实现图像中晶粒的分割,为多晶体材料的定量分析和三维重建奠定了坚实的基础。     

基于LabVIEW的Sn-Bi合金定量金相分析系统

Sn-Bi合金微观组织形貌中Bi相的晶粒尺寸、数量、形状等特征参数对焊料的力学性能和焊接性能有较大影响,有必要对其进行定量分析。在LabVIEW平台下开发了金相图像的增强、滤波、阈值分割等预处理程序,并实现了金相组织的颗粒度、占比、轴长等参数的统计分析。结果表明,该系统能够快速、高效地对Sn-Bi合金及其他材料的金相组织进行筛选和定量分析,为焊料的韧化机制研究提供参考。     

基于数字图像处理的TC4钛合金金相组织定量分析

通过对TC4钛合金显微组织的金相图片的研究,提出一种对金相定量分析的数字图像处理方法。以ImageJ软件为工具,采用数字图像处理中的图像增强、阈值化、图像分割等数字化处理方法,计算出钛合金组织在不同热处理状态下α相所占比例,以及金相分析中其他的特征参数。研究结果表明:该数字图像处理方法可实现对TC4组织金相图片的处理,在TC4棒材锻件中α相占49.38%,长短轴比为1.458。     

新的单参数动态再结晶动力学建模及晶粒尺寸预测

通过引入动态再结晶的演化速率,分析了基于Avrami方程的经典动态再结晶动力学模型的不足.提出了一种新的具有单参数的动态再结晶动力学模型,反映了动态再结晶过程缓慢快速缓慢的特点.采用Gleeble-1500热模拟试验机,对典型的具有动态再结晶特性的材料镁合金AZ31B进行了热压缩实验,通过进行参数回归得到了其动态再结晶动力学模型,并与实验结果相对比,验证了该模型的正确性.进一步将稳态变形条件下获得的微观组织演化模型改写成分步叠加形式.与动态再结晶晶粒尺寸模型相结合,应用到非隐态条件的晶粒预测,模拟与实验的对比表明计算结果和定量金相法所获得的结果基本一致,说明了非稳态变形过晶粒的叠加预测方法的合理性.     

金相组织计算机图像处理与识别技术研究现状

综述了计算机图像处理与识别技术在金相组织分析中的研究与应用现状,介绍了国内外科技工作者采用计算机进行铸铁金相组织分析、有色金属及合金晶粒度评级、钢铁产品质量检验及焊接接头金相组织分析的部分研究成果,并分析了金相组织计算机图像处理与识别技术的发展趋势.     

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。