激光熔覆TiC_p/Ni合金涂层中界面结构及界面硬度与弹性模量分布

利用激光熔覆制备了两类ＴｉＣｐ／Ｎｉ合金涂层与自生ＴｉＣｐ涂层不同,在添加ＴｉＣｐ涂层中,ＴｉＣｐ与基体界面处观察到 ＴｉＣ外延生长及 ＣｒＢ．相利用纳米硬度仪研究了涂层中 ＴｉＣｐ与基体的界面硬度 Ｈ及弹性模量 Ｅ的分布添加 ＴｉＣｐ与基体相界面加载的曲线存在位移突进（ｐｏｐ－ｉｎ）现象;原位ＴｉＣｐ界面附近加载曲线不存在ｐｐｐ－ｉｎ现象．原位ＴｉＣｐ相界面附近 Ｈ及 Ｅ较高并呈现连续梯度分布特征,表明原位ＴｉＣｐ界面具有高的刚度与强韧性．     

激光熔覆TiCp/Ni合金涂层中界面结构及界面硬度与弹性模量分布

利用激光熔覆地了两类ＴｉＣｐ／Ｎｉ合金涂层,与自生ＴｉＣｐ涂层不同,在添加ＴｉＣｐ涂层中,ＴｉＣｐ与基体界面处理观察到ＴｉＣ外延生长及ＣｒＢ,相利用纳米硬度仪研究了涂层中ＴｉＣｐ与基体的界面硬度Ｈ及弹性模量Ｅ的分布。添加ＴｉＣｐ与基体相界面加载的曲线存在位移突进（ｐｏｐ－ｉｎ）现象;原位ＴｉＣｐ界面附近加载曲线不存在ｐｏｐ－ｉｎ现象。原位ＴｉＣｐ相界面附近Ｈ及Ｅ较高并呈现连续梯度分布特征。表明原位     

TiCp／ZA43复合材料的制备及其拉伸性能

采用ＸＤ法与搅拌铸造技术相结合的工艺制备了ＴｉＣｐ／ＺＡ４３复合材料,其中ＴｉＣ粒子的尺寸为０．５～１．５μｍ,在基体中分布均匀。对ＴｉＣｐ／ＺＡ４３复合材料室温至２５０℃温度范围的力学性能进行了测试,获得了该复合材料的应力－应变曲线及力学性能与温度的关系,并对其高温拉伸断口进行了分析。结果表明：ＴｉＣ粒子提高了材料的强度,尤其是显著提高了高温强度;ＴｉＣｐ／ＺＡ４３复合材料的断裂方式与拉伸温度有关,在２５０℃时呈现塑性断裂     

Ti—15s／TiCp复合材料的拉伸断裂过程

用金相，ＳＥＭ和ＴＥＭ研究了ＰＴＭＰ技术制备的含１０％体积分数粒子的Ｔｉ－１５Ｓ／ＴｉＣ颗粒强化复合材料的显微组织，拉伸断口及拉断试样纵向显微组织特征，原始复合棒料是等轴晶组织，增强体ＴｉＣ粒子随机分布于基体中，增强体和基体界面连接良好，尺寸较大的ＴｉＣ粒子中有孔洞存在，有拉伸过程中，由于ＴｉＣ粒子是主要的承载体而首先断裂，粒子裂纹快速扩展到基体造成复合体快速断裂，尺寸较大的ＴｉＣ粒子中有原有孔洞     

NiAl—TiC内生复合材料的高温拉伸行为

研究了ＨＰＥＳ法制备的ＮｉＡｌ－ＴｉＣ内生复合材料的高温拉伸行为及ＮｉＡｌ／ＴｉＣ的界面特点，结果表明，内生ＴｉＣ颗粒可大幅度提高ＮｉＡｌ的高温拉伸强度，在ＮｉＡｌ与ＴｉＣ之间存在着一种相互交错的界面，它对提高复合材料的高温拉伸强度具有重要贡献。     

原位TiC颗粒增强铁基复合材料及其组织形成机理

研究了反应铸造工艺制备的原位ＴｉＣｐ／Ｆｅ复合材料的组织和性能,并探讨了复合材料的组织机理。结果表明：原位合成的ＴｉＣ颗粒尺寸细小（４．４８μｍ）、数目多（２１６９个／ｍｍ＾２）且在珠光体基体中分布均匀;ＴｉＣ颗粒与基体的界面干净,无间隙和界面反应产物生成。这些组织特点使所制备的复合材料具有如下平均性能;硬度ＨＲＣ＝４２,。冲击韧性αｋ＝８．６Ｊ／ｃｍ＾２,抗拉强度σｂ＝４２２ＭＰａ,延伸率δ＝１     

喷射沉积Al—5.5Cu／TiB2自生复合材料的界面结构

运用ＴＥＭ观察了铸态、喷射沉积态Ａｌ－５．５Ｃｕ／ＴｉＢ２复合材料中ＴｉＢ２与基体的界面结构,发现在铸态时ＴｉＢ２与ａ（Ａｌ）之间存在的位向关系向「０３３２」ＴｉＢ２∥「１１０」ａ（Ａｌ）,（０１１）ＴｉＢ２∥（００２）ａ（Ａｌ）,而在沉积态时其位向关系为「００１」ＴｉＢ２∥「１１１」ａ（Ａｌ）,（１１２０）ＴｉＢ２∥（２２０）ａ（Ａｌ）。力学性能测试结果表明：喷射沉积后的Ａｌ－５．５Ｃｕ／ＴｉＢ     

金属间化合物γ—TiAl基合金的制备技术,性能及应用

γ一Ｔｉａｌ的诸多特性引起人们的广泛关注．从室温到高温, γ-ＴｉＡｌ的比强度（Ｒｐ０.２／ ｐ）与ＩＮ７１８合金相当,比模量（Ｅ／ｐ）远高于ＩＮ７１８及ＩＭＩ８３４合金,热膨胀系数（ＣＴＥ）介于ＩＮ７１８与Ｔｉ—６Ａｌ－４Ｖ合金之间． γ－ＴｉＡｌ墓合全的加工ＴｉＡｌ的合金成分一般为Ｔｉ－Ａｌ４５－４８－Ｘ１１－３－Ｘ２１－１０－Ｘ２１－１０－Ｘ３＜１Ｘ１＝ Ｃｒ, Ｍｎ, Ｖ;Ｘ２＝ Ｎｂ, Ｔａ, Ｗ, Ｍｏ; Ｘ３＝Ｓｉ,Ｂ,Ｓ．加工路线分铸使冶金（ＩＭ）和粉末冶金（ＰＭ）两大部分．与合金成分有关的…     

Ti—Mo—TiC烧结合金中TiC的腐蚀行为

纯钛虽说具有良好的耐蚀性,但对盐酸、硫酸等非氧化性酸的耐蚀性却不大好．在钛中添加２５％以上的钼时,对这些酸的耐蚀性可有实质上的改进．但这种钛钼合金熔炼时易偏析,因此开发了粉末冶金的Ｔｉ－３０％Ｍｏ合金,并在其中添加碳化物,以提高硬度和耐磨性,如Ｔｉ－Ｍｏ－（３３％～４５％） ＴｉＣ合金等．为明了合金中ＴｉＣ的腐蚀机制,用电位学方法研究了由β－Ｔｉ和ＴｉＣ两相构成的Ｔｉ－Ｍｏ－ＴｉＣ 烧结合金中的硬质相ＴｉＣ在几种酸碱溶液中的腐蚀行为． 使用的试样为Ｔｉ－２０％Ｍｏ－３３％ＴｉＣ合金（ＴＭ－２）和不…     

PHASE EQUILIBRIUM RELATIONSHIPS OF α_2(α)/γ IN THE Ti-Al-Cr TERNARY SYSTEM

采用扩散偶－电子探针法系统测定了Ｔｉ－Ａｌ－Ｃｒ三元系１０００－１３００℃的α２（α）／γ相平衡关系和相平衡成分,给给出Ｃｒ含量小于１０％（原子分数）范围的Ｔｉ－Ａｌ－Ｃｒ三元系局部等温截面和Ｔｉ－Ａｌ局部纵截面相图,明确了Ｃｒ在α２（α）和γ相中分配比的变化规律,研究结果支持Ｃｒ在γＴｉＡｌ相中取代Ａｌ的位置,降低γ－ＴｉＡｌ相中Ａｌ含量的观点。     

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。