燃烧反应工艺制造的TiAl—Ti2AlC复合材料的组织与机械性能

采用磁悬浮区域熔炼的方法制备了ＴｉＡｌ合金ＰＳＴ晶体，然后在８００℃下对其压缩性能和变形组织分别进行了测试和观察。结果表明，在８００℃时的屈服强度取决于片层界面与压缩轴的夹角φ，在φ＝９０°时屈服强度最高，而φ＝４５°时最低。８００℃时屈服强度较室温下的有较大程度下降，这与α２相中锥面滑移系｛１１２１｝〈〈１１２６〉的临界分切应力的降低有关。     

低层错能镍基单晶高温合金压缩行为和变形组织的温度相关性（英文）

在室温至1000℃的范围内，研究温度对一种低层错能镍基单晶高温合金压缩行为和变形组织的影响。研究结果表明，压缩行为和变形组织均表现出温度相关性。室温下该合金具有较高屈服强度，600℃时屈服强度有所下降；随后，随着温度的升高，屈服强度持续增加，并在800℃时达到最大值；在800℃以上时，屈服强度迅速降低。通过透射电子显微镜观察揭示合金变形机制。位错缠结和位错对塞积是室温下屈服强度较高的主要原因。在600℃时，变形机制从反相畴界切割向堆垛层错切割转变，这导致屈服强度略有下降。在800℃时，变形机制以堆垛层错切割为主，而Lomer-Cottrell锁和不同方向堆垛层错之间的反应导致最大的屈服强度。在900℃及以上时，虽然仍存在一些层错，但主要变形机制为位错绕过机制。最后，讨论变形机制和压缩行为的温度依赖性。     

微碳深冲钢板的非｛111｝织构特征及其对,△r值的影响

在生产试制的 Ｓｔ１５微碳深冲钢板中，选择ｒ变化、△ｒ一定和ｒ 一定、△ｒ变化的两组试样，对其进行织构测量及ＯＤＦ分析，进而对织构特征进行了描述，并分析了主要织构对ｒ，△ｒ值的影响特点结果表明：试制的这批 Ｓｔ１５微碳深冲钢板没有出现理想的γ〈１１１〉｜｜ＮＤ取向线织构，而是主要体现为γ取向线（Ψ＝０－９０°，θ＝１９°，φ＝４５°）和围绕γ〈１１１〉｜｜ＮＤ取向线从 Ψ=０°， θ＝５４．７°，φ＝６２．７°螺旋旋转到 ψ＝９０°，θ＝４０°，φ＝４５°的 Ｌ取向线其中， Ｌ取向线主要影响Ｆ值，织构越强γ值越大，但对△γ值不利．γ取向线主要影响面△γ值，织构越强面△γ值越小．但对γ值不利．强的Ｌ取向线织构配以较强的γ＇取向线织构可以获得良好的γ，△γ值．     

新淬火状态2B06铝合金板塑性成形各向异性行为研究

通过与轧制轴成0°、45°和90°方向的单向拉伸试验,研究了2B06铝合金板O态和W态(新淬火态)下材料的强度各向异性(3个方向屈服强度的变化)和塑性流动各向异性(3个方向厚向异性指数的变化)行为。发现,虽然屈服强度和应变硬化受热处理状态影响显著,但强度各向异性和塑性流动各向异性受热处理状态影响较小,均在试验数据分散范围之内。获取的试验数据被用来校准Hill48屈服准则。通过绘制的屈服轨迹发现,对于W态可以采用与O态相同的屈服面形状来描述其材料塑性各向异性行为,这样将显著减少W态下本构模型校准需要的试验数。     

大塑性变形-反应烧结TiAl合金的高温压缩屈服强度

研究了大塑性变形-反应烧结TiAl合金的高温压缩屈服强度。结果表明：高能球磨显著改善了烧结TiAl合金的压缩性能，同时其压缩性能还取决于烧结工艺。球磨1h粉末挤压坯经1250℃烧结4h后，800℃时的压缩屈服强度最高，达到620MPa，且与其实温值相当：而经1250℃烧结不同时间的未球磨粉末烧结体，800℃时压缩屈服强度最高仅为485MPa。因此，采用大塑性变形-反应烧结工艺制备高性能TiAl合金是可行的。     

沉降槽加环形导流板的研究

本文介绍了在φ１×１ｍ的小型沉降槽内设置环形导流板提高沉降槽产能的研究。结果表明，在加料简外、设置φ８００×４３０ｍｍ的导流板，具有溢流产能高，赤泥压缩块，底流液固比小的优点，为提高沉降槽产能提供了新途径。     

温度对Zr-45Ti-5Al-3V合金准静态力学性能的影响

在-100~200℃范围内不同应变速率(10-4,10-3和10-2s-1)下利用准静态拉伸和压缩实验研究了温度对Zr-45Ti-5Al-3V合金力学性能的影响.结果表明,在拉伸条件下,Zr-45Ti-5Al-3V合金具有较高的屈服强度和抗拉强度,室温时其屈服强度超过1355 MPa,但延伸率较小.随着温度的升高,合金的屈服强度和抗拉强度均下降,而塑性变形量则上升.在压缩条件下,温度对屈服强度的影响与拉伸时一致,而塑性变形量和断裂强度均在室温时最高,其他温度下变化规律与拉伸时一致.应变速率对合金的力学性能影响不大.     

自由端扭转对AZ31挤压棒不同温度下压缩行为的影响（英文）

研究自由端扭转对 AZ31 挤压棒不同温度下压缩行为的影响。预扭转会在基体中产生高密度位错和大量的{■}孪晶,从而大大提升室温和100 ℃的压缩屈服强度。然而,随着温度的升高,预扭转产生的硬化效果逐渐减弱。当压缩温度达到 300 ℃时,预扭转降低了压缩屈服强度。此外,扭转产生的初始位错和孪晶有助于细化亚结构,加快 200 ℃压缩过程中的连续动态再结晶。因此,在 200 ℃下,扭转试样比挤压试样表现出更快的流变软化行为。当在 300 ℃时压缩,扭转引入的孪晶和位错在保温时间内基本被消除,不连续动态再结晶得到增强。结果表明,在 300 ℃时,扭转试样和挤压试样的压缩曲线趋于一致。对相关机制进行了详细讨论。     

选区激光熔化成形点阵结构的各向异性对力学性能的影响

选区激光熔化技术（selective laser melting, SLM）成形的金属点阵结构由于具有结构设计自由度大、轻量化、缓冲吸能等优势,在航空航天等领域具有广泛的工程应用前景,然而对其力学性能的研究不够充分。本研究设计了不同方向的体心立方（body-centered cubic, BCC）和金刚石（Dia）两种晶胞点阵结构,基于SLM技术成形了AlSi10Mg点阵结构,并对成形试样进行了压缩试验,结合有限元分析（finite element analysis, FEA）研究了点阵结构的各向异性对其压缩响应和吸能特性的影响。结果表明,两种点阵结构均存在明显的各向异性。在相对密度基本一致的情况下,点阵结构方向从0°到45°,随着角度的增大,屈服强度明显增大,BCC点阵结构的各向异性对其压缩屈服强度的影响更加明显,Dia点阵结构的屈服强度明显高于BCC点阵结构。不同方向点阵结构的比吸能(specific energy absorption, SEA)存在明显差异,点阵结构方向从0°到45°,随着角度的增大,SEA明显增大,Dia点阵结构的SEA明显高于BCC点阵结构。不同方向点阵结构的碰撞载荷效率(crash load efficiency, CLE)存在明显差异,BCC点阵结构在0°方向取得最大值1.07,并随着点阵结构角度的增大逐渐减小,Dia点阵结构CLE随着点阵结构角度的增大而增大,并在45°方向上取得最大值1.01。     

新淬火状态2806铝合金板塑性成形各向异性行为研究

通过与轧制轴成0°、45°和90°方向的单向拉伸试验，研究了2B06铝合金板O态和W态（新淬火态）下材料的强度各向异性（3个方向屈服强度的变化）和塑性流动各向异性（3个方向厚向异性指数的变化）行为。发现，虽然屈服强度和应变硬化受热处理状态影响显著，但强度各向异性和塑性流动各向异性受热处理状态影响较小，均在试验数据分散范围之内。获取的试验数据被用来校准Hill48屈服准则。通过绘制的屈服轨迹发现，对于W态可以采用与O态相同的屈服面形状来描述其材料塑性各向异性行为，这样将显著减少W态下本构模型校准需要的试验数。     

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。