Timetal 5111和Timetal 5111 0.05Pd钛合金

Timetal5111合金是80年代末期由Timet与美国海军共同开发研制的近a型钛合金。合金成分为：Ti－5Al－1Zr－1Sn－1V－0．8Mo－0．1Si。合金的突出特点是良好的断裂韧性及抗应力腐蚀性能，应力腐蚀危险比，该性能指标优于船用钛合金48－OT3（Ti－4AI－0．005B），相当于Ti－6211（Ti－6Al－2Nb－1Ta－0．8Mo）；冲击韧性大约为Ti－6Al－4V的3倍；易焊接，可进行大型材的焊接。该合金强度略低于Ti－6Al－4V，延性略高于Ti－6Al－4V，σb＝750MPa～800MPa，s≥13％，但通过调整氧含量可使强度达到Ti－6Al－4V的水平。目前可生产重…     

The graded material of 316L stainless steel－Ni-based alloy－Ti6Al4V formed by laser rapid forming process

用激光快速成形法制备了致密、无裂纹的316L 不锈钢(SS)/镍基合金/Ti6Al4V梯度薄壁件. EDS与XRD分析显示, 在316L SS/镍基合金梯度过渡区内为单相$\gamma$奥氏体, 硬度沿316LSS到镍基合金方向逐步增加; 在镍基合金/Ti6Al4V梯度过渡区内,组织变化顺序为: γ→γ+β+TiNi3+Ti2Ni→TiNi3+Ti2Ni+→βTi2Ni+β→α+β+Ti2}Ni→α+β; 过渡区内, Ti6Al4V含量 为20%(质量分数)时, 硬度达到最大值HV10 830, 随后,随Ti6Al4V含量增加, 硬度逐 渐减小.     

Ti6Al4V-0.55Fe合金连续升温过程的相变研究

通过连续升温热膨胀法(DIL)研究了Ti6Al4V-0.55Fe合金在连续升温过程中的α相回溶(α+β→β)的热膨胀行为和显微组织演化。采用了1、5、10、15 K/min的4种升温速率对Ti6Al4V-0.55Fe合金进行热膨胀实验,结果发现:不同升温速率的α相回溶曲线都展现出典型的"S"型曲线,表明α相回溶是一种由形核长大控制的过程。通过Kissinger-Akahira-Sunose(KAS)方法和Kolmogorov-Johnson-Mehl-Avrami(KJMA)模型分别得到α相回溶转变平均相变激活能E和随着α相回溶体积的增大所对应的Avrami指数n,可分为3个阶段,即相变初期(0f0.01)、相变中期(0.01f0.95)和相变终期(0.95f1),表明Ti6Al4V-0.55Fe合金的α相回溶过程机制在不同时期是不同的。同时采用背散射电子像(BSE)进行Ti6Al4V-0.55Fe合金组织演化验证分析,发现α相回溶温度区间与升温速率为15 K/min的热膨胀曲线确定的温度区间885~1043℃相同,增加了热膨胀实验结果的可靠性。最后,结合相转变曲线,给出了合金连续升温过程α+β→β相转变的连续升温相转变图。将Ti6Al4V-0.55Fe与Ti6Al4V合金比较,发现两合金的热动力学差别主要为Ti6Al4V-0.55Fe合金α相回溶平均相变激活能比Ti6Al4V低,表明Ti6Al4V-0.55Fe合金比Ti6Al4V合金的α相回溶更容易。     

TC4-Fe合金连续升温过程的相变研究

通过连续升温热膨胀法(DIL)研究了Ti6Al4V-0.55Fe合金在连续升温过程中的α相回溶（α+β→β）的热膨胀行为和显微组织演化。本文采用了1、5、10、15 K/min的四种升温速率对Ti6Al4V-0.55Fe合金进行热膨胀实验,结果发现：不同升温速率的α相回溶曲线都展现出典型的“S”型曲线,表明α相回溶是一种由形核长大控制的过程。通过Kissinger-Akahira-Sunose（KAS）方法和Kolmogorov-Johnson-Mehl-Avrami(KJMA)模型分别得到α相回溶转变平均相变激活能E和随着α相回溶体积的增大所对应的Avrami指数n,可分为三个阶段,即相变初期（0相似文献   

医用Ti6Al4V合金表面改性研究进展

Ti6Al4V合金因具有优异的力学性能和良好的生物相容性而被广泛应用于人体硬组织替代物和修复物领域。由于合金本身耐摩擦磨损性差,不具备生物活性等缺点,因此对Ti6Al4V合金进行表面改性具有重要意义。本文介绍对Ti6Al4V合金进行改性的有效方法,综述了其表面改性的研究进展,展望了表面改性的发展趋势。     

成分微调对中强钛合金组织与力学性能的影响

通过成分微调在Ti-6Al-4V合金基础上发展了一种基于Ti—Al—V-Si四元系TC4S两相钛合金。研究表明，添加少量合金元素Si，并对Al，V元素含量进行微调，使新合金的主要力学性能得到提高，强度、塑性和断裂韧性得到良好匹配，从而满足了设计要求。TC4S合金可以在不明显降低塑性和韧性的前提下，比Ti-6Al-4VELI合金的强度提高80MPa-100MPa。     

钛及钛合金电弧钎焊及接头强度

用Ti—Cu—Ni，Ti-Cr-Zr钎料在TIG电弧加热条件对TA2和Ti—6Al—4V钛合金进行钎焊。结果表明：用Ti—Cu—Ni钎料钎焊TA2和Ti—6Al—4V钛合金的搭接接头强度分别是418．3MPa和439．6MPa；用Ti—Cr—Zr钎料钎焊TA2和Ti—6Al—4V钛合金的搭接接头强度分别是575．2MPa和656．1MPa。对Ti-Cu-Ni钎料／母材界面分析认为固液异分化合物η相((Cu，Ni)Ti2)生成时呈笋状生长，嵌入钎缝对钎缝的强度提高有利。对Ti-Cr-Zr钎料／母材界面分析，认为主要是固溶体β-Ti(Cr)存在提高了钎缝强度。     

Ti6Al7Nb和Ti6Al4V合金的热氧化行为

在600～900℃温度下,0.5～72 h时间范围内空气气氛下对Ti6Al7Nb进行热氧化,根据增重曲线计算其氧化动力学规律,利用XRD、XPS分析表面氧化层的相组成、成分和价态,并以Ti6Al4V合金做为比照.结果表明,Ti6Al7Nb合金较Ti6Al4V合金抗氧化能力更强.同等氧化条件下,Ti6Al7Nb合金的氧化速率常数(k)更小.对短时间(1 h)氧化的样品的表面分析显示:各合金元素均以最高价态或稳定价态存在,其中Al和V被富集,而Nb则贫化;另外,Ti6Al7Nb合金和Ti6Al4V合金氧化层主要由金红石型TiO2(R-TiO2)组成,Al2O3相仅出现在900 ℃Ti6Al4V合金样品中.     

Ti6Al4V车削刀具磨损及切削力研究

Ti6Al4V是典型的难加工材料，切削效率低、刀具磨损严重严重，因此提高Ti6Al4V的加工效率和刀具寿命是急需解决的问题。作者对硬质合金刀具加工Ti6Al4V的切削力和磨损特性进行了实验研究。对三种不同刀具在干切削状态下车削Ti6Al4V切削力进行了试验，分析了切削力与切削速度、切削路程的关系，同时讨论了主偏角对TC4车削稳定性的影响。最后，对刀具的的磨损形态和磨损机理进行了研究。粘结、扩散、氧化是硬质合金刀具的主要磨损机理。     

Ti6Al4V合金相变及吸氢热力学研究（英文）

在823～1023 K的氢化温度范围内对Ti6Al4V合金进行了压力-成分等温线测试,研究了Ti6Al4V合金的相变和吸氢热力学。结果表明,当Ti6Al4V合金在不同的氢化温度下进行置氢处理时,氢压随着氢含量的增加而逐渐升高。由于Ti6Al4V合金中原始β相的存在,在置氢处理过程中,每个压力-成分等温线只有一个倾斜的压力平台。根据Vant’s Hoff定律,压力平台区的焓变值和熵变值分别为-50.7±0.26 k J/mol和-138.4±0.69 J·K~(-1)·mol~(-1)。随着置氢温度的升高,Sieverts常数呈先增大后逐渐减小的趋势。分析了Ti6Al4V合金在置氢处理过程中的相组成和相变。     

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。