溅射Ni-5Cr-5Al纳米晶涂层抗高温氧化性能

研究了一种低Ｃｒ、低Ａｌ的Ｎｉ－Ｃｒ－Ａｌ系合金Ｎｉ－５Ｃｒ－５Ａｌ（摩尔分数,％）溅射涂层的抗高温氧化性能。结果表明,虽然Ｎｉ－５Ｃｒ－５Ａｌ溅射涂层在１０００℃氧化２０００小时后外面表生成ＮｉＯ,ＮｉＡｌ２Ｏ４、Ａｌ２Ｏ等复杂氧化物,但表现出很高的抗高温氧化性能。进一步分析表明,这一方面与溅射纳米晶涂层上生成的外氧化物粘附性好有关,另一方面与在ＮｉＯ,ＮｉＡｌ２Ｏ４和涂层之间生成一导听α－Ａｋ     

溅射Ni-5Cr-5Al纳米晶涂层高温氧化

研究了一种低Ｃｒ,低Ａｌ的溅射Ｎｉ－５Ｃｒ－５Ａｌ（原子百分数）纳米晶涂层在９００℃的高温氧化行为,观察并分析了不同氧化时间涂层表面氧化物的生成情况。发现由于Ａｌ,Ｃｒ含量较低,不能生成一层完整的Ａｌ２Ｏ３或Ｃｒ２Ｏ３保护膜,而是生成一种由ＮｉＯ,ＮｉＡｌ２Ｏ３４尖晶石相和Ａｌ２Ｏ３组成的复杂氧化物。     

溅射Ni—Cr—Al—Ti涂层高温氧化过程中组织变化对生成TiO …

观察了溅射Ｎｉ－９．７Ｃｒ－５．５Ａｌ－７Ｔｉ（质量分数）纳米晶涂 高温氧化过程中的组织变化,探讨了溅射涂层表面氧化膜以及涂层预氧化９０ｍｉｎ后磨去生成的氧经膜再重新氧化生成氧化膜中ＴｉＯ２的生长,认为溅射涂经过程中Ｎｉ３（ＡｌＴｉ）相的析出与ＴｉＯ２的生成长大有着密切关系,对两种不同民政部下Ｎｉ３（ＡｌＴｉ）相对ＴｉＯ２生长的影响机制进行了分析。     

退火对亚微结晶钛及BT8钛合金减震性和弹性的影响

对Ｎｉ－９．７Ｃｒ－５．５ｌ－７Ｔｉ溅射纳米晶涂层进行了空气中高温氧化实验,观察并分析了Ｔｉ的作用及影响,研究结果表明：由于涂层中相对较高的Ｔｉ含量,１０００℃氧化２００ｈ后生成了由α－Ａｌ２Ｏ３和ＴｉＯ２组成的复杂氧化膜。ＴｉＯ的存在并没有降低涂层的抗高温氧化性能,而且生成的氧化膜与涂层基体有着很好的粘附性。这主要在于氧化初期生成的ＴｉＯ２在随后氧化过程中没有发生长大,从而保证了保持性氧化膜的完     

微晶化对Ni-5Cr-5Al合金氧化产物的影响

利用磁控溅射在Ｎｉ－５Ｃｒ－５Ａｌ（原子数,％）合金上制备与基体相同成分的微晶涂层,获得的涂层在１０００℃空气进行了氧化实验。结果表明,２００ｈ氧化后涂一成了分层结构的氧化膜：外层为ＮｉＯ和ＮｉＡ１２Ｏ４,内层为连续致密的α－Ａ１２Ｏ３。微晶化使得Ｎｉ－Ｃｒ－Ａｌ系三元合金表面生成一层连续Ａ１２Ｏ３所需的Ｃｒ、ＡＬ含量大大降低。     

MCrAlY涂层对TiAl金属间化合物抗高温氧化性能的影响

研究了溅射Ｃｏ－３０Ｃｒ－６Ａｌ－０．５Ｙ及Ｎｉ－３０Ｃｒ－６Ａｌ－０．５Ｙ涂层对ＴｉＡｌ金属间化合物抗高温氧化性能的影响。结果表明，在９００℃－１０００℃范围内，ＣｏＣｒＡｌＹ，ＮｉＣｒＡｌＹ涂层表面由于可形成粘附性良好的Ａｌ２Ｏ３膜。大大改善了ＴｉＡｌ金属间化合物的抗氧化性能。     

K17F高温合金溅射微晶层的抗高温氧化行为

研究了铸态高温合金Ｋｌ７Ｆ及其溅射微晶（小于０．ｌμｍ）层的高温氧化行为．结果表明，微晶层为均匀的γ相组织，它大幅度提高铸态合金的９００至１０００℃的抗氧化性能，甚至比渗Ａｌ涂层还好在高温下，Ｋ１７Ｆ生成以Ａｌ２Ｏ３为主，含有Ｎｉ，Ｃｒ，Ｔｉ氧化物的氧化膜，它在氧化过程中易剥落，而溅射微晶层表面只生成单一的α－Ａｌ２Ｏ３膜，具有优异的防护性和粘附性，在５００ｈ的氧化过程中未见剥落．     

微晶化对Ni-5Cr-5A1合金氧化产物的影响

利用磁控溅射在Ｍ－５Ｃｒ－５Ａ１（原子分数,％）合金上制备与基体相同成分的微晶涂层．获得的涂层在 １０００℃空气中进行了氧化实验．结果表明, ２００ ｈ氧化后涂层表面生成了分层结构的氧化膜：外层为ＮｉＯ和ＮｉＡ１２Ｏ４,内层为连续致密的α－Ａ１２Ｏ３．微晶化使得Ｎｉ－Ｃｒ－Ａ１系三元合金表面生成一层连续Ａ１２Ｏ３所需的Ｃｒ、Ａ１含量大大降低．     

涂层对Ti60合金高温氧化性能及力学性能的影响

研究了四种涂层对Ｔｉ６０合金高温氧化性能及热暴露后力学性能的影响。在７００－８００℃下,溅射纯Ａｌ,Ｔｉ－３６Ａｌ,Ｎｉ－１６Ｃｒ０２．５Ａｌ（均为质量分数,％）和反应溅射Ａｌ２Ｏ３涂层大大降低了Ｔｉ６０合金的氧化速率。综合考虑涂层的抗氧化性能及涂层基材的相容性,７００℃时,Ａｌ２Ｏ３涂层的效果较好;而８００℃时,ＴｉＡｌ支的效果较好,四种涂层不同程度地提高了Ｔｉ６０合金热暴露后（６００℃,１００     

TiAlCr涂层对TiAl金属间化合物抗高温氧化性能的影响

研究了溅射Ｔｉ－５０Ａｌ－１０Ｃｒ涂层在８００－１０００℃对ＴｉＡｌ金属间化合物抗高温氧化性能的影响。结果表明,ＴｉＡｌ合金由于形成Ａｌ２Ｏ３和ＴｉＯ２的混合氧化物而表现出较差的抗高温氧化性能,而ＴｉＡｌＣｒ层由于形成粘附性了的Ａｌ２Ｏ３膜而大大提高了ＴｉＡｌ的恒温及循环氧化性能,经９００℃１０００ｈ长时间氧化。ＴｉＡｌＣｒ涂层对ＴｉＡｌ合金仍能提供很好的防护,涂层和基格结合我孔洞及裂纹出现,表现     

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。