AlCrTaTiZrV高熵合金氮化物扩散阻挡层的制备及其热稳定性

为研究氮气含量的变化对AlCrTaTiZrV高熵合金薄膜性能的影响,检验在最佳氮气含量下厚度为15 nm的(AlCrTaTiZrV)N扩散阻挡层的热稳定性。采用直流磁控溅射设备在N型Si(111)基底上溅射不同氮气含量的高熵合金氮化物;选取最佳氮气含量为制备条件,在硅基底上沉积15 nm厚的AlCrTaTiZrVN₁₀高熵合金氮化物为扩散阻挡层,并在阻挡层顶部沉积50 nm厚度的Cu膜,最终形成Si/AlCrTaTiZrVN₁₀/Cu三层堆叠结构。利用真空退火炉将Si/AlCrTaTiZrVN₁₀/Cu薄膜体系在500 ℃下进行不同时间的退火处理,用以模拟恶劣的工作环境。利用场发射扫描电子显微镜(FESEM)、原子力显微镜(AFM)、X射线衍射仪(XRD)及四探针电阻测试仪(FPP)对试样的表面形貌、粗糙度、物相组成及方块电阻和进行表征。试验结果为:当氮气含量低于10%时,高熵合金氮化物薄膜为非晶结构。当氮气含量为20%时,高熵合金氮化物薄膜呈现FCC结构,并随着氮气含量的增加,薄膜的结晶性得到提高。薄膜表面的粗糙度在氮气含量为10%时最低,R_a仅为0.124 nm。三层堆叠结构500 ℃退火8 h后,Cu表面发生团聚,薄膜的方阻维持在较低的0.070 Ω/□,且并未发现Cu-Si化合物。厚度为15 nm的非晶结构AlCrTaTiZrVN₁₀薄膜在500 ℃退火8 h后,依旧可以抑制Cu的扩散,表现出了优异的热稳定性及扩散阻挡性能。     

AlCrTaTiZrMo高熵合金氮化物扩散阻挡层的制备与表征

目的 制备15 nm的(AlCrTaTiZrMo)N六元高熵合金氮化物薄膜,并对其扩散阻挡性能进行表征。方法 使用直流磁控溅射设备在单晶硅上沉积(AlCrTaTiZrMo)N高熵合金氮化物薄膜,然后在薄膜上沉积150 nm的Cu,形成Cu/(AlCrTaTiZrMo)N/Si结构。在600 ℃下,对该结构进行不同时间的退火处理,使用X射线衍射仪（XRD）、四探针测试仪（FPP）、原子力显微镜（AFM）和场发射扫描电子显微镜（FESEM）研究薄膜成分及退火时间对薄膜组织结构、表面形貌、方块电阻的影响,研究其扩散阻挡性。结果 高熵合金氮化物薄膜与基体Si和Cu的结合性较好。沉积态高熵合金氮化物薄膜为非晶结构,表面光滑平整,方块电阻阻值较低。在600 ℃下经1 h退火后,薄膜仍为非晶结构,表面发生粗化。随着退火时间增加,5 h退火后,结构中出现少量纳米晶,大部分仍为非晶,表面粗糙度增加。退火7 h后,结构没有发生变化,仍为非晶包裹纳米晶结构,Cu表面生成部分岛状物,方块电阻阻值仍然较低,且无Cu-Si化合物生成,证明(AlCrTaTiZrMo)N高熵合金氮化物薄膜在长时间退火处理后,仍能保持良好的铜扩散阻挡性。结论 15 nm的(AlCrTaTiZrMo)N高熵合金氮化物薄膜在600 ℃下退火7 h后,其非晶包裹纳米晶的结构能有效阻挡Cu的扩散,表现出了优异的热稳定性与扩散阻挡性。     

VNbMoTaWCo高熵合金氮化物扩散阻挡层的制备及其热稳定性

利用直流磁控溅射镀膜机设置不同氮气流量参数,制备VNbMoTaWCoN_x薄膜,氮气流量为20%时,在洁净的硅基底上沉积厚度约为15 nm的VNbMoTaWCoN₂₀高熵合金氮化物薄膜,并在其上面再溅镀一层厚度约为50 nm的Cu膜,最终形成Cu/VNbMoTaWCoN₂₀/Si 三层复合结构。采用四点探针电阻测试仪(FPP)、X射线衍射仪(XRD)、原子力显微镜(AFM)、场发射扫描电镜(SEM)对三层复合结构500 ℃退火前后的方块电阻、物相结构、粗糙度以及表面形貌进行了分析表征,研究了VNbMoTaWCoN₂₀高熵合金氮化物薄膜作为扩散阻挡层的热稳定性。研究结果表明,当氮气流量占比为20%时,VNbMoTaWCo₂₀高熵合金氮化物薄膜为非晶态,且出现了微量纳米晶;此氮气流量占比下制备的薄膜表面平整光滑、致密度最佳、粗糙度数值最小。Cu/VNbMoTaWCoN₂₀/Si三层复合结构进行500 ℃退火8 h后,Cu膜的方块电阻仍然维持在较低的数值,即0.065 Ω/sq,虽然Cu膜发生团聚,但是并未检测到高阻态Cu-Si化合物。VNbMoTaWCoN₂₀高熵合金氮化物薄膜作为扩散阻挡层在500 ℃温度下退火8 h后,表现出了优异的热稳定性。     

高熵合金AlCrTaTiZrRu/(AlCrTaTiZrRu)N0.7扩散阻挡层的制备与性能研究

目的 验证15 nm厚度AlCrTaTiZrRu/(AlCrTaTiZrRu)N0.7的势垒层热稳定性和扩散阻挡性能。方法 采用直流磁控溅射技术在n型Si(111)基片上真空溅射沉积15 nm的AlCrTaTiZrRu(3 nm)/(AlCrTaTiZrRu)N0.7 (12 nm)双层阻挡层,随后在双层AlCrTaTiZrRu/(AlCrTaTiZrRu)N0.7薄膜的顶部沉积50 nm厚的Cu膜,最终制得Cu/AlCrTaTiZrRu/(AlCrTaTiZrRu)N0.7/Si复合薄膜试样。将样品在真空退火炉中分别进行600~900 ℃高温退火30 min,以模拟最恶劣的应用环境。用场发射扫描电镜(FE-SEM)、X射线衍射仪(XRD)、能谱分析仪(EDS)、四探针电阻测试仪(FPP)以及原子力显微镜(AFM)对试样的表面形貌、物相组成、化学成分、方块电阻和粗糙度进行表征分析。结果 沉积态AlCrTaTiZrRu/(AlCrTaTiZrRu)N0.7薄膜呈现非晶结构,与Cu膜和Si衬底的结合良好。在800 ℃退火后,Cu/AlCrTaTiZrRu/(AlCrTaTiZrRu)N0.7/Si薄膜系统结构完整,膜层结构界面之间未出现分层现象,表面Cu颗粒团聚现象加剧,Si衬底和Cu膜表面未发现Cu-Si化合物生成,薄膜方阻保持在较低的0.070 ?/sq;900 ℃退火后,薄膜系统未出现层间分离和空洞现象,Cu膜表面形成孤立的大颗粒Cu-Si化合物,薄膜电阻率大幅上升。结论AlCrTaTiZrRu/(AlCrTaTiZrRu)N0.7双层结构在800 ℃退火后仍能有效抑制Cu与Si相互扩散,其非晶结构增强了Cu/HEA/HEAN0.7/Si体系的热稳定性和扩散阻挡性。     

AlCrTaTiZrN_x高熵合金纳米涂层的微观组织和力学性能研究

通过热压方法制备AlCrTaTiZr高熵合金合金靶材,采用磁控溅射方法在抛光后Si基体表面制备AlCrTaTiZrNx高熵合金涂层,并用扫描电镜、X射线衍射和纳米压痕仪等研究了靶成分、相结构及涂层的微观形貌、成分和常规力学性能。结果表明,AlCrTaTiZr高熵合金靶材为体心立方结构,AlCrTaTiZrNx高熵合金薄膜均匀致密,未通入氮气的薄膜为非晶态,通入氮气的薄膜晶体结构均为简单的面心立方结构。当氮气流量百分比为10%时,薄膜力学性能最好,其硬度和杨氏模量分别达到了22.9GPa和234.77GPa。     

Cu互连中Ta-Si-N/Zr阻挡层热稳定性的研究

用射频反应磁控溅射的方法在Si(100)衬底和Cu膜间制备Ta-Si-N(10 nm)/Zr(20 nm)双层结构的扩散阻挡层.Cu/Ta-Si-N/Zr/Si样品在高纯氮气的保护下从600至800℃退火1 h.通过四探针电阻测试仪(FPP)、SEM、XRD和AES研究Cu/Ta-Si-N/Zr/Si系统在退火过程中的热稳定性.结果表明:沉积到Zr膜上的Ta-Si-N表面平坦,为典型的非晶态结构;Cu/Ta-Si-N/Zr/Si样品650℃以上退火后Zr原子扩散到Si中形成的ZrSi2能有效地降低Ta-Si-N与Si之间的接触电阻;Ta-Si-N/Zr阻挡层750℃退火后仍能有效地阻止Cu的扩散.     

直流磁控溅射制备Zr-B-O薄膜及其热稳定性

利用直流磁控溅射技术在Si(100)基底上制备了不同偏压的Zr-B-O和Cu/Zr-B-O薄膜体系,采用扫描电镜(SEM)、X射线衍射(XRD)和透射电镜(TEM)等对薄膜样品的微观组织形貌和热稳定性进行表征分析.结果 表明:不同偏压得到的Zr-B-O薄膜均为非晶结构,薄膜表面平整,膜厚均匀,膜基结合良好,薄膜方阻随偏压增加而减小;当退火温度低于750℃时,Cu膜表面完整连续,方阻较小,750℃退火后,由于Cu膜严重聚集并出现孔洞导致薄膜不连续而使电阻增加,但未发生Cu与Si的扩散,说明非晶Zr-B-O薄膜仍可以有效阻挡扩散.     

CoCrFeMnNi高熵合金作为中间层的Cu/304不锈钢扩散连接研究

将CoCrFeMnNi高熵合金作为中间层,采用真空固态扩散方法实现Cu/304不锈钢的连接,通过SEM、EDS以及显微硬度测试,研究温度对扩散反应机理及性能的影响,采用Fick第二定律计算Cu/Fe原子在高熵合金中的扩散系数,借助XRD以及高熵合金中固溶体相形成判据分析扩散界面的相组成。结果表明:在800～900℃下,高熵合金与Cu和304不锈钢分别实现了稳固连接,界面处发生了元素的互扩散,随着温度的升高,Cu/Fe在高熵合金中的平均扩散系数增加;Cu/CoCrFeMnNi高熵合金和CoCrFeMnNi高熵合金/304不锈钢扩散界面处均未形成脆性金属间化合物;扩散界面处硬度呈连续变化趋势。研究表明,CoCrFeMnNi高熵合金是一种可用于Cu/304不锈钢异种材料扩散连接的阻挡层材料。     

Zr层插入对Ta-N扩散阻挡性能的影响

在不同的沉积温度下,用射频反应磁控溅射方法在Si(100)衬底和Cu膜间制备Ta-N/Zr阻挡层,研究Zr层的插入对Ta-N扩散阻挡性能的影响.结果表明:不同沉积温度下制备的Ta-N均为非晶态结构;Zr层的插入使Ta-N阻挡层的失效温度至少提高100℃,在800℃仍能有效地阻止Cu的扩散.阻挡性能提高的主要原因是高温退火时形成低接触电阻的Zr-Si层.     

W-Ti-N薄膜的制备及其热稳定性

以W-10%Ti二元合金靶材为原材料,采用直流磁控溅射法在Si基体上制备了W-Ti-N三元薄膜,研究了N_2分压和溅射功率对薄膜相结构和N含量的影响;在W-Ti-N/Si结构的基础上制备了Cu/W-Ti-N/Si多层结构,并对其在不同的温度下进行真空热处理。结果表明:通过调整N_2分压和溅射功率,即N_2/Ar比为1∶3且功率为70 W时可以获得非晶态W-Ti-N薄膜。薄膜在700℃以下热处理时具有非常好的热稳定性,方块电阻小于0.6Ω/□,略高于退火前的0.285Ω/□。但退火温度超过700℃后,稳定性迅速下降,在800℃退火后方块电阻达到170Ω/□。Cu布线用W-Ti-N非静态薄膜扩散阻挡层退火过程中的失效机理主要为元素间的界面扩散及反应。     

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。