铝表面改性SiOx薄膜力学性能研究

采用常压化学气相沉积(APCVD)技术在铝基底上成功制备了改性SiOx陶瓷薄膜.通过显微硬度测试与涂层附着力自动划痕测试定量研究了薄膜显微硬度和膜基结合强度,利用光学显微镜(OM)和扫描电子显微镜(SEM)观察了薄膜的原始表面以及压痕、划痕形貌.结果表明,SiOx膜层由大小不均匀的等轴状颗粒团聚堆垛而成,退火处理时长大或融合成片状;SiOx薄膜有效提高纯铝表面的硬度,并能通过SiOx薄膜变形以松弛表层应力,抑制脆性裂纹产生;划痕测试证明基底和薄膜具有很高的结合强度,薄膜与基底发生塑性变形而不剥离.     

铝表面改性SiOx薄膜力学性能研究

采用常压化学气相沉积（APCVD）技术在铝基底上成功制备了改性SiOx陶瓷薄膜。通过显微硬度测试与涂层附着力自动划痕测试定量研究了薄膜显微硬度和膜基结合强度，利用光学显微镜（0M）和扫描电子显微镜（SEM）观察了薄膜的原始表面以及压痕、划痕形貌。结果表明，SiOx膜层由大小不均匀的等轴状颗粒团聚堆垛而成，退火处理时长大或融合成片状；SiOx薄膜有效提高纯铝表面的硬度，并能通过SiOx薄膜变形以松弛表层应力，抑制脆性裂纹产生；划痕测试证明基底和薄膜具有很高的结合强度，薄膜与基底发生塑性变形而不剥离。     

铝表面SiOx薄膜结合性能与机理研究

应用化学气相沉积（CVD）方法在铝表面形成SiOx陶瓷涂层，通过弯曲实验研究了涂层与基体的结合性能。利用扫描电子显微镜（SEM）观察了弯曲部位的表面形貌，弯曲过程表述为表面凹坑与内部孔洞联合长大，形成长条裂纹状沟槽或突脊，最后裂纹长大直至断裂。研究表明，基底与膜层结合良好，形成高结合力的原因是铝基底与表面SiOx膜层间过渡层中的Al-O与Si-O键合能很高，键合稳定。     

具有高结合强度的铝基片SiOx陶瓷膜层CVD制备

采用常压CVD方法在铝合金基底上制备出硅氧化合物陶瓷膜层.使用SEM、TEM及XPS仪分析了膜层形貌、成分和组织结构,通过180°、90°弯曲实验和450 ℃热冲击实验考察了陶瓷膜层与基片的结合性能,证实该技术制备的膜层与基底的结合强度很高.     

SiC颗粒增强体对铝基复合材料微弧氧化膜生长的影响

用微弧氧化方法在SiCp／2024铝基复合材料表面沉积出较厚的陶瓷膜,测定了陶瓷膜的生长曲线和相组成,提出了金属基复合材料微弧氧化膜生长模型．结果表明,微弧放电烧结作用下,膜层内SiCp增强体大部分已被熔化并氧化,只有少数残余的SiCp颗粒仍然保留在靠近界面的膜层内．SiCp增强体阻碍了微弧氧化膜的生长,但它并未破坏微弧氧化膜的完整性,这同铝基复合材料阳极氧化膜结构完全不同．     

不锈钢-铝复合材料表面微弧氧化陶瓷膜的研究

采用微弧氧化的方法在不锈钢-铝复合材料表面获得陶瓷膜.对该膜层进行了断面形貌观察和X-射线衍射分析、耐磨分析,研究了膜层的厚度随微弧氧化时间的规律,结果表明:陶瓷膜层厚度随时间的增加而增加,但有一个极限值.陶瓷层主要由α-Al2O3和γ-Al2O3组成.     

钻杆接头表面陶瓷膜层的制备和性能研究（英文）

利用低压化学气相沉积技术(LPCVD),在钻杆接头表面制取Ti、Cr、Al的氮化物、碳化物和氧化物构成的金属陶瓷膜层。陶瓷膜的特性通过SEM、EDS和XRD分析。结合性能和腐蚀性能分别通过划痕试验和腐蚀实验测试。结果表明:陶瓷膜层致密而均匀,膜厚度在15μm左右,且在膜层与基体之间还形成了一层厚5μm左右的过渡层。陶瓷复膜与基体材料结合性能良好,具有较好的致密性,不存在裂纹气孔等缺陷。陶瓷膜层有效阻隔了有害原子或离子与基体钢的接触,防止材料发生氢鼓泡、氢致开裂等,大大提高了钻杆接头材料的抗腐蚀性能。     

CeO_2对2A12铝合金微弧氧化膜层组织和性能的影响

在硅酸盐电解液中添加稀土二氧化铈(Ce O2)颗粒,采用恒流模式在2A12铝合金表面制备陶瓷膜层。通过扫描电子显微镜、X射线衍射仪、粗糙度仪、硬度计、极化曲线等手段研究Ce O2颗粒对2A12铝合金微弧氧化陶瓷膜层微观形貌、组织、粗糙度、硬度和耐蚀性的影响。实验结果表明:添加Ce O2使膜层表面微孔直径减小,膜层粗糙度下降,厚度增加。Ce O2颗粒进入膜层中大部分以Ce O2化合物沉积形式存在,微量Ce O2参与反应以Ce O、Ce Al11O8化合物形式存在。Ce O2颗粒具有促进γ-Al2O3向α-Al2O3转变的作用,从而提高了膜层的硬度。当Ce O2浓度为3~4 g/L时膜层耐蚀性能较好。     

用微弧氧化法在TC4合金表面制备含钙、铝、磷陶瓷膜陶瓷膜

为提高钛合金的耐海水和生物腐蚀性能,在其表面用微弧氧化法生长一层含钙、铝、磷元素的陶瓷膜.经XRD、能谱、扫描电镜和电子探针测试,发现在钛基体上生长了一层厚约为1 5μm的均匀致密的陶瓷膜,膜中存在磷和铝的晶态,钙以非晶态存在,钙、铝、磷之比约为234;通过循环伏安测试,发现有陶瓷膜层的钛合金的耐腐蚀能力明显增强.     

微等离子体氧化陶瓷膜对钛合金接触腐蚀的影响

在铝酸钠溶液中,利用微等离子体氧化技术,在TC4钛合金表面原位生长复合氧化物陶瓷膜,研究了陶瓷膜的相组成、形貌和陶瓷膜对钛合金接触腐蚀的影响.陶瓷膜由Al2TiO5,α-Al2O3和Rutile TiO2构成;整个膜层由致密层和疏松层组成.陶瓷膜层改善了钛合金与LY12铝合金和H62黄铜的接触腐蚀,陶瓷膜层使得钛合金与LY12铝合金电偶对的电偶电流降低为原来的1/7,使得钛合金与H62黄铜的电偶电流降低为原来的1/2.     

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。