沟槽烧结纤维复合毛细芯多孔材料的拉伸性能研究（英文）

通过烧结铜纤维和微沟槽铜板制造得到了一种具有高孔隙率的新型沟槽烧结纤维复合毛细芯多孔材料。通过对沟槽烧结纤维复合毛细芯多孔材料进行拉伸性能测试,研究了纤维参数和烧结参数对拉伸性能的影响。通过大量的拉伸实验数据得到了沟槽烧结纤维复合毛细芯多孔材料的典型的应力应变图。对于在相同的烧结参数下制造得到的相同质量的沟槽烧结纤维复合毛细芯多孔材料,其抗拉强度随着孔隙率和直径的增加而减少。测试结果表明:当烧结温度低于1083℃时,抗拉强度随着烧结温度和烧结时间的增加而增加。     

热柱毛细芯中铜纤维和微沟槽黏附力的研究（英文）

通过多齿铣削和高温烧结制造了微沟槽烧结铜纤维板,通过超声波振动实验测试了烧结参数和铜纤维参数对复合毛细芯中铜纤维和微沟槽壁面黏附力的影响,结果表明:烧结时间、烧结温度、温度上升速率、烧结压力以及纤维参数对热柱复合毛细芯中的铜纤维和微沟槽壁面的黏附力有重要的影响。当烧结温度为900摄氏度,烧结时间60 min,烧结压力为0. 45 MPa,温度上升速率为5℃/s下烧结的烧结层厚度为1 mm时的复合毛细芯中的铜纤维和微沟槽壁面的黏附力最大。     

热柱毛细芯中铜纤维和微沟槽黏附力的研究

通过多齿铣削和高温烧结制造了微沟槽烧结铜纤维板,通过超声波振动实验测试了烧结参数和铜纤维参数对复合毛细芯中铜纤维和微沟槽壁面黏附力的影响,结果表明:烧结时间、烧结温度、温度上升速率、烧结压力以及纤维参数对热柱复合毛细芯中的铜纤维和微沟槽壁面的黏附力有重要的影响。当烧结温度为900摄氏度,烧结时间60 min,烧结压力为0.45 MPa,温度上升速率为5℃/s下烧结的烧结层厚度为1 mm时的复合毛细芯中的铜纤维和微沟槽壁面的黏附力最大。     

多孔复合吸液芯热管制备及传热性能研究

通过电化学沉积处理方法,在铜沟槽管内部制备多孔复合吸液芯。使用扫描电镜对复合吸液芯的表面形貌进行观察,探究了不同电沉积时间对该复合吸液芯毛细性能的影响,并对采用该复合吸液芯的热管传热性能进行研究。结果表明,相对于沟槽吸液芯,经电化学沉积处理过的复合吸液芯具有更好的毛细性能,且毛细性能随沉积时间的增长而减弱。沉积时间为10 min时,复合吸液芯的毛细性能最好,毛细上升高度为49.5 mm;与沟槽吸液芯相比,毛细上升高度提升了62.3%,其对应热管的温差最小,热阻也最低。     

泡沫铜板与铜粉复合烧结多孔材料的制备

介绍了泡沫铜与铜粉的复合多孔材料松装烧结成形工艺;分别采用SEM观察其几何结构特征和称重法,分析了复合多孔材料的收缩率及孔隙率。结果表明,该材料具有大比表面积、高孔隙率特征;采用与纯铜粉烧结类比的方法,探讨了烧结温度、保温时间及铜粉粒径对复合多孔材料的收缩率和孔隙率的影响。结果显示,相比于铜粉烧结多孔材料,泡沫金属与铜粉烧结复合多孔材料具有更小的收缩率及更大的孔隙率。     

多孔微通道的固相烧结制备及其对流传热性能（英文）

提出一种低成本固相烧结制造多孔微通道的方法,设计3种多孔复合微通道,并通过优化烧结工艺,制备具有高孔隙率的多孔复合微通道。研究多孔复合微通道的流动阻力和传热性能。结果表明:在流动阻力可接受的范围内,传热性能显著增强,而且流动沸腾也得到强化。将多孔复合微通道结构应用在对流传热领域具有良好的前景。     

凝胶注模制备多孔Ni-Ti合金的研究

多孔Ni-Ti合金由于其优异的形状记忆性能而广泛应用于医用植入材料领域。本文以TiH2粉及雾化Ni粉为原料,采用凝胶注模成型技术,制备出Ni-Ti凝胶生坯,通过后续真空干燥、脱脂以及烧结工艺成功制备出性能优异的医用植入多孔Ni-Ti合金。运用XRD、SEM对多孔Ni-Ti合金进行了成分及微观结构表征,分析了不同烧结温度对于多孔Ni-Ti合金孔隙率、机械性能、组织成分及微观形貌的影响。结果表明,随着烧结温度的增加,孔隙率降低,抗压强度和杨氏模量增加。对固相体积分数为45vol. %的生坯在1050 ℃条件下高真空烧结保温2h,制备出孔隙率为42.65%,抗压强度为202.65 MPa,杨氏模量为17.14 GPa,主相为NiTi相的多孔Ni-Ti合金,基本满足人体骨性能需要。     

不锈钢纤维多孔材料及其复合结构的隔声性能

本文以8μm不锈钢纤维毛毡为原料,利用体积称重法和高温烧结工艺制备出具有不同孔隙率、平均孔径和厚度的不锈钢纤维多孔材料。通过结构优化设计了正梯度结构、反梯度结构和薄膜复合结构,对三种结构进行了隔声性能的测试,分别研究了三种结构的隔声特性。隔声结果表明,不锈钢纤维多孔材料具有一定的隔声性能,厚度为20mm,孔隙率为85%,在50~6400Hz频率范围内,不锈钢纤维多孔材料的平均隔声量为18.92 dB;其孔隙率越低,平均孔径越小,厚度越厚,材料的隔声性能越好;设计的正梯度和反梯度结构的隔声性能比单层不锈钢纤维多孔材料的隔声性能差;添加金属薄膜的不锈钢纤维多孔复合材料在中高频处的隔声性能有很大提高,厚度为20mm,平均隔声量达27.86dB,最高处提高16.96dB。     

烧结温度对多孑L钛组织结构与性能的影响

分别在1000、1100、1200、1300和1400℃下真空烧结制备了多孔钛试样,并对多孔钛试样进行孔结构、组织结构和性能检测,研究了烧结温度与多孔钛的结构和性能的关系。结果表明:随着烧结温度的提高,多孔钛中颗粒边缘由尖锐变圆滑,孔型由不规则形向圆形转变,烧结颈由细变粗进而出现颗粒表面熔化,孔隙率下降。硬度随烧结温度的提高,呈现先升后降的变化规律,抗压强度逐步提高。     

基于选区激光烧结（SLS）技术成形多孔金属材料的工艺研究

本文基于选区激光烧结技术对多孔金属材料的成型工艺进行了研究，分析了多孔金属的孔隙成形机理，确定了工艺参数对孔隙率的影响规律，为多孔金属材料的仿生制造研究提供可靠依据。     

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。