退火工艺对钎焊铝箔抗下垂能力的影响

研究了中间退火工艺以及最终成品退火工艺对3003-Zn钎焊铝箔组织和性能的影响.采用偏振光金相技术和TEM分析了铝箔的微观组织,测量了经不同热处理工艺后铝箔的抗拉强度及其成品的抗下垂性.试验结果表明,中间退火工艺为380℃×2 h时铝箔发生完全回复再结晶,且具有大晶粒组织.成品退火消除了铝箔的亚晶结构,有大量化合物析出相,显著提高铝箔的抗下垂能力.     

AA8079双零铝箔的中间退火工艺

用扫描电镜、透射电镜研究了不同退火工艺条件下0.04 mm厚AA8079冷轧态铝箔第二相的演变规律,并测试了其显微硬度值的变化情况。 结果表明,当退火工艺为200 ℃×6 h时,析出短棒状的β_b(AlFeSi)相和细小粒状α_c(AlFeSi)相;当退火工艺为350 ℃×6 h时,发生了β_P(AlFeSi)相到α_c(AlFeSi) 相转变,且析出型α_c(AlFeSi) 相有些在晶内析出,有些沿位错线附近析出;AA8079铝箔的最佳中间退火工艺为400 ℃×6 h     

高温退火对阴极铝箔腐蚀性能的影响

采用扫描电子显微镜、透射电镜分析和腐蚀量试验，研究了高温退火对铝箔第二相形貌及分布和对阴极箔腐蚀性能的影响。结果表明：3003合金中第二相粒子呈条状时，其周围基体中的位错密度分布不均，尖角部位位错密度高，成为优先腐蚀的区域，导致阴极箔腐蚀形貌不均，易发生剥落腐蚀；第二相粒子呈球状且弥散分布时，阴极箔的腐蚀均匀性好，无剥落腐蚀；在630℃高温下退火，第二相发生溶解，并在空冷时重新析出，重新析出的第二相数目减少，形状细小且弥散分布在基体中，从而提高了铝箔的抗腐蚀性能和腐蚀均匀性。630℃退火4h为最佳工艺。     

国产热轧铝箔毛料和巴林热轧铝箔毛料的比较研究

采用光学显微镜、扫描电子显微镜,透射电子显微镜、X-射线衍射仪,能谱仪等手段比较研究了1235国产热轧铝箔毛料和巴林热轧铝箔毛料的显微组织.研究表明:两种热轧铝箔毛料中化合物相的类型不同,两种热轧铝箔毛料都含有FeAl3相和α(FeSiAl)相,而国产热轧铝箔毛料中还含有β(FeSiAl)相;巴林热轧铝箔毛料的化合物相分布比国产热轧铝箔毛料更均匀;国产热轧铝箔毛料的晶粒尺寸相对较大,巴林热轧铝箔毛料的晶粒尺寸相对较小.     

机械合金化-退火法制备铁硅金属间化合物

用机械合金化一真空退火法成功地制备了铁硅金属间化合物，并用X射线衍射分析了球磨时间、退火工艺对混合粉末结构变化的影响。试验结果表明：球磨30h后有少量FeSi和FeSi2化合物析出；球磨50h后生成大量的FeSi、FeSi2化合物，但有少量的单质铁、硅存在。利用950℃x2h退火工艺处理不同球磨时间的混合粉末，最终得出最佳球磨时间为20h．该球磨时间的混合粉末退火后完全生成以FeSi2、FeSi为主的金属间化合物。     

热处理工艺对亚稳定β型钛合金组织与拉伸性能的影响

对新型Ti-Al-Mo-V-Cr-Fe系亚稳定β型钛合金进行不同工艺热处理，随后进行室温拉伸性能检测，并用扫描电镜(SEM)和X射线衍射仪(XRD)对不同热处理工艺下合金的显微组织和相组成进行分析。结果表明，合金在α+β两相区温度750℃单次退火后的组织中存在大量等轴状α相，在β单相区温度820℃单次退火后的组织由粗大的β晶粒组成。合金经单次退火后的合金强度较低而塑性较高，此时断口形貌中韧窝数量较多；再经750℃×1 h+540℃×8 h和820℃×1 h+540℃×8 h双重退火后的显微组织中均析出大量的次生α相，合金强度明显升高，而塑性较低，断口形貌中出现明显二次裂纹。     

不同退火工艺对TC10钛合金组织与冲击性能的研究

对TC10钛合金进行不同工艺的退火处理，通过扫描电子显微镜（SEM）、X射线衍射仪（XRD）、透射电子显微镜(TEM)以及冲击性能测试，研究经不同退火工艺处理后，该合金微观组织与冲击性能的关系。结果表明：经单重退火处理后，组织由初生α相（αp）与次生α相（αs）构成，证实并无α"相与α"相析出，经双重退火处理后，αp相几乎不变，αs相转变为粗片层αs相与细片层αs相；合金经单重退火处理后的冲击性能总体高于双重退火，经两相区温度加热后的冲击性能高于单相区；在两种退火工艺中，当加热温度为两相区时，断口微观形貌主要由等轴状韧窝构成，当加热温度为单相区时，断口微观形貌以岩石状形貌为主，并有较浅的小韧窝分布在表面。     

韩国铝箔毛料和国产铝箔毛料的比较研究

采用光学显微镜、电子显微镜、Ｘ－ 射线衍射仪等手段比较研究了两批韩国铝箔毛料和五批国产铝箔毛料的显微组织。研究表明,进口毛料和国产毛料中化合物相的类型有较大不同。进口料中化合物相以α（ＦｅＳｉＡｌ）和β（ＦｅＳｉＡｌ） 相为主,而国产毛料中化合物相以ＦｅＡｌ３ 和α（ＦｅＳｉＡｌ） 相为主;进口毛料中固溶的硅含量较低,但晶粒尺寸较大。分析了固溶硅含量、Ｆｅ／Ｓｉ 比和晶粒尺寸等对铝箔轧制性能的影响及针孔增多的原因。     

蚀坑法研究微量Ce及退火对高纯铝箔立方织构的影响

用蚀坑法研究了不同热处理工艺以及Ce含量对铝箔立方织构的影响，结果表明：Ce含量较高时，中间退火300℃ 2h和成品退火150℃ 3h 540℃ 1h条件下，立方织构含量最高，分布均匀；Ce含量较低时，在390℃ 2h中间退火和150℃ 3h 540℃ 1h成品退火条件下，立方织构含量较高；在一次冷轧前进行400℃ 2h退火样品的立方织构含量高于未退火的样品。对比发现，Ce含量高的样品，其立方织构的含量也高。     

分级退火对高纯铝箔再结晶织构的影响

采用晶体取向分布函数（ODF）,极图和TEM分析了高纯铝箔在不同的分级退火工艺过程中再结晶结构的演变,研究结果表明：高纯铝的变形结构主要由S取向组成,另含有少量的Cu织构和Bs织构,2级退火箔材中立方织构含量高于3级退火的;其中在200度低温退火时在亚晶界形成立方核心,并沿亚晶界析出含铁化合物,520℃高温退火后立方织构取向密度最大,R织构含量最少,在250℃低温退火时,形成复大角亚晶界,铁固溶在铝基体中,520℃高温退火后铁在晶内析出,立方织构减少,R取向增强。     

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。