铝合金熔炼中的加Zr方法

Zr是目前铝合金中十分重要的合金化元素之一，对铝合金的许多性能有良好的影响。铝合金熔炼中的加Zr方法通常有三种：化合物法(K2ZrF6)，中间合金法(Al-Zr、Mg-Zr合金)和晶核播种法(用Al-Zr丝材插入流槽熔体内)。现有方法往铝合金熔体中加Zr各有利弊，必须从实际情况出发进行选择。应该开发Zr添加剂，若能投入工业性使用，似乎是一种最佳的加Zr方法。     

汽车板用铝合金材料的研究

以高纯度铝基材(Fe添加量为0.03wt%,Si添加量为0.02wt%)为主要原料,以高纯Zn、Mg、Cu以及Zr为添加剂原料研制汽车板用铝合金。探讨了添加不同量Zr元素对汽车板用铝合金材料性能的影响。结果表明:在铝合金基材中添加0.04%Zr元素,并在425℃下进行退火处理,可制备出性能优良的汽车板用铝合金材料。所制备的汽车板用铝合金材料的弯曲强度为590 MPa,伸长率为19.1%,磨损量为0.00128 g。合适的退火温度以及添加适量的Zr元素有助于细化铝合金材料的微观组织。     

微量锆对架空铝合金导线耐热性和导电性的影响

含0．12％Zr与不含Zr的铝合金棒材，经530℃×1．5h固溶处理和250℃×48h时效处理，再经70％的冷拔加工成φ4．5mm的线材。试验结果表明，前者的耐热性比后者有明显的提高，而导电性降低有限。本文着重对微量Zr合金化对铝合金导线性能产生影响的原因进行了探讨。     

含过渡金属添加剂的Al—Cu—Mg系合金的超塑性

在一定的温度-速度条件下,一系列工业铝合金中均呈现出超塑性效应,其中含Zr(Супгал合金)和Mn(1201合金)添加剂的Al-Cu系以及含Mn和Zr添加剂的Al-Mg系合金最为明显.同时,在文献中象Al-Cu-Mg(п16型合金)这样一科重要合金系的超塑性的研究实际上尚未遇见. 本文研究了含Zr和Sc过渡金属添加剂的16型合金超塑性产生的、条件.     

5182铝合金铸态组织及性能的研究

通过比较不同细化方法细化的Ti含量相同的5182铝合金的微观组织及性能，得出5182铝合金组织及性能达到最优时的细化元素的种类及含量。研究发现，细晶铝锭＋0．25％Zr的晶粒细化能力接近于Al-5Ti-1B中间合金，同时制得的5182铝合金的硬度也是最大的。细晶铝锭＋0．16％La、细晶铝锭＋0．20％RE的晶粒细化能力虽不及Al～5Ti-1B和GRAl＋0．25％Zr，但可使析出相球化。均匀化处理使5182铝合金中晶界和二次枝晶间析出物发生球化。     

稀土金属对铝和Al—Cu—Mn系合金再结晶温度和性能的影响

为了改善铝及铝合金的性能,广泛采用一系列过渡金属(Mn、Ti、Zr、Cr等)添加剂。关于属于元素周期表中ⅢA族元素的过渡金属(Sc、Y、La和镧系元素)对铝及铝合金性能和组织的影响尚研究得还不够充分。有些稀     

含锆铝合金的力学性能和强化机理

研究了高强铝合金的力学性能与Zr含量的关系，计算了合金的各种强化因素值。研究发现：合金的抗拉强度巩和屈服强度如σ0.2均随Zr含量的增加而增大，增幅分别达到11．8％和12．6％；合金延伸率δ在Zr添加量不高时随Zr含量的增加而增大，在Zr含量为0．06％时出现峰值，随后合金延伸率δ逐渐稳定在8％左右。结合合金显微特征，合金强化机理主要包括晶粒细化、颗粒弥散强化及形变强化，在Zr含量为0．16％的合金中相应的强化值分别为21.35和14MPa.     

Sc、Zr复合添加对7085铝合金组织与性能的影响

通过金相显微镜、背散射电子衍射(EBSD)和拉伸力学测试,研究了Sc和Zr元素对7085铝合金组织与性能的影响。结果表明,Sc、Zr具有很强的晶粒细化效果,添加Zr可使铸态晶粒尺寸减小46.7%,添加Sc可减小51.4%,复合添加Sc、Zr效果最佳可减小58.1%。同时,Sc、Zr在合金中会生成Al3Sc和Al3Zr,具有很强的抑制再结晶作用。经轧制、固溶时效后,未添加Sc、Zr的合金会完全再结晶,仅添加Zr的合金再结晶程度为60%,添加Sc和Sc、Zr复合添加的合金再结晶程度非常低,仅约为5%。因此,复合添加Sc、Zr可大幅提高合金的力学性能,在相同工艺条件下,其抗拉强度达606 MPa,比未添加Sc、Zr的合金提高17.6%。     

电解加钛对6063铝合金的晶粒细化效果

向铝电解槽中加入少量的二氧化钍，可生产含少量钍的电解低钍铝合金锭。本文用电解低钍铝合金锭配置6063变形铝合金，研究了这种加钍方式对6063铝合金的晶粒细化效果及细化机理．并与铝钍中间合金．对6063铝合金的细化效果做了对比。结果表明，电解加钍的细化效果优于用铝钍中间合金加钍的细化效果。且随保温时间的延长。有更好的抗晶粒细化衰退效果。用电解低钍铝合金配置6063铝合金是完全可行的，用电解的方法加入二氧化钍是一种质优价廉的新方法。     

压铸高强韧Al-Cu系合金的组织性能及热处理探讨

为了弥补目前压铸铝合金强韧性不足，进行了高强韧Al-Cu系合金的压铸及热处理的试探性研究．在ZL201的基础上．添加合金化元素B、Zr、V等．改善合金的铸造性能，进行压铸成形试验。试验研究发现压铸大大细化了合金的微观组织．铸态性能较金属型高，再经低温时效后合金强度达到一般高强压铸铝合金的水平．但塑性较之提高20％以上。     

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).     

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.     

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.     

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。