棕刚玉中二氧化钛的高灵敏度光度分析

本文报道了二氧化钛与新显色剂对溴偶氮羧-M的高灵敏显色反应的研究结果。以磺基水扬酸掩蔽Fe3 ,A l3 ,在pH2.1-3.6时新显色剂对溴偶氮羧-M与钛在室温下形成稳定的β型配合物。其最大吸收波长为715nm,表观摩尔吸光系数ε715=1.2×105L.mol-1.cm-1,TiO2含量在0-53μg/50m l范围内服从比耳定律。配合物的组成比为Ti:R=1:2。用于棕刚玉中二氧化钛的测定,结果满意。     

Characterizing the physical and chemical properties of aluminum dross

In this article, the results of an investigation of granular and compact aluminum drosses are reported. The bulk density of granular drosses was determined according to DIN 52110-B, while DIN 52102-RE-VA was applied to compact drosses. The salt contents of the drosses were measured by applying the leaching test DIN 38414-S4; the metal contents by the salt-melting process were measured on a laboratory scale. In addition to the density data, the particle-size analysis, the distribution of elements in the different fractions, composition, metal content of recovered alloys, and gas evolution were compiled in a dross identity card characterizing each dross and simplifying the preanalysis for recovery.     

The recycling of standard quality wrought aluminum alloys from low-grade contaminated scrap

In recent decades an increasingly large fraction of the world’s wrought aluminum alloys supply has come from the aluminum scrap recovered from industrial waste and discarded post-consumer items. However, replacing even a minor part of primary aluminum in wrought alloys with recycled counterpart originated from lower grades of scrap (typically scrap contaminated with various non-metallic impurities) without influencing the quality of the allay is very demanding from a metallurgical point of view. This article discusses the two approaches for achieving the requested chemical composition of wrought alloys made from recycled aluminum: (i) before melting, by combining the appropriate qualities and quantities of scrap, primary aluminum, and the alloying elements and (ii) during melting, by diluting impurity content with primary aluminum to the needed level and adding, at the same time, the necessary amount of alloying elements for achieving their standard concentration in diluted melts.     

铸造A356铝合金的低周疲劳行为

研究不同加钛方式和钛含量对铸造A356铝合金常温低周疲劳行为的影响,分析合金疲劳断口的形貌特征.结果表明:4种A356合金均表现出明显的循环硬化行为,但Ti含量(质量分数)为0.14%的合金比Ti含量为0.10%的合金具有更高的循环硬化率.在低应变时,加钛方式对合金的循环硬化影响相近;而在高应变时,电解加钛A356合金...     

Research on Standard Flow for materials life cycle assessment

For the sake of objectivity of the interpretation in life cycle assessment (LCA), the concept and the design proposal of Standard Flow were put forward. Standard Flow was defined as the collection of related environmental load parameters that represent the specific development degree of certain industrial process(es) by the function unit. A novel methodological approach called the Standard Flow Comparing, was developed for LCA. The indicator for potential of process improvement and its weighting factor were derived. To a certain degree the problem of the identification and selection of process development objects in LCA was solved. The concept of Standard Flow and the method of Standard Flow Comparing are introduced, formulized and analyzed.     

铝灰中铝资源回收工艺现状与展望

铝灰是铝工亚一种重要的副产品,其中的铝含量约占铝生产使用过程中总损失量的1%～12%.回收铝灰中的铝资源能降低成本、保护环境、节约能源和提高资源利用率,有着巨大的经济和社会效益.本文总结了铝灰的来源、分类和组成,综述了铝灰中回收金属铝的回收工艺和利用铝灰合成材料工艺,展望了铝灰回收工艺的发展前景,提出了相关建议.     

Effect of the hardness on the service life of die-casting molds for aluminum alloys

Conclusions The service life of die-casting molds for aluminum alloys is greatest for steel 4Kh5MFS after quenching from 1010–1040°C and tempering at 560–570°C to hardness HRC 49–50.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 66–67, October, 1978.     

The anisotropy of aluminum and aluminum alloys

The anisotropy of textured aluminum is approximated by a yield criterion with an exponent of eight. The use of this criterion in metal-forming analyses has improved the understanding of the formability of aluminum and other metals. The effect of anisotropy on the limiting drawing ratio in cupping is less than that expected from the quadratic Hill yield criterion and the effect of texture on forming limit diagrams is negligible. A method of predicting the effect of strain-path changes on forming limit curves of aluminum alloy sheets has proven to agree with experiments.     

Simulation for microstructure evolution of Al-Si alloys in solidification process

The numerical simulation for microstructure evolution of Al-Si alloy in solidification process is carried out with phase field model. The phase field model, solution algorithm and the program of dendrite growth are introduced. The definition of initial condition, boundary condition and the stability condition of differential format are all included. The simulation results show that the evolution of dendrite morphology is as follows： the initial circle nucleus transforms to the rectangle one firstly, then its corners develop to the four trunks and from which the secondary side branches are generated and even the third side branches are produced from secondary ones. The dendrite tip radius decreases quickly at the initial stage and changes slowly at the late stage, which is mainly due to the fact that more and more side branches appear and grow up. The comparisons of dendrite morphology between simulated results and investigations by others are also presented. It is proved that the dendrite morphologies are similar in trunks and arms growth, so the developed phase field program is accurate.     

Filtering and fluxing processes for aluminum alloys

… two processes that have been developed for improving the quality of molten aluminum alloys before casting.     

铝灰渣中AlN水解行为及其多元非线性回归分析

通过对铝灰渣水解反应过程中组分及其含量变化的研究,提出铝灰渣中AlN含量的修正公式;根据AlN含量和悬浊液pH值的测定,考察时间、温度、转速等水解参数对AlN水解速率的影响并对其进行多元非线性回归分析。结果表明:升高温度能降低铝灰渣中AlN含量并降低悬浊液pH值;延长时间可有效促进AlN的水解,同时在2h内悬浊液pH值迅速提升至高位;转速对AlN水解速率和悬浊液pH值无明显影响。总体而言,AlN含量比悬浊液pH值更能客观表征铝灰渣中AlN水解速率。对水解参数及修正后铝灰渣中AlN含量进行多元非线性回归分析并二次简化,发现理论值与实验值相对误差≤±8.65%。     

Al-Si和Al-Si-Sc合金的界面能各向异性的研究

平衡液滴法(Equilibrium shape measurement)是一种确定晶体-熔体界面能各向异性参数的有效方法。本文利用平衡液滴法测量单相固体中夹带的平衡液滴的形状,得到了Al-Si和Al-Si-Sc合金的界面能各向异性参数计算值。通过定向凝固方法制备Al-2wt.%Si和Al-2wt.%Si-0.2wt.%Sc合金杆状试样,使用光学显微镜表征Al-2wt.%Si和Al-2wt.%Si-0.2wt.%Sc合金内部液滴手工连续磨样抛光后多个二维截面形状,计算了二维界面能各向异性参数的大小。利用FIB(Focused ion beam)技术连续切割了Al-2wt.%Si合金内部液滴,并用Image-J软件重构液滴三维形状,获得了三维界面能各向异性参数值以及三维界面能分布和界面刚度的分布。在此基础上,讨论了平衡温度和Sc元素对界面能各向异性参数的影响。     

过氧化氢比色法测定棕刚玉中二氧化钛含量的不确定度评定

本文对过氧化氢比色法测量棕刚玉中二氧化钛含量的不确定度进行了评定,分析了测量过程中不确定度的主要来源,如测量重复性、溶液浓度、溶液体积、试样溶液定容体积、分取溶液体积等,并对各不确定度分量进行了量化计算。结果表明:过氧化氢光度法测定棕刚玉中二氧化钛含量不确定度的最主要来源是测量溶液浓度所引入的不确定度,其次是测量方法重复性的不确定度。     

3C产品塑料与铝合金外壳材料的生命周期评价

分析3C产品塑料与铝合金外壳材料的生命周期评价,探讨两种材料作为3C产品外壳材料的利弊.据数据资料分析可知:在材料的性能方面,与塑料相比,铝合金具有高强度、导热性好、易加工成形和电磁屏蔽等优点,可以满足3C产品轻、薄、小的发展要求;在环境相容性方面,虽铝合金能源消耗较高,但资源消耗、水污染、大气污染、土壤污染及材料的回收再利用等方面都优于塑料.铝合金用作3C产品外壳材料更利于环保,符合走可持续发展道路的要求.     

Forming and bonding techniques for high-strength aluminum alloys

This article highlights the continued preference for aluminum as a structural material for aircraft, where demands for high performance coupled with the need for weight reduction have led to the use of high-strength aluminum alloys. The ever-increasing demand for a high level of integration of complex structural components calls for the development of appropriate manufacturing processes. As an example, superplastic forming is discussed, combined with innovative bonding techniques such as diffusion bonding and adhesive spot welding.     

喷射沉积高硅铝合金显微组织及形成机理

研究了喷射沉积Ａｌ－２０％Ｓｉ及Ａｌ－３０％Ｓｉ合金坯料的显微组织及形成机理。结果表明,两种合金的喷射沉积态组织为细小的团块状Ｓｉ均匀地分布于基体α上,没有共晶组织出现。形成该组织特征的机理是由于在沉积阶段凝固过程中合金发生了离异共晶,在雾化阶段大的冷却速度下形成的大量Ｓｉ相核心以及在沉积阶段相对较低的冷却速度为这一过程提供了动力学条件。通过自行设计的沉积阶段凝固的模拟实验,对这一机理进行了验证;