脉冲电解及其国内外研究概况

脉冲电解可以调解电流密度、电流的通断时间、脉冲频率等多个参数,为控制金属沉积层的质量和沉积速度提供了有力的手段.介绍了近年来国内外有关脉冲电解的主要研究方向.     

Modeling of Plate-like Precipitates in Aluminum Alloys—Comparison between Phase Field and Cellular Automaton Methods

This report compares two approaches for simulating microstructure evolution of plate-like precipitates during artificial ageing of aluminum alloys: the phase field and the cellular automaton methods. Although both methods are based on thermodynamics, they handle the kinetics in quite different ways, each with its own advantages and disadvantages. Both methods were applied to the growth of semi-coherent plate-like precipitates in Al-4 wt% Cu. Good agreement is found between the results of these two models, as well as experiments. A combination of these two methods would provide a novel approach that is both physically sound and computationally effective for the application of precipitation modeling.     

神经网络低温铝电解电流效率预报模型

本文研究基于神经网络的低温铝电解电流效率预报模型。实验样本采自用Ｎａ３ＡｌＦ６－ＡｌＦ３－ＣａＦ３－ＭｇＦ２－ＬｉＦ－Ａｌ２Ｏ３体系中低分子比电解质所进行的电解实验，从实验样本中随机抽学习样本训练网络，建立电流效率与影响它的电解工艺参数包括熔体成分，电解温度，阴极电流密度和极距之间的关系模型，尔后用剩余的实验样本检验模型精度，结果表明；该模型精度高，具有良好的预报效果。神经网络作为一种新颖的拟合预     

A MODEL OF BUTTERFLY CATASTROPHE FOR ANODE EFFECT IN ALUMINA ELECTROLYSIS

A model of butterfly catastrophe is confirmed based on the matching and fitting the previousexperimental data from alumina electrolysis when anode effect occurs.The complicatedbehaviour of the cryolite-alumina melt system with varying parameters could be generallydescribed by this model.Therefore,the anode effect and its occurrence may be thoroughlyunderstood.     

赵家沟金矿载金炭解吸电解设备技术改造

详细介绍了辽宁省彰武县赵家沟金矿解吸电解设备技术改造内容及调试情况,并对改造前后的技术经济指标进行了对比。     

Additional microstructural analysis on the samples examined in the paper ‘Are high resolution resistometric methods really useful for the early detection of electromigration damage?’

In a previous paper (A. Scorzoni, S. Franceschini, R. Balboni, M. Impronta, I. De Munari, and F. Fantini, Are high resolution resistometric methods really useful for the early detection of electromigration damage? Microelectr. Reliab. 1997;37(10/11):1479–1482), we reported largely different electromigration lifetimes and different high resolution early resistance changes measured on two nominally identical lots of 4 μm wide lines tested at moderately accelerated stress conditions. A microstructural analysis on unstressed samples was performed in order to detect the reason which induced these differences. The analysis confirmed a major defectivity of the lot with shorter lifetime: we detected the presence of TiAl₃ precipitates at the interface between the Al–Cu and the Ti-based metal barrier. This was not easily detectable by means of simple visual inspection. These additional findings confirm that a quick electrical detection of the metallization quality could be feasible by means of high resolution resistance measurements without the need of time-consuming direct examination of production lots.     

Colloidal flocculation of micellar solutions of anionic surfactants

Micellar solutions of anionic surfactants usually precipitate in the presence of cations, following a mechanism by which initially cations bind themselves to the micellar surface until saturation is achieved. At higher cation concentrations, unbound cations precipitate with surfactant monomers. In a few cases cations, and especially Al³⁺, cause surfactant micelles to flocculate. These flocs have properties as adsorbents of acidic organic compounds, which might be used in water treatment processes. Both α-olefinsulfonates C₁₄−C₁₆, and laurylsulfate micellar solutions are fast flocculation colloidal systems in the presence of Al³⁺.     

Micro-end-milling-I. Wear and breakage

Unpredictable tool life and premature tool failure are major problems in micro-machining. In this study, the failure mechanisms of micro-end-mills were studied during the machining of aluminum, graphite electrodes and mild steel workpieces. Hundreds of machining operations were performed, and the pictures of cutting edges were taken with a scanning electron microscope to identify fatigue and extensive stress-related failure mechanisms. Also, the cutting force variation was monitored, i.e. the relationship between the utilization-related changes at the tool structure (wear), and the outcomes (increasing cutting force which means raising stress on the tiny shaft). Inspection of the cutting force variation patterns of large numbers of micro-end-mills indicated that tool failure occurs with chip clogging, fatigue and wear-related excessive stress depending on the characteristics of the workpiece. Two tool breakage prediction methods were developed by considering the variation of the static part of the feed direction cutting force. These methods used segmental averages and wavelet transformation coefficients. The accuracy of the proposed approaches were tested with experimental data and the agreement between the predictions and actual observations are reported.     

高锰铝青铜合金强韧性的研究

研究了Ａｌ,Ｍｎ含量,Ａｌ当量及浇注温度对高锰铝青铜合金强韧性的影响,优选了合适的合金成分,并分析了Ａｌ当量与力学性能之间的关系。     

铝基复合材料的腐蚀研究现状

总结了近年来铝基复合材料腐蚀研究的有关文献,分析了碳化硅,碳纤维,三氧化二铝和硼纤维等增强物对铝金属基体腐蚀的影响,一般而言,铝基复合材料比基体铝合金更容易产生腐蚀。