氢镍AA充电电池

试验由国际消费者研究及试验组织(International Concumer Research ＆ Testing,ICRT)统筹,于荷兰测试。现将香港选购的6款镍氢充电电池参加这次国际联合测试的比较结果提供给读者。     

动态布流平面凝固铸造AA1070/AA7050合金

提出了一种新的用于大尺寸复层铸锭平面凝固铸造的布流系统,并使用软件FLUENT对铸造过程中分流方式对温度场的影响进行了模拟分析,模拟结果表明,使用动态布流时熔体温度的均匀性显著优于定口布流,因而可实现凝固时固/液界面在上升过程中保持平坦。使用动态布流平面凝固铸造方法实现了1070/7050大尺寸双层铝合金的铸造复合,铸造结果表明,复合铸锭中两种铝合金的界面清晰平直,无气孔夹杂等缺陷,实现了冶金结合并存在元素扩散层;7050侧金相组织均匀,厚度方向上无明显宏观偏析。     

何为AA石墨?

<正>韩国科学技术研究院的研究小组成功研发出一种具有半导体属性的AA型石墨。石墨是由石墨烯一层层叠加而成,根据叠加方式可分为AA石墨和AB石墨,AA石墨因为能量不稳定因此在自然界中不存在。研究小组将石墨烯粉末在一定条件下热处理后将粉末以类似AA型的方式重新组合,这种新的石墨被命名为AA石墨。上述成果已经通过X光和高清晰显微镜分析计算后获得     

Recrystallization kinetics of Al–Mg alloys AA 5056 and AA 5083 after hot deformation

Abstract

Slabs of two commercial Al–Mg alloys were hot rolled on a laboratory mill. A wide range of processing parameters was used in the experimental design and the effect of those parameters on the annealing kinetics was established. The effects of each parameter are described by simple empirical relationships. The recrystallization time required for a given volume fraction recrystallized was found to decrease with increasing total hot strain and with decreasing initial grain size. The recrystallization time also decreased with increasing temperature compensated strain rate. The annealing temperature also has a profound effect. Empirical relationships incorporating all the process variables are presented, and it is shown that the alloy AA 5056 recrystallizes more readily than does alloy AA 5083. It is concluded that this observation arises because of the larger volume fraction of precipitates present in the homogenized 5083 alloy.

MST/357     

Thermo-mechanical and microstructural issues in dissimilar friction stir welding of AA5086–AA6061

In this research, thermo-mechanical behavior and microstructural events in dissimilar friction stir welding of AA6061-T6 and AA5086-O have been evaluated. The thermo-mechanical responses of materials during the process have been predicted employing a three-dimensional model together with a finite element software, ABAQUS. Then, mechanical properties and microstructures of the weld zone were studied with the aid of experimental observations and model predictions. It is found that the mixing of material in the weld nugget is performed more efficiently when AA5086 is in the advancing side and also the temperature field is distributed asymmetrically resulting in larger thermally affected region in the AA6061 side. Besides, the microstructural studies shows that the microstructures of stirred zone consist of fine equiaxed grains where finer grains are produced in AA6061 side compared to AA5086 side.     

能撕开的AA制账单

跟同学、同事一起出去吃饭，一般都是各付各的AA制，但大家吃的餐往往都不是一个价，于是最后结账时总是要进行复杂无比的运算以保证精确AA制，那么这款账崩身十则完全解决了这个问题。     

A study on microstructures and residual stress distributions in dissimilar friction-stir welding of AA5086–AA6061

Dissimilar friction stir welds of aluminum alloys AA5086 in annealed and AA6061 in T6 temper conditions were investigated in terms of residual stress, grain structure and precipitation distribution in different zones of the welded joints. Optical metallography and transmission electron microscopy were used to characterize microstructures of different zones of the welds. In addition, residual stress profile and local mechanical properties of different zones were evaluated employing X-ray diffraction method and digital image correlation technique. It was found that softening in the AA6061-T6 side occurs in regions with weld peak temperature higher than 300 °C. The micro-hardness profile results and TEM investigations also showed that thermo-mechanical affected zone of AA6061 side with large plate-shaped β precipitates is the softest region of the joints in AA6061 side. Furthermore, residual stress distribution within the samples is not directly dependent on the local mechanical properties of different zones of the joints.     

AA改性纳米CaCO3/聚丙烯的力学性能

用熔融挤出法制备了丙烯酸(AA)改性纳米CaCO3／PP母料及复合材料，系统研究了两种粒径的纳米CaCO3、单体AA和引发剂DCP的用量，以及制备母料的不同基体对纳米CaCO3／PP复合材料力学性能的影响。结果表明纳米CaCO3／PP复合材料的力学性能高于微米CaCO3／PP复合材料，纳米CaCO3对PP有增强增韧作用。在制备母料过程中加入AA，有助于进一步提高纳米CaCO3／PP复合材料的力学性能。加入少量DCP也有利于提高复合材料的力学性能。制备母料的基体为粉状PP的力学性能高于粒状PP。     

Lüders elongation in AI-Mg alloy AA5182

Abstract

Aluminium-magnesium alloys such as AA5182 exhibit a yield point elongation, or Lüders strain, when deformed in the annealed O temper, and the extent of the Lüders strain is a function of processing history and the deformation conditions. The yield point effect is usually attributed to Mg solute pinning, but is has been appreciated for some time that factors such as grain size, and cooling rate from the annealing temperature, affect the Lüders strain, and it has not been clear how this behaviour is consistent with solute pinning. In this paper it is shown that the presence, or absence of Lüders effect (Lüdering) is related to the grain boundary structure, and processing which results in a high concentration of grain boundary dislocations removes the yield point effect, whereas fabrication routes which produce defect free bondaries result in a Lüders strain. The extent of the Lüders strain, and its dependence on grain size and deformation conditions, is reasonably consistent with some recent models of propagative plastic instabilities.     

PP－g－AA的制备和表征

用熔融接枝方法制备了聚丙烯－ｇ－丙烯酸（ＰＰ－ｇ－ＡＡ）。用光电子能谱，广角Ｘ射线衍射，红外光谱和化学滴定方法对接枝物进行了定性和定量表征。讨论了单体和引发剂浓度对接枝率的影响，确定了用红外光谱法测定接枝物含量的经验公式     

GB4706.12中附录AA浅谈(英文)

There are many factors that affect the safety of home appliance,of which the difference in building units may produce relatively considerable in fluence over the safety of home appliance.The building in Europe is basically used by a single family,     

PP—g—AA的制备和表征

用熔融接枝方法制备了聚丙烯－ｇ－丙烯酸，用光电子能谱，广角Ｘ射线衍射，红外光谱和化学滴定对接枝物进行了定性和定量表征。讨论了单体和引发剂浓度对接枝率的影响，确定了用红外光谱法测定接枝物含量的经验公式。     

AA3流动注射测定地表水中阴离子合成洗涤剂

用新型的AA3流动注射（妓萃取圈）对地表水中的阴离子合成洗涤剂进行分析测定,与传统的分析方法相比,该方法具有快速、灵敏度高、检出限低的特点。该方法的分析频率可达20次／小时、检测下限为0．008mg／L,大大提高了实验室自动化程度．     

AA2195铝锂合金的热变形行为

通过Gleeble-3500热模拟实验机上进行热压缩实验,研究了变形温度为400~500℃,应变速率为0.01~10s~(-1)时2195铝锂合金的热变形行为。通过金相显微镜研究了热变形中显微组织的演变。研究结果表明,该合金流变应力随变形温度的升高而降低,随应变速率的提高而增大。该合金流变应力可采用Zener-Hollomon参数来描述,在获得流变应力σ解析表达式中A=7.08018×1012 s~(-1)、α=β/n1=0.01473、n1=5.42929,其热变形激活能为Q=190.27kJ/mol。热加工图表明AA2195铝锂合金适宜加工区为400~430,442~473℃,应变速率为0.01~0.2s~(-1)以及温度范围为477~500℃,应变速率为0.01~0.3s~(-1)的区域。     

Effect of welding parameters on mechanical and microstructural properties of dissimilar AA6082–AA2024 joints produced by friction stir welding

The effect of processing parameters on the mechanical and microstructural properties of dissimilar AA6082–AA2024 joints produced by friction stir welding was analysed in this study. Different samples were produced by varying the advancing speeds of the tool as 80 and 115 mm/min and by varying the alloy positioned on the advancing side of the tool. In all the experiments the rotating speed is fixed at 1600 RPM. All the welds were produced perpendicularly to the rolling direction for both the alloys. Microhardness (HV) and tensile tests performed at room temperature were used to evaluate the mechanical properties of the joints. The mechanical tests were performed on the joints previously subjected to annealing at 250 °C for 1 h. For the fatigue tests, a resonant electromechanical testing machine was employed under constant loading control up to 250 Hz sine wave loading. The fatigue tests were conducted in the axial total stress–amplitude control mode, with R = σ_min/σ_max = 0.1. In order to analyse the microstructural evolution of the material, the welds’ cross-sections were observed optically and SEM observations were made of the fracture surfaces.     

AN/AA共聚物热解反应表观活化能的计算

采用差示扫描量热法,研究了丙烯腈（AN）／丙烯酸（AA）共聚物在空气中的低温热解反应,利用Kissinger方法,计算了AN／AA共聚物热解反应的表现活化能,讨论了不同聚合工艺对共聚物热解反应表现活化能的影响。结果表明,随混合溶剂中二甲基亚砜含量的增加,共聚物热解反应表现活化能增加;随共聚单体AA含量的增加,共聚物热解反应表现活化能降低;当AA与AN质量配比高于5／95后,共聚物热解反应表观活化能变化不大;随反应温度增加,共聚物热解反应表现活化能增加。     

微波辐射海带接枝AA/AM合成高吸水树脂

以N,N-亚甲基双丙烯酰胺为交联剂,通过微波辐射法制备了海带接枝丙烯酸(AA)和丙稀酰胺(AM)高吸水树脂。讨论了单体配比、丙烯酸中和度、交联剂用量及引发剂用量、辐射时间等因素对吸水性能的影响,采用响应面分析法优化合成条件,并用红外光谱对产物进行了表征。研究结果表明:当海带用量35%,AM∶AA比例为20%,引发剂用量8.1%,交联剂用量0.052%,NaOH的中和度为79.3%,辐射时间45s时,制备的高吸水树脂的吸自来水倍率达176.62g/g。     

AA5083铝合金在海水中的腐蚀行为研究

采用电化学工作站研究了AA5083铝合金在海水中的极化曲线、点蚀电位、交流阻抗等性能,通过高分辨率数码显微镜、扫描电镜等表征手段对AA5083铝合金腐蚀前后的表面形貌进行了研究。研究结果表明:AA5083铝合金在静态海水中的腐蚀以点腐蚀为主,浸泡初期阻抗由容抗和感抗组成,腐蚀电位随着浸泡时间的延长不断负移,耐腐蚀性降低,点腐蚀坑越来越多,并且点腐蚀坑不断增大加深,在试板表面中间区域形成半球状点腐蚀坑,腐蚀达到一定程度后,出现Warburg阻抗,腐蚀电位逐渐稳定在-0.58V。     

改善AA1100空调箔强韧性生产工艺的研究

研究了改善AA1100空调箔强韧性的生产工艺.结果表明,采用合理的均匀化工艺,230-260℃×1h成品退火,并尽可能提高退火加热速度,有助于AA1100空调箔达到最佳的强韧性效果.同时,对空调箔的强韧化机理进行了探讨.     

AA1060–DP600板材电磁脉冲连接工艺研究

目的 基于平板线圈对AA1060–DP600板材电磁脉冲连接过程进行数值模拟与工艺实验,探索线圈匝数、搭接区宽度、搭接间隙和放电电压等4个参数对连接接头质量的影响。方法 基于有限元分析软件(LS–DYNA),建立尺寸参数为80 mm×40 mm×1 mm的AA1060–DP600板材电磁脉冲连接有限元模型;基于平板线圈搭接实验装置进行工艺实验,采用电子万能实验机、金相显微镜对接头拉伸性能进行测试并观察其微观形貌,结合模拟与工艺实验的结果分析各个参数对接头质量的影响。结果 随平板跑道线圈匝数由1匝增至6匝,飞板与基板碰撞速度先升后降,在3匝时达到最大值;搭接间隙过大(2.5 mm)或过小(1.5 mm)都会使碰撞速度下降,进而使接头强度下降;碰撞速度和接头强度与搭接区宽度和放电电压成正相关,放电电压在9 kV及以上时更易实现连接;连接接头界面总体趋于平直,部分区域出现小波峰大波长的波形。结论 以拉伸性能最优为标准,最优的工艺参数为线圈匝数3匝、搭接间隙2 mm、搭接区宽度25 mm、放电电压11 kV,此条件下试件可承受的最大载荷为2.33 kN,达到母材AA1060的75%。