硼对电解低钛铝基合金微观组织的影响

研究了Al-B中间合金对工业纯铝和电解低钛铝基合金微观组织的影响.结果表明,硼对纯铝晶粒细化作用较弱;对于电解低钛铝基合金而言,由于在电解过程加入的微量钛的作用,其晶粒已经得到明显细化,且随着钛含量的增加,晶粒细化效果不断加强.向电解低钛铝基合金按Ti:B=5:1的重量比再熔配加入Al-B中间合金,可明显改善电解加钛的晶粒细化作用,特别是在钛含量较低时作用更加明显,随着Al-B中间合金添加量的增加,硼的作用逐渐减弱,最终与不加硼的电解低钛铝基合金的细化效果相当.     

稀土在铝合金表面处理中的应用及研究进展

评述了稀土在铝合金表面处理中的应用及研究进展,尤其是铝合金稀土表面转化膜技术和稀土对铝合金阳极氧化的影响两方面.稀土表面转化膜能够提高铝合金的耐蚀性能,工艺以化学浸泡为主;稀土对铝合金阳极氧化是有益的:它使铝合金接受极化的能力增强,同时提高氧化膜的抗蚀性.因此,稀土应用于铝合金表面处理具有良好的发展前景.     

Evaluation of the Corrosion Resistance of Fe–Al–Cr Alloys in Simulated Low NO x Environments

Due to their excellent corrosion resistance, iron aluminum alloys are currently being considered for use as weld claddings in fossil fuel fired power plants. The susceptibility to hydrogen cracking of these alloys at higher aluminum concentrations has led researchers to examine the effect of chromium additions on the corrosion resistance of lower aluminum alloys. In this work, three iron aluminum alloys were exposed to simulated coal combustion environments at 500 and 700 °C for short (100 h) and long (5000 h) isothermal durations. Scanning electron microscopy was used to analyze the corrosion products. All alloys exhibited excellent corrosion resistance during short term exposures. For longer test times, increasing the aluminum concentration improved alloy corrosion resistance. The addition of chromium to the binary iron aluminum alloy prevented the formation iron sulfide and resulted in slower corrosion kinetics. A general classification of the scales developed on these alloys is presented.     

Corrosion Behavior of Aluminum Alloys in the Presence of Hydrogen Sulfide

The corrosion–electrochemical behavior of both carbon steel and aluminum alloys in hydrogen sulfide-bearing mineralized media is considered. An increase in the partial pressure of hydrogen sulfide aggravates the catastrophic breakdown of carbon steel, yet diminishes both the corrosion rate and the localization of corrosion attack on aluminum alloys. An investigation of the nature of the nonstoichiometry of surface oxide films on both carbon steel and aluminum alloys with the use of photoelectric-recombination method, revealed that the films fundamentally differ in semiconductive properties, according to which hydrogen sulfide can either promote or inhibit the corrosion. That is why hydrogen sulfide oppositely affects the corrosion–electrochemical behavior of aluminum alloys and carbon steels.     

轨道车辆铝材的性能及尺寸(1)

铝材在轨道车辆制造中获得了广泛的应用,高速铁路(简称高铁)与磁悬浮列车的车体全是用铝合金制造的,城轨车辆及地铁车辆也有约40％为铝合金的,专用运煤及其他矿产品车辆也可用铝合金制造.制造铝合金轨道车辆的铝材主要有板、带、箔、型、管、棒材与锻件等.板材主要是用5754、5083、5052等铝合金生产,型材主要是用6063、6N01、6082、6061、7003、7N01等铝合金生产,生产锻件的合金有6061、6110A、5083等铝合金.对这些合金材料的力学性能以及欧盟的有关标准进行了介绍.在选择铝合金时应综合考虑强度性能、使用性能、耐用性能、物理性能、可焊接性、成形性能、抗腐蚀性能和成本等因素.全文分为三部分刊出,本篇对生产轨道车辆板材和挤压材的5×××系铝合金进行介绍.     

Development on research of advanced rare-earth aluminum alloy

1　INTRODUCTIONTheeffectofrareearthandtransitionelementsonthealuminumalloyisevidentfortheirspecialelec tronicstructures ,andthishasattractedattentionsofmanyscientists .Inthepast ,theresearchontherareearthaluminumalloyswascarriedoutmainlyonthebasisofassignmentofthespecifictypeandstrategy ,especiallyinChina ,andexplorationsoftheapplica tionoftherareearths (richresourceinChina)inalu minumalloysweremostlyconcentratedontheeffectofmischmetalonsomecommercialaluminumalloys ,whichwasthecertainoffs…     

Stability of the solid solution of scandium in aluminum

In recent years scandium has attracted the attention of researchers as an alloying component of aluminum alloys. Industrial compositions of scandium-alloyed aluminum alloys have been developed with consideration of its various positive effects on the structure and properties of aluminum. The results of an investigation of the kinetics of decomposition of a solid solution of scandium in aluminum are analyzed and generalized. C-curves of the decomposition are presented for aluminum alloys with different contents of Sc, Si, Fe, Mn, Zn. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 15–20, February, 1997.     

Alloying aluminum alloys with scandium and zirconium additives

In recent years Russian specialists have developed industrial weldable aluminum alloys alloyed with a small amount of scandium. Scandium added to existing weldable aluminum alloys improves considerably the set of their operational properties. In addition, the presence of scandium makes it possible to create new materials superior to traditional aluminum alloys. The present paper is devoted to problems of simultaneous alloying of aluminum alloys with scandium and zirconium.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 25 – 30, August, 1996.     

The high-temperature oxidation resistance of iron-silicon-aluminum alloys

Silicon or chromium can be used as an oxygen getter in iron-aluminum alloys to prevent the internal oxidation of aluminum. This suppresses the formation of the iron oxide nodules that tend to destroy binary iron-aluminum alloys during high-temperature oxidation. Alloys of iron containing aluminum and silicon in varying proportions were heated in flowing air for 50 hr at 1093°C. Of the alloys tested, one containing 6% aluminum and 1 % silicon was the most resistant to oxidation.     

电解加钛铝合金的晶粒细化及其制备铝-硅合金的组织和性能

研究了电解加钛的晶粒细化作用,与AlTi和AlTiB细化剂对纯铝的晶粒细化效果进行了比较;对用电解低钛铝合金制备的A356合金和由纯铝制备并用AlTi或AlTiB细化处理的A356合金的组织与性能进行了对比研究;进行了利用工业铝电解槽生产的电解低钛铝合金熔体直接生产A356合金的工业试验。结果表明：电解加钛具有显著的晶粒细化作用,其细化能力与AlTiB的相当,明显优于AlTi中间合金的。在试验室条件下,用电解低钛铝合金制备的A356合金与纯铝制备并用中间合金细化处理的A356合金的拉伸性能相当;将电解低钛铝合金熔体直接用于铝．硅合金的生产是可行的,并具有节约能源,细化处理工艺简单,产品质量良好的特点。     

铝合金热氧化膜研究现状

直接高温热氧化作为一种环保、无污染的铝及铝合金氧化方法,已经得到广泛研究。较为系统的介绍了目前铝及铝合金热氧化的研究现状,阐述了纯铝、铝合金、铝粉末的热氧化层的生长机理、成分和微观结构,展望了今后铝合金直接热氧化方法应用前景和发展方向。     

Effect of Scandium on the Structure and Properties of Aluminum Alloys

It is shown that the addition of scandium considerably influences the structure and properties of aluminum and its alloys. Scandium is the strongest inoculant of the cast grain structure of aluminum alloys, the strongest suppressor of recrystallization, and the strongest hardener (per 0.1% of the additive). The addition of zirconium intensifies and stabilizes the action of scandium. Commercial aluminum alloys alloyed with scandium and zirconium and a technology for fabricating deformed semiproducts from them are presented. The combination of operating properties of scandium-bearing aluminum alloys is substantially superior to that of traditional aluminum alloys.     

6xxx系铝合金表面腐蚀及其防腐的研究现状

6xxx系(Al-Mg-Si)铝合金作为综合性能良好的中强铝合金,因其较小的密度、良好的耐蚀性和成形性等优点,被广泛应用在航空航天、交通运输和建筑机械等领域。然而,该类铝合金在工业应用中依然存在腐蚀问题,造成巨大的经济损失,带来严重的安全隐患。针对这一问题,首先介绍了6xxx系铝合金的腐蚀类型,总结了影响其耐蚀性的影响因素,重点介绍了合金元素对其耐蚀性的影响。已有的研究结果表明:铝合金中的Mg、Si、Cu、Zn等元素显著影响合金的耐蚀性能,过量Si和Cu元素的添加增加了铝合金的晶间腐蚀敏感性;适当地添加过渡族金属元素及稀土元素,可有效改善铝合金的耐蚀性。随后,分析了提高铝合金耐蚀性能的途径,包括改善热处理工艺、优化合金成分及添加复合物等方法,并介绍了几种典型的表面防腐处理工艺,如阳极氧化技术、微弧氧化技术、化学转化膜技术、电镀及化学镀技术。最后总结了以上防护途径存在的一些问题,并指出了耐蚀铝合金的主要发展方向。     

High-Temperature Strength of High-Purity Aluminum Alloyed with Various Elements

A derivatographic method is used to study the high-temperature strength of aluminum with a purity of 99.9999% and its alloys with magnesium, scandium, gadolinium, holmium, barium, and strontium. The degree of oxidation of high-purity aluminum and its alloys is determined depending on the temperature and the hold time. It is shown that the high-temperature strength of aluminum depends on its purity. The heat fastness threshold of high-purity aluminum is 580°C as compared to 475°C of commercial-purity aluminum.     

The recycle of wrought aluminum alloys in Europe

Increasing demand for aluminum-based products and globalization of the aluminum industry have contributed significantly to the higher consumption of aluminum scrap for re-production of wrought aluminum alloys. The recycling of wrought auminum alloys not only fills market demand, but does so economically. It is a well-known fact that recycling wrought aluminum alloys from collected scrap consumes 15 times less energy than producing primary aluminum, and the cost of internal scrap is marginal. This paper examines opportunities for recycling scrap to solve the ongoing problem of raw material shortages for European producers of wrought aluminum alloys.     

A mathematical model to predict the strength of aluminum alloys subjected to precipitation hardening

A number of alloys, notably most of the aluminum alloys, can be heat treated by aging. This aging due to time-dependent precipitation hardening increases the strength and hardness as well as modifying other mechanical properties. Precipitation hardening has been a popular strengthening mechanism for many decades; therefore, extensive information is available in literature about the precipitation-hardening response of various series of aluminum alloys. The age-har dening response of these alloys is usually represented in graphical form as plotted between property changes and aging time for different temperatures. In designing a suitable precipitation-hardening strategy, one can refer to these graphs. However, for automatic control of aging furnaces, as well as for decision making regarding optimal selection of aging conditions (time/temperature combination), it is desirable to express these relationships in a formal mathematical structure. A mathematical model is developed in this article for widely used heat treatable aluminum alloys used in the extrusion industry. This model is a condensed representation of all σ=f(T, t) curves in different series of aluminum alloys, and the parameters of this model characterize the various compositions of the alloys in the series.     

船舶用耐蚀铝合金的研究进展

介绍船舶耐蚀铝合金的应用概况,讨论了船舶用耐蚀铝合金的耐蚀性能,对船舶用耐蚀铝合金的发展方向进行了展望。     

铝合金搅拌摩擦焊接接头组织与性能的研究进展

讨论了铝合金搅拌摩擦焊接接头的组织与缺陷,分析了缺陷产生的原因、危害以及避免缺陷产生的方法;分别阐述了铝合金搅拌摩擦焊接接头性能的研究热点,并指出了目前铝合金搅拌摩擦焊接接头组织与性能研究中存在的问题。     

Tensile properties of some copper- and zinc-based alloys: Effects of strain rate and test temperature

This study analyzes the effects of test temperature and strain rate on the tensile properties of some copper-and zinc-based alloys. The copper-based alloys comprised a leaded-tin and an aluminum bronze, whereas the zinc-based alloys were added with various quantities of aluminum. The aluminum bronze attained maximum room-temperature tensile strength, whereas that of the leaded-tin bronze was the least. Among the zinc-based alloys, the one comprising 27.5 mass% aluminum exhibited superior tensile strength, followed by those alloyed with 11.5, 37.5, and 47.5 mass% aluminum in a descending order. Increasing strain rate tended to improve the tensile strength of the alloys. Tensile strength was reduced with an increase in test temperature irrespective of the alloy composition. The aluminum bronze possessed maximum strength regardless of temperature. The leaded-tin bronze attained least strength property at low temperatures, whereas higher test temperatures led to superior strength than the zinc-based alloys. The temperature sensitivity of the strength of the zinc-based alloys decreased with their aluminum content. Tensile elongation of the alloys tended to increase with an increase in strain rate and test temperature. Leaded-tin bronze was least affected in either case. The alloy also attained least elongation irrespective of test conditions. The aluminum bronze showed maximum elongation, at least at high strain rates. In the case of the zinc-based alloys, intermediate range of aluminum concentration led to better elongation. The elongation property of the alloys was affected by temperature in different manners. In a few cases, the elongation initially increased followed by a reduction beyond a specific test temperature, whereas, in other cases, a continuous increase with temperature was noted. The observations made have been discussed in terms of the nature of different microconstituents of the alloys whose effectiveness changes with test conditions. The response of the samples has been further substantiated with their fractographic features and subsurface characteristics.     

Effect of semi-solid forming on the microstructure and mechanical properties of the iron containing Al-Si alloys

Iron is the most common impurity in aluminum casting alloys. The iron-bearing intermetallic compounds have the detrimental effects on the mechanical properties of the alloys. The aim of this research is to study the effects of plastic deformation and semi-solid forming on the morphology and distribution of the iron-bearing intermetallics and the microstructure and mechanical properties of the Al-Si alloys. Different amounts of iron and manganese were introduced into the A380 aluminum casting alloys. The alloys were processed through plastic deformation, recrystallisation and partial melting (RAP), and thixoforming. The microstructure and mechanical properties of the thixoformed alloys were investigated. The results showed that the RAP and thixoforming processes promote the formation of the very fine and well-distributed α-Al₁₅(FeMn)₃Si₂ compounds in the aluminum matrix. The yield and tensile strength as well as elongation of the alloys have been increased considerably by semi-solid forming compared with the as-cast condition.