镁合金的切削加工特性及其应用

论述了镁合金的切削加工性能,并从环保、节能的角度出发探讨了镁合金在汽车工业等方面的应用前景。     

Aluminum Metal-Matrix Composites for Automotive Applications: Tribological Considerations

Aluminum alloys possess a number of mechanical and physical properties that make them attractive for automotive applications, but they exhibit extremely poor resistance to seizure and galling. Reinforcement of aluminum alloys with solid lubricants, hard ceramic particles, short fibers and whiskers results in advanced metal-matrix composites (MMC) with precise balances of mechanical, physical and tribological characteristics. Advanced manufacturing technologies such as squeeze infiltration of molten alloys into fiber performs can be employed to produce near net-shape components. Brake rotors, pistons, connecting rods and integrally cast MMC engine blocks are some of the successful applications of Al MMCs in automotive industry. This paper gives an overview of the tribological behavior of Al MMCs reinforced with hard particles, short fibers, and solid lubricants, and the technologies for producing automotive parts from these novel materials.     

Measurement and optimization of surface roughness and tool wear via grey relational analysis,TOPSIS and RSA techniques

Magnesium alloy (Mg alloy) is one among the lightest materials and which has wide applications in the production of aircraft engines, airframes, helicopter components, light trucks, automotive parts and computers parts for its attractive properties. In this paper, a study to analyze the turning properties of magnesium alloy AZ91D in dry condition with polycrystalline diamond (PCD) cutting inserts is presented. Firstly, to investigate turning of magnesium alloy using grey relational analysis and TOPSIS of optimum cutting parameter values. Secondly, to determine using response surface analysis of mathematical model depending on cutting parameters of surface roughness and tool flank wear in turning. The adequacy of the developed mathematical model is proved by ANOVA. The findings from the investigation showed that feed rate and cutting speed are the dominant factors for surface roughness and tool flank wear respectively.     

Microstructure and mechanical properties of AM50 alloy according to thickness and forming condition of the products by a high pressure die-casting process

In recent years, Magnesium (Mg) and its alloys have become a center of special interest in the automotive industry. Due to their high specific mechanical properties, they offer a significant weight saving potential in modern vehicle constructions. Most Mg alloys show very good machinability and processability, and even the most complicated die casting parts can be easily produced. The die casting process is a fast production method capable of a high degree of automation for which certain Mg alloys are ideally suited. Although Mg alloys are fulfilling the demands for low specific weight materials with excellent machining and casting abilities, they are still not used in die casting process to the same extent as the competing material aluminum. One of the reasons is that effects of various forming variables for die casting process is not closely examined from the viewpoint of die design. In this study, step die and flowability tests for AM50 were performed by die casting process according to various combination of casting pressure and plunger velocity. Microstructure, Vickers hardness and tensile tests were examined and performed for each specimen to verify effects of forming conditions.     

镁铝基耐热铸造镁合金的进展

总结了镁合金的蠕变特点和提高镁合金高温蠕变性能的措施,分析了现有Mg-Al基镁合金耐热性差的原因,综述了当前AZ,AS,AE,Mg-Al-Ca系耐热铸造镁合金的研究和应用状况并指出了以后的发展方向。     

Friction behavior of laser cladding magnesium alloy against AISI 52100 steel

The use of magnesium alloys in engineering applications is becoming increasingly important as a relatively low density allows savings in energy consumption and therefore reduction in air pollution. An associated reduction in inertia makes these alloys potential candidates for friction components, but they suffer from poor wear resistance. Laser surface alloying with appropriate powder mixture is an innovative technique to improve surface properties of metallic alloys. In this study, the effect of laser surface alloying using Al12%Si powder on wear resistance of a magnesium alloy ZE41 is investigated. Hardness and wear resistance of the alloy are significantly enhanced after treatment.     

AZ91D和AM60B镁合金微动图的研究

镁合金在汽车工业中得到了日益广泛的应用 ,在使用中会遇到大量的微动损伤问题。通过大量微动试验 ,建立了AZ91D和AM60B镁合金的微动图 ,通过分析对比了两种镁合金微动区域特性的差异 ,并对镁合金的微动损伤防护方法进行了探讨     

搅拌摩擦点焊技术在汽车行业的应用

随着汽车行业产品的轻量化发展,镁、铝等轻质合金被大量运用,其焊接技术亦为越来越多的工业制造商所关注,搅拌摩擦点焊技术是在搅拌摩擦焊技术的基础上衍生而来的一种适用于轻金属合金连接的新型的固相点焊技术。可以代替熔焊、激光焊、电阻点焊等多种焊接方法,而成为一种新型的搅拌摩擦焊方法。本文将对搅拌摩擦点焊的产生背景、基本原理以及在汽车行业的应用进行简述。     

A study on heat-flow analysis of friction stir welding on a rotation affected zone

In recent years, as interest in environmental protection and energy conservation rose, technological development for lightweight efficiency of transport equipment, such as aircrafts, railcars, automobiles and vessels, have been briskly proceeding. This has led to an expansion of the application of lightweight alloys such as aluminum and magnesium. For the welding of these lightweight alloys, friction stir welding has been in development by many researchers. Heat-flow analysis of friction stir welding is one such research. The flow and energy equation is solved using the computational fluid dynamic commercial program ‘Fluent’. In this study, a rotation affected zone concept is imposed. The rotation affected zone is a constant volume. In this volume, flow is rotated the same as the tool rotation speed and so plastic dissipation occurs. Through this simulation, the temperature distribution results are calculated and the simulation results are compared with the experimental results.     

非晶态合金(4)

非晶态金属具有高强度、高硬度、耐腐蚀和优异的软磁性能 ,在电力、电子、机械、能源和分析设备等方面具有广泛的用途。但由于制备方法所限 ,制备的非晶态合金主要为薄带、细丝、粉末等。因此 ,制备和生产工业实用化的非晶态金属材料 ,成为材料研究和开发工作者的努力目标。本文主要简单地介绍了非晶态合金的制备方法、一般性能特点、用途、种类和应用场合 ,以及目前该方面研究存在的问题和发展方向。     

镁合金低污染化学镀技术研究

镁及其合金表面综合防护性差,表面强化处理成为镁制品加工业中不可或缺的重要环节,化学镀因其众多技术优势在轻合金的表面改性中具有重要地位,但经典的化学镀工艺存在工序繁杂、毒性大、成本高等诸多弊端,针对镁合金化学镀工艺技术中存在的主要问题,对镁合金化学镀展开以低污染、低成本为主要目标的研究。结果表明,改变现有化学镀的镀前处理方式,同样可以实现化学镀镀层的顺利生长,从而以更加环保的方式,在镁合金表面获得致密、光滑、均匀的合金镀层。     

Optimization of welding current waveform for dissimilar material with DP590 and Al5052 by Delta-spot welding process

The automotive industry has a target goal to improve fuel consumption due to restricted exhaust gas regulation. For this reason, the applicability of lightweight material, Al alloys, Mg alloys is also being expanded. In this concept, high strength steel, DP590 and light alloy, AL5052 are joined in the right place of the car body. However, it is difficult to join to steel and aluminum by conventional fusion welding. Generally, in respect to dissimilar metal joining by fusion welding, intermetallic compound layer is formed at the joint interface, hot cracking is generated. In this study, the effect of the current waveform on the mechanical characteristics and microstructure in Delta spot welding process of dissimilar metal was investigated. As results, Intermetallic compound (IMC) layer was reduced from 2.355 μm to 1.09 μm by using Delta spot welding process; also the welding current range improved by 50% in the delta spot welding, higher than in the inverter resistance welding. To conclude, the delta spot welding process adopting the process tapes contributes to improving the welding quality for dissimilar metals (Al5052 and DP590) due to a decrease in IMC layer.

     

有色轻合金在汽车工业中的应用及前景

论述了铝、镁、钛合金的种类及其在汽车上的应用 ,并简介了我国汽车轻合金的应用现状和发展前景     

专用汽车轻量化设计的研究

为了更好地符合环境的发展要求,达到汽车节能减排的作用,汽车的轻量化设计主要依靠铝合金、镁合金塑料以及高强度钢等新材料用量的使用与增加,才能真正意义上地实现环境的保护与资源的节约.汽车轻量化设计成为汽车设计的重要组成部分,也是增强汽车竞争力的有效措施.     

塑料与镁合金移动电话外壳材料的生命周期评价

镁合金资源丰富,是轻质高强的材料且易于回收,具有良好的电磁屏蔽和散热性能,在移动电话外壳材料的应用中得到迅速发展。概述了移动电话的发展及环境污染,应用简式LCA矩阵对塑料和镁合金手机外壳材料进行了初步评价和比较,结果表明虽然镁合金能源消耗较高,但在材料的性能、资源消耗、环境负荷及材料的再生回收性等方面都明显优于塑料。     

一种新的造型材料──镁合金

阐述了镁合金及镁的特性、镁合金的成型技术,并介绍了目前国内外镁合金的应用情况及存在的 问题,为国内产品造型新材料的开发提供了依据。     

Cutting forces and their modelling in plunge milling of magnesium-rare earth alloys

Plunge milling is a machining process already recognised as able to afford significant gains in productivity during the roughing phases, especially in the case of deep workpieces. It is generally used for machining hard materials but more rarely for light alloys, especially for magnesium alloys. This paper deals with the study and the modeling of cutting forces in plunge milling of magnesium-rare earth alloys. In this study, the authors consider the case of a dry plunge milling process applied to two wrought Mg-Zr-Zn-RE alloys and one cast Mg-Zr-Zn-RE alloy, that are representative of magnesium-rare earth alloys in aerospace industry. This paper investigates the influence of cutting parameters and the influence of edge radius on cutting forces. An analytical model is set up so as to satisfactorily predict the cutting forces for these three representative magnesium alloys studied using just three instrumented tests. An experimental validation through different plunge milling tests shows good agreement between the model and the measured values in a wide range of cutting conditions.     

Fatigue crack initiation of magnesium alloys under elastic stress amplitudes: A review

Frontiers of Mechanical Engineering - The most advantageous property of magnesium (Mg) alloys is their density, which is lower compared with traditional metallic materials. Mg alloys, considered...     

Storage location assignment and order picking optimization in the automotive industry

The objective of this study is to design storage assignment and order picking system using a developed mathematical model and stochastic evolutionary optimization approach in the automotive industry. It is performed in two stages. At the first stage, storage location assignment problem is solved with a class-based storage policy with the aim of minimizing warehouse transmissions by using integer programming. At the second stage, batching and routing problems are considered together to minimize travel cost in warehouse operations. A warehouse in the automotive industry is analyzed, and an optimum solution is obtained from an integer programming model. Due to the computational time required for solving the integer programming problem, a faster genetic algorithm is also developed to form optimal batches and optimal routes for the order picker. The main advantage of the algorithm is the quick response to production orders in real-time applications. The solutions showed that the proposed approach based on genetic algorithms can be applied and integrated to any kind of warehouse layout in automotive industry.     

镍铝青铜焊丝进行镁/镀锌钢板点焊的焊接性分析*

以镍铝青铜焊丝为填充材料,对AZ31B镁合金/镀锌钢板进行冷金属过渡点塞焊试验研究,分析镁板上孔直径对镁钢点塞焊接头力学性能的影响.并通过分析焊接接头微观组织及其元素分布状况来研究其连接机理。研究结果表明：使用镍铝青铜焊丝能够得到焊缝美观的镁/镀锌钢异种金属的连接接头。镁/钢板焊接接头的焊缝主要由α-Cu和CuAl₂组成,熔合区由镁的固溶体α-Mg以及Al₂Cu₃Mg₂和Mg₂Cu混合的金属间化合物组成。镁板上孔的直径对镁钢接头性能有很大的影响。随着镁板孔径的增大,镁钢点塞焊接头的最大抗拉载荷先增大后减小,且当镁板孔径为5 mm时接头的最大抗拉载荷达到最大为3.4 kN。焊缝金属和镁母材的连接处即熔合区存在大量脆性金属间化合物,使得镁/钢接头整体力学性能较差。