镁合金消失模铸造的研究现状及发展

针对镁合金消失模铸造的特点综述了镁合金消失模铸造用泡沫材料、消失模制备方法、消失模铸造镁合金充型特性、消失模铸造镁合金铸件的热处理及抗腐蚀性能等研究概况，分析了镁合金消失模铸造有待于进一步解决的问题，提出消失模铸造下一步的研究方向。     

镁合金消失模铸造的研究现状及发展

针对镁合金消失模铸造的特点综述了镁合金消失模铸造用泡沫材料、消失模制备方法、消失模铸造镁合金充型特性、消失模铸造镁合金铸件的热处理及抗腐蚀性能等研究概况,分析了镁合金消失模铸造有待于进一步解决的问题,提出消失模铸造下一步的研究方向。     

镁合金低压铸造机

讨论了用低压铸造生产镁合金铸件的适用性以及镁合金铸造对低压铸造机的技术要求.分析了镁合金低压铸造机的设计方案并对这种新型镁合金低压铸造机进行了阶段性的试验.     

镁合金铸造成型最新研究进展

近年来镁合金在汽车轻量化方面发挥了积极的作用。为了适应镁合金快速发展的需求,镁合金的铸造技术,尤其是压铸技术得到了长足的发展。在传统铸造工艺的基础上介绍了几种镁合金铸造工艺的新进展,主要包括镁合金真空低压消失模铸造新技术、镁合金液态压铸锻造双控成型技术、充氧压铸技术、真空压铸技术、半固态压铸技术、镁合金双辊连续铸轧技术及镁合金电磁连续铸造技术。     

高性能变形镁合金连续铸造技术研究进展

近年来变形镁合金得到了广泛的研究和应用,连续铸造技术为新型变形镁合金提供合格的铸坯.在传统的连续铸造的基础上介绍了镁合金连续铸造的最新研究进展,包括镁合金电磁连续铸造、镁合金双辊连续铸轧、连铸设备自动化远程控制以及连铸坯存在的缺陷等.指出了连续铸造工艺存在的问题和挑战,以及镁合金连续铸造技术的未来发展方向,提出了解决办法.     

镁合金消失模铸造涂料的研究进展

分析了镁合金消失模铸造涂料与铸铁、铸钢、铝合金消失模铸造涂料的不同之处，论述了镁合金消失模铸造涂料的研究进展，指出了镁合金消失模铸造涂料研究的方向。     

挤压铸造Mg-Nd-Gd-Zn-Zr稀土镁合金的显微组织和力学性能

采用砂型铸造和挤压铸造法制备了低稀土含量(低于4％)Mg-Nd-Gd-Zn-Zr镁合金,并对铸态、T6处理态镁合金的显微组织和力学性能进行研究.结果表明:砂型铸造镁合金晶粒粗大,力学性能较低;挤压铸造镁合金的晶粒细小、组织致密,并且气孔、疏松等缺陷较少,拉伸强度比砂型铸造镁合金要高12.9％;经T6处理后,挤压铸造镁合金的拉伸强度提高了27.5％.     

高性能镁合金铸造技术的研究现状

近年来,关于高性能镁合金铸造技术的探索日益加深,在镁合金研究和应用领域取得了很大进展。从国内外高性能镁合金的研究现状入手,介绍了几种高性能镁合金的铸造技术,以及各种铸造工艺和机理,如真空压铸、充氧压铸、连续压铸、半连续铸造等。最后对铸造工艺优缺点进行了的论述,提出了我国高性能镁合金铸造技术发展的措施和前景展望。     

铸造镁合金的发展状况

文章比较详细地介绍了铸造镁合金的发展和现状.重点介绍了镁合金合金化现状、稀土镁合金和阻燃镁合金的研究;同时,对其中所涉及的合金元素及其对铸造镁合金性能的影响进行了概述.以期为致力于铸造镁合金研究的工作者提供参考和借鉴.     

铸造镁合金疲劳研究现状

归纳了典型铸造镁合金的疲劳强度和疲劳寿命研究现状,介绍了铸造镁合金疲劳裂纹的萌生及扩展机制,以及基体组织、晶粒尺寸、第二相、铸造缺陷和工作环境等多种因素对镁合金疲劳性能的影响规律,总结了提高镁合金疲劳性能的方法,最后对铸造镁合金疲劳方面的研究进行了展望。     

稀土Y和Nd对ZM5合金组织和性能的影响

以ZM5镁合金为基体材料，应用铸造方法制备了4种不同稀土含量和比例的稀土镁合金。考察分析了稀土Y和Nd对ZM5合金组织结构、力学性能和腐蚀性能的影响。结果表明，铸态合金中出现了新相Ti2Mg3Al3，它对于减少晶界处第二相的析出有积极作用。ZM5合金的组织结构、力学性能和腐蚀性能随稀土Y和Nd的比例不同而有比较大的差异，在所有考察的ZM5合金中，添加2％Y和1％Nd稀土的合金综合效果最好。     

压铸镁合金高温蠕变研究现状及进展

综述了压铸镁合金高温蠕变的失效形式及机理 ,结合汽车用镁合金部件的实际制备 ,分析和讨论了提高压铸镁合金抗高温蠕变性能的方法 ,提出了在开发耐高温蠕变镁合金时应注意的问题。     

镁合金在3C产品中应用现状及前景展望

镁合金所具有的独特性质使其成为3C产品致力开发的商机.现阶段镁合金用于3C产品的主要为铸造镁合金,成形方法有压铸、触变注射成形和冲锻复合成形等几种,随着现有技术的不断完善和新的成形方法的出现,镁合金将在3C产业中得到越来越广泛的应用.     

Warm deep drawing of wrought magnesium alloy sheets produced by semi-solid roll strip-casting process

This paper is concerned with the development of a continuous strip-casting technology to facilitate the manufacture of magnesium sheet alloys economically whilst maintaining high quality. Established in the paper is warm formability of cast magnesium alloy sheets after being hot rolled by semi-solid roll strip-casting process. It has been found that magnesium sheet with 2.0–4.0 mm thickness could be produced at a speed of 25 m/min. Hot rolling and annealing temperatures during hot rolling were also changed to examine which condition would be appropriate for producing wrought magnesium alloys with good formability. Microstructures of the crystals of the manufactured wrought magnesium alloys were observed. It has been found that a limiting drawing ratio of 2.7 was possible in a warm deep-drawing test of the cast magnesium alloy sheets after being hot rolled.     

Characterization and Modeling Study on Interfacial Heat Transfer Behavior and Solidified Microstructure of Die Cast Magnesium AlloysEI北大核心CSCD

Magnesium alloys are widely used in various fields because of their outstanding properties. High-pressure die casting (HPDC) is one of the primary manufacturing methods of magnesium alloys. During the HPDC process, the solidification manner of casting is highly dependent on the heat transfer behavior at metal-die interface, which directly affects the solidified microstructure evolution, defect distribution and mechanical properties of the cast products. As common solidified microstructures of die cast magnesium alloys, the externally solidified crystals (ESCs), divorced eutectics and primary dendrites have important influences on the final performance of castings. Therefore, investigations on the interfacial heat transfer behavior and the solidified microstructures of magnesium alloys have considerable significance on the optimization of die-casting process and the prediction of casting quality. In this paper, recent research progress on theoretical simulation and experimental characterization of the heat transfer behaviors and the solidified microstructures of die cast magnesium alloys was systematically presented. The contents include: (1) A boundary-condition model developed based on the interfacial heat transfer coefficients (IHTCs), which could precisely simulate the boundary condition at the metal-die interface during solidification process. Accordingly, the IHTCs can be divided into four stages, namely the initial increasing stage, the high value maintaining stage, the fast decreasing stage and the low value maintaining stage. (2) A numerical model developed to simulate and predict the flow patterns of the externally solidified crystals (ESCs) in the shot sleeve during mold filling process, together with discussion on the influence of the ESCs distribution on the defect bands of die cast magnesium alloys. (3) Nucleation and growth models of the primary alpha-Mg phases developed by considering the ESCs in the shot sleeve. (4) Nucleation and growth models of the divorced eutectic phase, which can be used to simulate the microstructure evolution of die cast magnesium alloys. (5) The 3D morphology and orientation selection of magnesium alloy dendrite. It was found that magnesium alloy dendrite exhibits an eighteen-primary branch pattern in 3D, with six growing along < 11(2)over bar0 > in the basal plane and the other twelve along < 11(2)over bar3 > in non-basal planes. Accordingly, an anisotropy growth function was developed and coupled into the phase field model to achieve the 3D simulation of magnesium alloy dendrite.     

REVIEW ON RESEARCH AND DEVELOPMENT OF MAGNESIUM ALLOYS

The current research and development of magnesium alloys is summarized. Several aspects of magnesium alloys are described： cast Mg alloy, wrought Mg alloy, and novel processing. The subjects are discussed individually and recommendations for further study are listed in the final section.     

压铸稀土镁合金高周疲劳试验研究

采用升降法对AZ91D、AZ91D 1?和AZ91D 2?压铸镁合金室温高周疲劳行为进行了试验研究。结果表明:适量稀土Ce的添加能够使压铸镁合金AZ91D的室温拉伸性能和疲劳强度得到提高;利用升降法计算出3种成分合金在应力比R=0.1、循环基数为107下的条件疲劳极限分别为96.7 MPa1、16.3 MPa和105.5 MPa,相当于其抗拉强度的46%左右;合金的疲劳断口呈现出准解理与韧窝断裂的混合特征。     

Microstructure and Mechanical Properties of Mg–RE–TM Cast Alloys Containing Long Period Stacking Ordered Phases: A Review

Casting magnesium alloys hold the greatest share of magnesium application products due to their short processing period, low cost and near net shape forming. Compared with conventional commercial magnesium alloys or other Mg–RE-based alloys, the novel Mg–RE–TM cast alloys with long period stacking ordered(LPSO) phases usually possess a higher strength and are promising candidates for aluminum alloy applications. Up to now, two ways: alloying design and casting process control(including subsequent heat treatments), have been predominantly employed to further improve the mechanical properties of these alloys. Alloying with other elements or ceramic particles could alter the solidifi cation pattern of alloys, change the morphology of LPSO phases and refi ne the microstructures. Diff erent casting techniques(conventional casting, rapidly solidifi cation, directional solidifi cation, etc.) introduce various microstructure characteristics, such as dendritic structure, nanocrystalline, metastable phase, anisotropy. Further heat treatments could activate the transformation of various LPSO structures and precipitation of diverse precipitates. All these evolutions exert great impacts on the mechanical properties of the LPSO-containing alloys. However, the underlying mechanisms still remain a subject of debate. Therefore, this review mainly provides the state of the art of the casting magnesium alloys research and the accompanying challenges and summarizes some topics that merit future investigation for developing high-performance Mg–RE–TM cast alloys.     

镁合金压铸件的生产

叙述了镁合金的特性,并讨论了镁合金贮存、熔炼、精炼以及压铸模具等对生产优质镁压铸件的影响。