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随着镁合金产业的快速发展,如何通过塑性成形方法提高镁合金的耐蚀性成为了重要课题。镁及其合金因具有低密度、高比强度和较好的回收性等优点而受到广泛关注,然而室温变形能力和耐腐蚀性能差等缺点是其广泛应用的瓶颈。在总结镁合金腐蚀特点及面临问题的基础上,综合分析了国内外塑性成形方法对镁合金腐蚀领域的相关研究,综述了不同加工成形方法在提高镁合金耐蚀性应用方面的进展,从腐蚀机理和工艺参数2个方面进行了讨论。介绍了不同塑性成形方法对镁合金耐蚀性的影响机制,其中包括挤压–ECAP、超声滚压处理、等通道转角挤压、热轧处理、触变成形、板材挤压、板材轧制、交叉轧制、异步轧制和异步交叉轧制、压铸、快速凝固、搅拌摩擦焊、增材制造、喷丸等。从成分分布、析出相等微观角度阐述了影响镁合金腐蚀行为的机制,指出了塑性成形方法在提高镁合金耐蚀行为方面存在的问题,为提高镁合金的耐蚀性提出建议。 相似文献
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对ME20M镁合金板料进行了热拉深成形性能实验与数值模拟.研究表明,ME20M镁板热拉深成形极限高度随实验参数的不同而不同,其塑性成形性能随温度的升高明显改善;数值模拟可以很好地预测不同实验参数下镁合金板料热拉深成形极限的高度.对热拉深成形件传力区部位进行金相实验得知,合理控制热拉深实验参数能保证镁合金塑性成形件微观组织,进而保证成形件质量. 相似文献
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综述了镁合金的塑性成形工艺性能、镁合金丝成形工艺方法的研究现状和镁合金丝成形工艺的发展趋势。形变温度、载荷形式和晶粒尺寸对镁合金的塑性变形能力影响很大;通过升高温度和使镁合金处于三向压应力状态可以显著提高镁合金的塑性,因此热挤压是一种可行的镁合金丝塑性成形方法;拉拔成形过程中的应力状态对镁合金的塑性发挥不利,但在镁合金丝拉拔过程中引入电磁场、电脉冲等外场可以使镁合金的温度快速升高、晶粒细化,从而大幅提高镁合金的塑性,外场作用下生产效率极高的拉拔成形新技术是未来镁合金丝成形工艺的研究与发展方向。 相似文献
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镁合金由于具有质量轻、比强度和比刚度高以及良好的铸造性能等特点,在理论研究和实际应用上引起了人们极大的关注。近年来,世界各国纷纷致力于镁合金的研究开发。本文综述了国内外主要的变形镁合金材料的基本特性、力学性能和应用领域,介绍了目前变形镁合金材料的研究现状和进展,以及制备高性能变形镁合金材料的新工艺,探讨了镁合金的合金化原理和主要合金元素在变形镁舍金中的作用。 相似文献
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选区激光熔化成形作为一种新兴的增材制造工艺,可以实现轻质镁合金复杂构件的一体化精密成形。由于镁合金的化学性质活泼,镁合金的选区激光熔化成形相较于其他合金系更具挑战性,沉积构件的强度、塑性、韧性等力学性能指标整体偏低,抗腐蚀性能整体偏差,所以还需进一步提升其综合性能并拓展镁合金的应用领域。综述了近年来国内外关于镁合金选区激光熔化成形方面的研究,为镁合金的精密一体化成形提供相应的理论基础和指导策略。首先阐述了该新兴工艺的原理及特点,基于镁合金熔沸点低、饱和蒸气压高等特点,综合探讨了微裂纹、孔隙和杂质等缺陷的形核原理,提出了相应的缺陷控制策略。对沉积试样的微观组织进行了分析,并与传统工艺进行了比较,并基于此讨论了合金成分微调控和镁基复合材料这 2 种实现成分微调控的主要方案。最后结合热处理、热等静压等后处理方式调控微观组织,并对采用摩擦搅拌、激光冲击强化等强化工艺结合选区激光熔化的复合增材制造工艺在线闭合缺陷、调控微观组织等技术进行展望,希望可以进一步提升镁合金的综合性能,促进镁合金更广泛的工程应用。 相似文献
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近年来,随着能源问题和环境问题的日益严峻,作为轻量化合金代表之一的镁合金得到了人们普遍的关注。特别是低合金化镁合金,因其具有优异的可加工性能、好的耐蚀性、低成本(密度)以及可提高镁合金塑性等优势而引起了国内外学者的广泛关注。然而,低合金含量镁合金获得的绝对强度难以满足实际的工况需求,使其应用面临着严峻的挑战,高强度低合金化镁合金可进一步拓展镁合金的应用范围。综述了近年来高强度低合金化镁合金的研究进展,系统分析了不同体系高强度低合金化镁合金的高强高韧化机理,并展望了未来高性能低合金化镁合金研究的发展方向。 相似文献
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Recent studies indicate that there is a high demand for designing magnesium alloys with adjustable corrosion rates and precipitation ability of bone-like apatite layer on the surface of magnesium alloys in body. An approach to this challenge might be the application of nanocomposites based on magnesium alloys. The aim of this work was fabrication and bio-corrosion evaluation of a nanocomposite that was made of magnesium alloy AZ91 as matrix and fluorapatite (FA) nano particles as reinforcement. Magnesium-fluorapatite nanocomposite (AZ91-20FA) was made via the blending-pressing-sintering method. In vitro corrosion measurements were performed for characterization of initial materials and produced composite. The results showed that the addition of FA nano particles to magnesium alloy as reinforcement can reduce the corrosion rate and accelerate the formation of bone-like apatite layer and in turn provide better protection for matrix alloy. It is suggested that the formation of bone-like apatite layer on the surface of magnesium alloy might contribute to the good osteoconductivity of magnesium alloys. 相似文献
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Erlin Zhang Dongsong Yin Liping Xu Lei Yang Ke Yang 《Materials science & engineering. C, Materials for biological applications》2009,29(3):987-993
Mn and Zn were selected to develop a Mg–Zn–Mn magnesium alloy for biomedical application due to the good biocompatibility of Zn and Mn elements. Microstructure, mechanical properties, corrosion properties and biocompatibility of the Mg–Zn–Mn alloys have been investigated by use of optical microscope, scanning electron microscope, tensile testing, and blood hemolysis and cell toxicity. Microstructure observation has shown that the addition of Zn and the extrusion significantly refined the grain size of both the as-cast and the extruded magnesium alloys, which mainly contributes to the high tensile strength and good elongation. Polarization test has shown Zn could accelerate the formation of a passivation film, which provides good protection to the magnesium alloy against simulate body fluid. Cell culture and hemolysis tests have shown that the magnesium alloy did not have cell toxicity, showing good cytocompatibility, but the alloy caused hemolysis to blood system. It was suggested that surface modification have to be adopted to improve the blood compatibility of the magnesium alloy for the application in blood environment. 相似文献
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Magnesium – future material for automotive industry? Magnesium alloys show a very high potential in automotive applications as constructive metal, whereas the main focus lies on die cast parts. Electronic industry is the major commercial consumer for die castings besides the automobile industry. Room temperature applications like steering wheels and frame components in cars as well as mobile phone‐ or notebook housings are well established. These castings are produced with AZ‐ or AM‐magnesium alloys, which show good room temperature properties and a good castability. The great alloy development challenge in extending the use of magnesium cast alloys are application for higher temperatures. The application in powertrain components is considered to be the benchmark here. Besides alloy development there are also further research activities in development of casting processes. Semi‐solid processes like New‐Rheocasting (NRC), Thoxomolding ? or Thixocasting (TC) are adapted to the requirements of newly developed alloys. Not only cast alloys but also magnesium wrought alloys have moved to the centre of interest in the last decade. Alloy development for improving the formability on the one hand as well as process development in extrusion or rolling has to be done in order to find optimum parameters for deforming magnesium alloys properly. 相似文献