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机械毕业设计英文翻译

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英文翻译外文文献翻译477镁薄板合金成形的可锻性和可成形性的加工技术,机械毕业设计英文翻译

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1 镁薄板 合金 成形的 可锻 性和可成形性的 加工技术 摘要 金属成型和金属成形机床的新发展 ， 显示 了 镁 薄 片 具 有优秀的模铸性能 ，如果 工艺是 在高温 下 传导 。对镁薄片成型的相应的机械性能的估价， 已经在各种各样的温度和应变率 的条件下 进行 的单轴向 拉力的测试 。镁合金 az31b、 az61b的拉深测试和 m1在 200-250温度范围之间都有 很好可成形性 ，除温度之外， 已经研究 出 的极限拉延比 也影响模铸的 速度 。 产生 的 结果得出有可能由 镁 薄片 合金混合物 代替 传统的铝和钢薄片的结论。 引言 为了减少燃料消耗、一般 已经有的 成就 是减少汽车构造 的重量的，增加 重量轻的物资 的使用，在这个条件下、镁合金具有对 工商企业集团 有特殊的使用价值， 因为他们的密度低 ，只有 1.74 g cm3。 不久的将来 镁合金 将成为汽车零件 模铸 的主要地材料 。 模具铸件技术允许放弃 制造 过程中 复杂的几何结构。 然而， 这个部分 的机械性能 经常不能满足 机械性能 的必要条件， （例如耐久强度和延性）。一种有希望 能 替换 的材料， 毫无疑问是 将 模铸 工艺 带进简便化， 那部分 对 机械性能和细粒的微观结构 有利的 没有气孔 的制造技术。然而、一种广泛被应用的模铸技术在 镁合金 的成型的工艺中受到了 限制 ， 模铸技术和适当的工艺参数 的不完善而不得不应用（ 2,3） 。 镁薄 板金属部件 的应用对汽车 车身 的 构造提供一个 很 大的潜力 。通常、 汽车的 车身完全 由 板料冲压和表现 大约 25%飞行器质量nts 2 组成。所以， 镁 薄 片 替代传统的材料 应用 ，将导致 重量 减轻的实质 。 镁薄片的塑料性质 镁合金在室温下显示 出 可成形性 的 极限 ，这个六方晶体和孪晶 体的 倾向是唯一的允许有限 的 形变。 那不同地定向微晶 在独立基础滑动平 面 显示 出 畸形 ， 导致一个相互的滑动障碍 （ 、 ） 。通过 应用的温度 完善可以对 模铸品质 进行可观的改善！ 在 200 -225温度范围里的可成型性的提高具有很好的可观性 （依靠合 金成分） 见文献的研究 。在棱形滑动面 的 六方 形 结构 的热活化性中发现了这个效果，见文献 。 2.1成型温度 对 流动应力的影响 一种 对 镁 薄 片畸形性质要求 的 测定 的 详细研究 的金属的特征值同样各 向异性或流动曲线 见 、 。因为在这个领域里 的 系统研究 表明对 各种各样的镁合金的温度和应变率的可塑性的大量的调查涉及金属成型和金属成形机床的原理 的影响 不是可利用的 （ ifum）。图 1； 显示 镁 金属 az31b在不同温度的流动曲线 、 显然那应力和可能的拉紧力 ， 大量地依靠 在 那成型温度nts 3 上。在 2008c以上温度范围 内流动应力的减少随温度的 变 化而的变化 。 3 镁 合金的拉深 为了要 研究 镁薄片 在不同的成型温度 的可模锻性，在 IFUM与圆筒形工具系统 中进行 拉深测试 ，图 3显示在 50c的温度的拉深测试的结果。然而那 az31b在低点 b01： 45可能的拉深比率（拉深： 30mm）合金az61b和 m1显示早的破裂，使用 b01： 6的拉深比率 ， AZ31 B 显示与 AZ61 B 和 M 1 类似的 破裂，这些测试 确定 镁合金的可模锻的低点温度 。 然而 ， 调查结果显示镁合金在高温的情况下有非常好的模锻性 。发现 在 2008c温度下 az31b的成型温度 具有 最大 bo的拉深比率 ， az61b和 m1显示 铝合金 b0的最大价值提高到 2： 20： 2.25.， AlMg4.5 Mn0.4 的nts 4 比较显示铝合金在室温下非常容易模锻 ,镁合金 的 增加的拉深 比率 在低点温度与提高温度的比较，结果表明 从可拉 长的测试显示那应力比率在镁合金的机械道具的重要的影响力 。 参考文献。 1 H. Kehler et al., Partikelverstarkte Leichtmetalle, Metall Band, 49,Heft 3, 1995. 2 E. Doege, K. Droder, St. Janssen, Leichtbau mit Magnesiumknetlegierungen Blechumformung und Prazisionsschmieden TechnischerMg-Legierungen, Werkstattstechnik, Band 88, Heft 11/12,1998. 3 E. Doege, K. Droder, F.P. Hamm, Sheet Metal Forming ofMagnesium Alloys, Proceedings of the IMA-Conference on MagnesiumMetallurgy, Clermont-Ferrand, France, October 1996. 4 H.J. Bargel, G. Schulze, Werkstoffkunde, VDI-Verlag GmbH,Dusseldorf, 1988. 5 C.S. Roberts, Magnesium and Its Alloys, Wiley, New York, 1960. 6 G. Siebel, in: Beck (Ed.), Technology of Magnesium and Its Alloys,Hughes, London, 1940. 7 N.N.: Magnesium and Magnesium Alloys, Ullmanns Encyclopediaof Industrial Chemistry, Reprint of Articles from 5th Edition, VCH,Weinheim, 1990. 8 E. Doege, K. Droder, Processing of magnesium sheet metals by deepdrawing and stretch forming, Mat. Tech. 78 (1997) 1923. 9 E. Doege, K. Droder, St. Janssen, Umformen von Magnesiumwerkstoffen,DGM-Fortbildungsseminar, Clausthal-Zellerfeld, Oktober1998, pp. 2830. 10 L. Taylor, H.E. Boyer, in: E.A. Durand, et al. (Eds.), MetalsHandbook, 8th Edition, Vol. 4, American Society of Metals, Cleveland, OH, 1969. nts 1 Sheet metal forming of magnesium wrought magnesium wrought alloys formabilityand process technology Abstract New developments at the for Metal Forming and Metal Forming Machine Tools show that magnesium sheets possess excellent forming behavior, if the process is conducted at elevated temperatures. For the evaluation of mechanical properties relevant for forming of magnesium sheets, uni axial tensile tests have been carried out at various temperatures and strain rates. Deep drawing tests with magnesium alloys AZ31B, AZ61B, and M1 show very good formability in a temperature range between 200 and 2508C. Besides temperature, the influence of forming speed on limit drawing ratio has been investigated. The obtained results lead to the conclusion that it is possible to substitute conventional aluminum and steel sheets by using magnesium sheet metal wrought alloys. 1. Introduction In order to reduce fuel consumption, general efforts have been made to decrease the weight of automobile constructions by an increased use of lightweight materials. In this framework, magnesium alloys are of special interest because of their low density of 1.74 g/cm3. Presently, magnesium alloys for the use as automobile parts are mainly processed by die casting. The die casting technology allows the manufacturing of parts with complex geometry. However, the mechanical properties of these parts often do not meet the requirements concerning the mechanical properties (e.g. endurance strength and ductility). A promising alternative has to be seen in components that are manufactured by forming processes. The parts manufactured by this technology are characterized by advantageous mechanical properties and fine-grained microstructure without pores 1. However, a widespread use of forming technologies for the processing of magnesium alloys is restricted because of insufficient knowledge about the forming technologies and suitable process parameters that have to be applied 2,3. Automotive body constructions offer a great potential for the application of magnesium sheet metal components. In general, the automotive body completely consists of sheet metal parts and represents a share of about 25% of the entire vehicle mass. Therefore, the substitution of conventional sheet materials by magnesium sheets would lead to essential weight savings in this application. nts 2 2. Plastic material properties of magnesium sheets Magnesium alloys show a limited formability at room temperature. This results from the fact that the hexagonal crystal structure and the low tendency to twinning only allow limited deformations. The differently orientated crystallites only show a deformation on the individual base slip plane, which leads to a mutual slip hindrance 4, 5. A considerable improvement of the forming qualities can be achieved by applying temperature. The considerable increase in formability that occurs in the temperature range from 200 to2258C (depending on alloying composition) was investigated by Siebel 6. The reason for this effect was found in the thermal activation of pyramid sliding planes in the hexagonal structure 7. 2.1. Influence of forming temperature on flow stress A detailed evaluation of the deformation properties of magnesium sheets requires the determination of the materials characteristic values like anisotropy or flow curves 8, 9. Because systematic investigations in this area are not available, extensive investigations concerning the influence of temperature and strain rate on plastic properties of various magnesium alloys were performed at Institute for Metal Forming and Metal Forming Machine Tools (IFUM). Fig. 1 displays flow curves of magnesium sheet material AZ31B at different temperatures, determined in the uniaxial tensile test according to EN 10002, part 5. It is obvious that the stresses and possible strains largely depend on the forming temperature. The decrease of flow stresses in the temperature range above 2008C attributes to temperature-dependent relaxation. nts 3 3. Deep drawing of magnesium alloys In order to investigate the formability of magnesium sheets, deep drawing tests at different forming temperatures were carried out at IFUM with a cylindrical tool system.Fig. 3 shows the results of deep drawing tests at a temperature of 50C. Whereas the deep drawing of the alloy AZ31B using a low drawing ratio of b0 1:45 was possible (drawing depth: 30 mm), the alloys AZ61B and M1 showed early fracture. Using drawing ratio of b0 1:6, AZ31B showed fracture similar to AZ61B and M1. These tests confirm the low formability of magnesium alloys at low temperature. However, the investigated magnesium alloys show very good formability at higher temperature ， The maximum limit drawing ratio of b0 ; max 2:52 was detected for AZ31B at a forming temperature of 2008C. AZ61B and M1 show maximum values of approximately b0 ; max 2:20 up to 2.25. The values of the aluminum alloy AlMg4.5Mn0.4 are displayed for comparison. Due to the good formability of the aluminum alloy at room nts 4 temperature, the increase in limit drawing ratio with rising temperature is low compared to the magnesium alloys.The results gained from the tensile tests showed the significant influence of strain rate on the mechanical properties of magnesium alloys. 1 H. Kehler et al., Partikelverstarkte Leichtmetalle, Metall Band, 49, Heft 3, 1995. 2 E. Doege, K. Droder, St. Janssen, Leichtbau mit Magnesiumknetlegierungen Blechumformung und Prazisionsschmieden Technischer Mg-Legierungen, Werkstattstechnik, Band 88, Heft 11/12, 1998. 3 E. Doege, K. Droder, F.P. Hamm, Sheet Metal Forming of Magnesium Alloys, Proceedings of the IMA-Conference on Magnesium Metallurgy, Clermont-Ferrand, France, October 1996. 4 H.J. Bargel, G. Schulze, Werkstoffkunde, VDI-Verlag GmbH, Dusseldorf, 1988. 5 C.S. Roberts, Magnesium and Its Alloys, Wiley, New York, 1960. 6 G. Siebel, in: Beck (Ed.), Technology of Magnesium and Its Alloys, Hughes, London, 1940. 7 N.N.: Magnesium and Magnesium Alloys, Ullmanns Encyclopedia of Industrial Chemistry, Reprint of Articles from 5th Edition, VCH, Weinheim, 1990. 8 E. Doege, K. Droder, Processing of magnesium sheet metals by deep drawing and stretch forming, Mat. Tech. 78 (1997) 1923. 9 E. Doege, K. Droder, St. Janssen, Umformen von Magnesiumwerksto