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铝合金超塑性分析用试样的一种制备方法 总被引:3,自引:0,他引:3
许晓嫦 《理化检验(物理分册)》1997,33(2):41-41
超塑性的研究现已成为金属材料和压力加工领域的重要学科分支.铝合金由于比强度高,具有良好的耐蚀性等特征,在国民经济和航空工业中得到广泛的应用.许多超塑性研究工作者将它作为重点研究对象.作者在铝合金超塑性性能研究中发现,超塑性变形后分析用样品的制备相当困难.经过试验摸索,发现一种化学抛光腐蚀剂,适于制备铝合金超塑变形后的分析试样,且制备方法简单易行,效果良好.现将此法介绍如下. 相似文献
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针对7B04铝合金开展了变形温度为470~530℃,应变速率为0.0003~0.01s~(-1)的高温超塑性拉伸实验,研究了材料的超塑性变形行为和变形机制。结果表明,7B04铝合金的流动应力随着变形温度的升高和应变速率的降低而逐渐减小,伸长率随之增加;在变形温度为530℃,应变速率为0.0003s~(-1)时,7B04铝合金的伸长率达到最大1105%,超塑性能最佳;应变速率敏感性指数m值均大于0.3,且随变形温度的升高而增加;在500~530℃的变形温度范围内,m值大于0.5,表明7B04铝合金超塑性变形以晶界滑动为主要变形机制;变形激活能Q为190kJ/mol,表明7B04铝合金的超塑性变形主要受晶内扩散控制;7B04铝合金超塑性变形中在晶界附近有液相产生,且适量的液相有利于提高材料的超塑性能。 相似文献
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用超声气体雾化法制备了两种合金化程度较高的新型铝合金,在超声雾化的快速凝固过程中合金得到了很细的显微组织,因而在一定的温度和应变速率下合金具有超塑性。一种 A1-6.7Mg-1.6Li 铝合金在325℃,开始应变速率10~(-2)/秒下显示的最大延伸率为184%,而另一种×7091合金在400℃,开始应变速率9×10~(-3)/秒时呈现218%的延伸率。和常规铸造加锻造的铝合金不同,快速凝固的粉末铝合金在比较高的应变速率下(10~(-2)/秒)即可出现超塑性。 相似文献
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本文对Zn-22%Al材料超塑性状态与非超塑状态进行了挤压及镦粗变形对比,实测了硬度分布及网格变化,对变形区组织也进行了分析。结果表明,由于超塑性状态的应变速率强化敏感及边界粘性摩擦的影响使其变形的特点与非超塑性状态有着明显的区别。对于超塑性状态的正挤压与反挤压变形可观察到其变形区较深,网格畸变剧烈,但是显微组织在各部位变化不大。由于超塑性细晶粒弥散强化的影响,无论是挤压变形还是镦粗变形,超塑性状态的硬度比非超塑性状态的略高。对于镦粗变形,超塑性状态的鼓形肚曲率半径较非超塑性的大。 相似文献
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Superplasticity of fine-grained magnesium alloys for biomedical applications: A comprehensive review
《Current Opinion in Solid State & Materials Science》2023,27(2):101058
The superplastic behavior of medical magnesium alloys is reviewed in this overview article. Firstly, the basics of superplasticity and superplastic forming via grain boundary sliding (GBS) as the main deformation mechanism are discussed. Subsequently, the biomedical Mg alloys and their properties are tabulated. Afterwards, the superplasticity of biocompatible Mg-Al, Mg-Zn, Mg-Li, and Mg-RE (rare earth) alloys is critically discussed, where the influence of grain size, hot deformation temperature, and strain rate on the tensile ductility (elongation to failure) is assessed. Moreover, the thermomechanical processing routes (e.g. by dynamic recrystallization (DRX)) and severe plastic deformation (SPD) methods for grain refinement and superplasticity in each alloying system are introduced. The importance of thermal stability (thermostability) of the microstructure against the grain coarsening (grain growth) is emphasized, where the addition of alloying elements for the formation of thermally stable pinning particles and segregation of solutes at grain boundaries are found to be major controlling factors. It is revealed that superplasticity at very high temperatures can be achieved in the presence of stable rare-earth intermetallics. On the other hand, the high-strain-rate superplasticity and low-temperature superplasticity in Mg alloys with great potential for industrial applications are summarized. In this regard, it is shown that the ultrafine-grained (UFG) duplex Mg-Li alloys might show remarkable superplasticity at low temperatures. Finally, the future prospects and distinct research suggestions are summarized. Accordingly, this paper presents the opportunities that superplastic Mg alloys can offer for the biomedical industries. 相似文献
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Ya. I. Rudaev 《Strength of Materials》1990,22(10):1445-1451
Existing ideas about reasons for the occurrence and phenomenology of development of the superplasticity effect are analyzed. It is shown that within the scope of the thermodynamic approach superplasticity depends on a diffuse phase transition accomplished with heating and deformation. Traditional evaluation of super-plasticity from the value of the rate sensitivity factor is considered. Conditions are determined which should be fulfilled with transfer of material into a super-plastic condition, in particular for wrought aluminum alloys without a previously prepared structure.Translated from Problemy Prochnosti, No. 10, pp. 50–54, October, 1990. 相似文献
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Processing by severe plastic deformation (SPD) leads to very significant grain refinement in metallic alloys. Furthermore, if these ultrafine grains are reasonably stable at elevated temperatures, there is a potential for achieving high tensile ductilities, and superplastic elongations, in alloys that are generally not superplastic. In addition, the production of ultrafine grains leads to the occurrence of superplastic flow at strain rates that are significantly faster than in conventional alloys so that processing by SPD introduces the possibility of using these alloys for the rapid fabrication of complex parts through superplastic forming operations. This paper examines the development of superplasticity in various aluminum alloys processed by equal‐channel angular pressing (ECAP). 相似文献
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镁合金因其密度小、比性能好、减震性能好、电磁屏蔽性好等优异性能,在航空航天、电子产品、汽车行业等有着良好的应用前景。目前镁合金还没有投入大规模工业化生产,主要原因之一就是镁合金塑性变形能力差,难以成形为复杂形状的部件。超塑性成形为这一问题的解决提供了可能,因此镁合金超塑性的研究受到了广泛重视。综述了近年来国内外Mg-Al系、Mg-Zn系、Mg-Li系和Mg-Gd系镁合金超塑性研究进展,发现不同体系的镁合金经过不同的处理方法,在理想条件下的超塑性伸长率均能达到400%以上,表现出优异的超塑性,最后对今后进一步的发展方向作出了展望。 相似文献
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超塑性是材料在一定温度和应变速率下表现出异常高塑性的能力。Mg-Li合金具有超轻的密度、高比刚度和良好的电磁屏蔽能力,可望在航天、军事、汽车、3C电子等领域获得应用。综述了国内外Mg-Li合金超塑性研究现状,介绍了轧制、挤压、等通道转角挤压、搅拌摩擦加工、差速轧制、高压扭转和多向锻造方法获得的超塑性。指出了Mg-Li合金超塑性存在的问题和今后进一步研究的方向。 相似文献
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V. N. Perevezentsev M. Yu. Shcherban’ M. Yu. Murashkin R. Z. Valiev 《Technical Physics Letters》2007,33(8):648-650
The structure and mechanical properties of nanocrystalline aluminum alloy 1570 obtained by means of severe plastic deformation have been studied. Being tested in a temperature range from 300 to 400°C, the alloy exhibits high-strain-rate superplasticity. At 400°C, the superplasticity is manifested in a very broad range of strain rates, extending from 5 × 10?3 to 1 s?1. 相似文献