共查询到17条相似文献,搜索用时 93 毫秒
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本文总结了稀土镁合金的研究工作。概要论述了稀土镁合金的发展进程;在稀土元素对镁合金性能影响方面,阐明了稀土元素对镁合金密度、电阻系数和导热系数、热膨胀系数、阻尼容量、晶格常数、弹性模量等物理性能以及对拉伸和蠕变等力学性能的影响。在稀土镁合金微观结构研究方面,总结了稀土相的结构,以及稀土相对合金的强化作用,并提出了我们的一些研究结果。 相似文献
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新型高强Mg-Zn-Zr-RE合金的微观结构 总被引:2,自引:0,他引:2
一、前言 镁合金由于具有低的密度,相对高的比强度和比弹性模量等特点,不仅在航空航天领域,而且在民用产品结构件上,都是具有吸引力的。但由于其强度低,因而影响了应用。多年来,为了改善合金的性能,利用稀土元素在镁合金中的作用,国外已发展了多种系列的稀土镁合金。我国富产稀土资源,发展稀土镁合金具有广阔的前景。在Mg-Zn-Zr系的MB15镁合金基础上,研制了Mg-Zn-Zr-Y合金MB25,以及用富Y混合稀土(MM)代替高品位Y的Mg-Zn-Zr-MM系的MB26,其性能与MB25合金相当。为了进一步利用稀土元素改善合金的性能,研制了低Zn、高RE含量的新型Mg-Zn-Zr-RE系合金,其性能高于MB25和MB26合金。作为研制新型合金的基础,本文通过与MB26合金对比,研究了Mg-Zn-Zr-RE系合金的微观组织与相组成。 二、实验方法 相似文献
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采用扫描电镜(SEM)、X射线衍射(XRD)、能谱分析(EDS)研究添加(La,Ce)混合稀土前后AZ91镁合金在融雪剂溶液中经历干/湿交替循环腐蚀后腐蚀产物的组成和结构。结果表明:未添加(La,Ce)混合稀土的AZ91镁合金的腐蚀产物主要由Mg(OH)_2,MgO,CaCO_3及Mg_6Al_2CO_3(OH)_(16)·4H_2O组成;而添加混合稀土的AZ91镁合金表面生成了(La,Ce)AlO_3等含稀土元素的腐蚀产物,同时腐蚀产物出现致密层。不同周期干/湿交替循环腐蚀的电化学阻抗谱(EIS)测试结果表明,添加(La,Ce)混合稀土的镁合金在相同腐蚀周期的阻抗谱幅值均高于AZ91镁合金的阻抗谱幅值,稀土的添加有助于降低阻抗谱的弥散效应,表明(La,Ce)混合稀土可以提高AZ91镁合金在干/湿交替腐蚀环境中的耐蚀性和腐蚀产物膜的稳定性。 相似文献
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Drahomír Dvorský Jiří Kubásek Ilona Voňavková Dalibor Vojtěch 《Materials Science & Technology》2019,35(5):520-529
Rare earth elements are known to improve both mechanical and corrosion properties. However, it highly depends on the final microstructure conditions of prepared material. During extrusion, intermetallic phases may be redistributed, partially dissolved or on the contrary, precipitated. The knowledge of the impact of extrusion on the individual alloys is therefore essential for their application. In this work, three magnesium alloys (Mg-4Y-3RE, Mg-2Y-1Zn, Mg-3Nd-0.5Zn) were prepared by an extrusion process. Microstructure, mechanical and corrosion properties were compared with extruded pure Mg. The advantages and disadvantages of individual alloys are discussed. Based on the obtained results, the Mg-4Y-3RE alloy seems to exert the best mechanical and corrosion properties. Other materials were characterised with anisotropy of mechanical properties and much higher corrosion rate. 相似文献
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超高强韧镁合金的研发对推广镁合金在高技术领域的应用具有重要意义。镁与稀土均是我国的优势资源,因此在我国发展超高强韧稀土镁合金具有得天独厚的优势,其中Mg-Gd-Y-Zn-Zr系变形镁合金因其接近高强铝合金的超高强度和塑性,近年来受到研究者的广泛关注。综述了超高强韧Mg-Gd-Y-Zn-Zr系变形镁合金的合金成分、常规塑性变形工艺、新型剧烈塑性变形工艺和热处理工艺对该合金显微组织和力学性能的影响规律,以及该超高强韧变形镁合金的显微组织特征和强韧化机理。T5峰时效态超高强韧Mg-8.2Gd-3.8Y-1Zn-0.4Zr(质量分数)挤压合金具有双峰分布的晶粒尺寸“软-硬”复合层片微结构,以及由高密度的基面γ′纳米片状析出相和棱柱面β′纳米析出相形成的近连续网状结构,该挤压合金室温拉伸屈服强度、拉伸强度和断裂延伸率分别为466 MPa、514 MPa和14.5%。介绍了哈尔滨工业大学等单位在超高强韧Mg-Gd-Y-Zn-Zr系变形镁合金的规模化制备和应用方面的研究进展,并展望了Mg-Gd-Y-Zn-Zr系变形镁合金的发展趋势。 相似文献
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D. Griffiths 《Materials Science & Technology》2015,31(1):10-24
Wrought magnesium alloys are rarely used due to their poor formability which is caused by strong textures created during processing. Addition of rare earth (RE) elements including Y, Ce, La, Gd and Nd weakens these strong basal textures and significantly improves formability. Developing a mechanistic understanding of this effect is critical in leading alloy design towards a new class of highly formable magnesium alloys. This fall in texture intensity occurs during recrystallisation and only requires very low solute RE additions, 0·01 at.-% in the magnesium–Ce case. These additions retard dynamic recrystallisation and increase non-basal slip; however, a full understanding of the RE effect has yet to be obtained, with a variety of mechanisms proposed. Recent research in these areas is critically reviewed. 相似文献
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目的 为了使Mg–Zn–Zr合金在热加工过后具有良好的力学性能及变形各向同性,在Mg–2Zn–0.5Zr合金中添加不同含量的稀土元素,研究稀土元素对Mg–2Zn–0.5Zr合金轧制后微观组织和力学性能的影响规律,以解决变形镁合金织构强、变形各向异性强的问题。方法 通过添加不同含量(0.2%和0.8%,质量分数)的混合稀土元素,采用轧制的方法制备镁合金板材。通过SEM(扫描电子显微镜)、EDS(能谱仪)、EBSD(背散射电子衍射)和电子万能试验机等对镁合金板材的成分、微观组织、织构以及拉伸过程中的应力–应变曲线进行分析。结果 混合稀土元素的添加会明显提高Mg–Zn–Zr合金板材的轧制成形性,可以起到细化晶粒、弱化轧制织构的作用,能够提高材料的伸长率并改善力学性能的各向异性。混合稀土元素会与Mg、Zn在晶界处形成第二相,但并不会影响稀土元素的织构弱化效果。与较低稀土元素(质量分数为0.2%)时相比,当混合稀土元素含量较高时(质量分数为0.8%),合金材料的力学性能各向异性更优,这主要是由于添加较多的稀土元素,形成了 织构,使添加较多稀土元素的合金材料的织构强度更强。结论 随着混合稀土元素的添加,Mg–2Zn–0.5Zr合金的织构强度先降低后升高,并且随着材料织构弱化,材料力学性能的各向异性减弱。 相似文献
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Effect of dynamic strain aging on the appearance of the rare earth texture component in magnesium alloys 总被引:1,自引:0,他引:1
Binary Mg alloys were prepared containing Zn, Ce and Gd. These were extruded and the resulting mechanical properties were determined. The intensities of the rare earth (RE) texture components were measured and linked to the extrusion conditions. Tension and compression testing was carried out on samples taken from extruded bars and a Mg-0.5Ce cast alloy. Over particular temperature and strain rate ranges, dynamic strain aging (DSA) was observed. The ranges over which DSA occurred during testing are compared with the conditions under which the RE texture components were produced during extrusion. It is concluded that formation of the RE texture components can be enhanced by extruding when the rate sensitivity is negative, i.e. under conditions where DSA is taking place. 相似文献