共查询到19条相似文献,搜索用时 109 毫秒
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Al和Ca对变形镁合金性能的影响 总被引:7,自引:1,他引:6
采用环境扫描电镜(ESEM)和能谱分析研究了添加元素Al和Ca对变形镁合金结构和性能的影响.结果表明,Al是镁合金中强化相β相的组成元素,β相呈片层状,片层与镁基体α相的基面平行或垂直.Al含量的增加使镁合金中β相也增加,提高了镁合金的强度但降低了其塑性;Ca主要分布于β相中,与Mg结合生成Mg2Ca相,提高了β相的高温稳定性,改变了挤压后β相的形貌和分布,减少了再结晶过程中晶界β相的析出量,有效地提高了镁合金的塑性,但是使强度稍有降低. 相似文献
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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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Creep resistant magnesium alloys are candidate materials for automotive powertrain applications. Since the 90's, a number of new creep‐resistant magnesium alloy systems have been investigated and developed. These are for the most part based on rare‐earth, alkaline earth, and silicon additions. This paper gives an overview of creep resistance in magnesium and a review of creep resistant magnesium alloys for power‐train applications. 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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采用真空座滴法和熔铸法研究了在Al-Zn-Mg-Cu 合金中加入稀土(Ce、Y) 对Al2Zn2M g2Cu/Al2O3陶瓷界面润湿性的影响。结果表明,Al-Zn-Mg-Cu 合金中加入稀土可有效降低铝合金/Al2O3界面的接触角, 改善界面结合状态; 稀土改善界面润湿性存在一最佳含量范围, 添加Ce 的最佳含量约为0. 5w t% , Y 约为0. 7w t%。稀土改善润湿性的作用主要是稀土与Al2O3膜、Al2O3陶瓷发生反应。Mg、Zn、Cu 等合金元素在界面富集并参与界面反应对润湿性有利; 稀土与Mg、Zn、Cu 等合金元素适当组合改善润湿性的效果比单一稀土明显。 相似文献
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J. D. Robson 《Materials Science & Technology》2015,31(3):257-264
This assessment is focussed on wrought magnesium alloys for lightweight applications, particularly in the transport sector. The challenges to their wider use are summarised, including poor low temperature formability, corrosion issues, dissimilar metal joining, and limited precipitation strengthening. The fundamental origins of these challenges, and current research to address them, are highlighted. Key developments such as the use of dilute rare earth additions to manipulate texture for improved formability are discussed. Opportunities to exploit the unique properties of wrought magnesium alloys where further research is required are identified. 相似文献
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Jingli Yan Yangshan Sun Feng Xue Jing Bai Shan Xue Weijian Tao 《Journal of Materials Science》2008,43(21):6952-6959
Two heat-resistant magnesium alloys AJC421 and Mg-2Nd were prepared. Both as-cast Mg-2Nd and AJC421 alloys exhibited good
creep resistance in comparison with commonly used magnesium alloys. The improvement in creep properties through Nd addition
to pure magnesium is attributed to both solid solution and precipitation hardening. The stress exponents of 4.5–5.5 and activation
energies of 70.0–96.0 kJ/mol obtained from the as-cast Mg-2Nd alloy at low temperatures and low stresses indicate the five
power law can be used for predicting the creep mechanism. The additions of alkaline earth elements Sr and Ca into Mg–Al alloys
suppress the discontinuous precipitation of Mg17Al12 and form thermal-stable intermediate phases at grain boundaries, leading to effective restriction to grain boundary sliding
and migration. However, the mechanism responsible for creep deformation of Mg–Al based alloys with Ca and Sr additions is
not consistent with the results of microstructure observations performed on the alloys before and after creep tests. 相似文献
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A. Ditze K. Schwerdtfeger C. Scharf C.‐T. Mutale 《Materialwissenschaft und Werkstofftechnik》2001,32(1):31-35
Utilization of magnesium scrap At present the applications of magnesium alloys grow rapidly. Therefore the recycling of magnesium gets new importance. Starting from the demand of magnesium alloys the material cycle of magnesium including the primary production, the consumption and the recycling is presented. Scrap classes and ways for the utilization of new scrap, post consumer scrap, residues and magnesium alloy scrap containing valuable alloying elements like rare earth and lithium are proposed. 相似文献