Processing and properties of magnesium containing a dense uniform dispersion of nanoparticles
Processing and properties of magnesium containing a dense uniform dispersion of nanoparticles
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DOI：
10.1038/nature16445
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发表时间：
2015-12-24
期刊：
影响因子：
64.8
通讯作者：
Li, Xiao-Chun
中科院分区：
文献类型：
--
作者：
Chen, Lian-Yi;Xu, Jia-Quan;Li, Xiao-Chun
镁是一种轻金属，密度是铝的三分之二，在地球上储量丰富，具有生物相容性；因此，它具有提高航空航天、汽车、国防、移动电子和生物医学应用的能源效率和系统性能的潜力（1-5）。然而，传统的合成和加工方法（合金化和热机械加工）在进一步改善镁和其他金属的性能方面已经达到了一定的极限(6)。陶瓷颗粒已被引入金属基体中以提高金属的强度(7)，但不幸的是，陶瓷微粒严重降低了金属的塑性和可切削性(7)，而纳米颗粒虽然具有在保持甚至改善金属塑性的同时提高强度的潜力（8,9），但难以均匀地分散在金属基体中（10-14）。在这里，我们表明，通过纳米颗粒在熔融金属中的自稳定机制，可以在镁中实现致密均匀的碳化硅纳米颗粒分散（按体积计为14%）。同时实现强度、刚度、塑性和高温稳定性的增强，比几乎所有结构金属提供更高的比屈服强度和更高的比模量。
Magnesium is a light metal, with a density two-thirds that of aluminium, is abundant on Earth and is biocompatible; it thus has the potential to improve energy efficiency and system performance in aerospace, automobile, defence, mobile electronics and biomedical applications(1-5). However, conventional synthesis and processing methods (alloying and thermomechanical processing) have reached certain limits in further improving the properties of magnesium and other metals(6). Ceramic particles have been introduced into metal matrices to improve the strength of the metals(7), but unfortunately, ceramic microparticles severely degrade the plasticity and machinability of metals(7), and nanoparticles, although they have the potential to improve strength while maintaining or even improving the plasticity of metals(8,9), are difficult to disperse uniformly in metal matrices(10-14). Here we show that a dense uniform dispersion of silicon carbide nanoparticles (14 per cent by volume) in magnesium can be achieved through a nanoparticle self-stabilization mechanism in molten metal. An enhancement of strength, stiffness, plasticity and high-temperature stability is simultaneously achieved, delivering a higher specific yield strength and higher specific modulus than almost all structural metals.