Mechanical properties of MAX phase thin films: The effect of band filling on the elastic properties of M2AlC thin Films (M=Ti, V, Cr)

Mn+1AXn相（其中M是早期过渡金属，A是A族元素，X是C或N， N =1-3）具有不同寻常的机械、化学、热学和电学性能组合。这种相当独特的性质的起源，即以前无法预见的金属和陶瓷属性的组合，是由于它们的纳米层化原子排列。虽然Barsoum及其同事1和其他人对Ti3SiC2的性质进行了比较好的描述，但有关结构相关化合物的合成和性质的许多基本材料科学问题仍未得到解答：其中一个实验未探索的问题是，211 MAX相中碳化物形成金属M的价电子构型对其弹性和塑性性能的依赖。M2AlC系统是根据我们最近发表的从头计算选择的。我们的策略是，一旦确定并优化了这些材料的合适生长条件，就可以将纳米压痕测量的机械性能与通过M2AlC中碳化物形成金属M的系统变化价电子构型的结构、化学和键合表征获得的信息联系起来。通过与已经发表的从头算数据的关联，我们期望对这类迷人的固体有更好的基本理解。

Mn+1AXn phases (where M is an early transition metal, A an A group element and X is either C or N, n=1-3) possess an unusual combination of mechanical, chemical, thermal and electrical properties. The origin of this rather unique set of properties, i.e. a previously unforeseen combination of metallic and ceramic Attributes is due to their nanolaminated atomic Arrangement. While the properties of Ti3SiC2 are comparatively well described by Barsoum and coworkers 1 and others, many basic materials science questions with respect to the synthesis and properties of structurally related compounds remain unanswered: One such experimentally unexplored question is the dependence of the elastic and plastic properties on the valence electron configuration of the carbide forming metal M in 211 MAX phases. The M2AlC system was selected based on our recently published ab initio calculations. Our strategy is, once suitable growth conditions for these materials are identified and optimized, to correlate the mechanical properties measured by nanoindentation with the information gained through structure, chemistry and bonding characterization for the systematically varied valence electron configuration of the carbide forming metal M in M2AlC. Through correlation with already published ab initio data we expect to contribute towards a better basic understanding of this fascinating class of solids.