Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK.
Sci Rep. 2017 Aug 29;7(1):9667. doi: 10.1038/s41598-017-10273-6.
First principles calculations are performed on ZrAlC and CrAlC MAX phases to compare their ability to accommodate point defects under irradiation. Interatomic bonding is stronger in CrAlC than ZrAlC but contrary to expectation ZrAlC exhibits higher vacancy and antisite pair formation energies. However, interstitials and Frenkel defects are generally more difficult to form in CrAlC. The results are attributed to the mixed covalent/ionic/metallic nature of the bonding. Detailed comparison of all the energies suggests that the preferred defects in ZrAlC and CrAlC are the V+Al Frenkel and Cr+Al antisite respectively. Thus the potential response of the two phases to irradiation is different and taking account of other competing defects it is suggested that ZrAlC is less susceptible to amorphization.
采用第一性原理计算方法对 ZrAlC 和 CrAlC MAX 相进行了计算，以比较它们在辐照下容纳点缺陷的能力。CrAlC 中的原子间键合比 ZrAlC 更强，但出人意料的是，ZrAlC 表现出更高的空位和反位缺陷形成能。然而，间隙原子和弗伦克尔缺陷在 CrAlC 中通常更难形成。这些结果归因于键合的混合共价/离子/金属性质。对所有能量的详细比较表明，ZrAlC 和 CrAlC 中的优先缺陷分别是 V+Al 弗伦克尔和 Cr+Al 反位缺陷。因此，两种相的辐照响应不同，考虑到其他竞争缺陷，ZrAlC 不易非晶化。
