arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1502.01138cond-mat.mtrl-sci
收藏

Mg-Y-Zn三元合金热力学稳定性的第一性原理研究

Thermodynamic stability of Mg-Y-Zn ternary alloys through first-principles

Ryohei Tanaka, Koretaka Yuge

摘要:

为了阐明Mg基长周期堆垛有序结构(LPSO)的热力学稳定性,基于特殊的准随机结构(SQS),系统地研究了Mg、Y和Zn元素随机混合时,不同成分的多层堆垛合金的能量偏好.通过对SQS形成自由能的计算,发现Mg-Y-Zn合金发生了富Mg相和富Y-Zn相的相分离,这与前人的理论研究结果相一致。SQS对于多种组成、堆叠序列和原子构型的体积模量范围在35 GPa左右,即,它们没有显示出显著的Mg浓度依赖性,因此这意味着声子的影响对LPSO相稳定性没有显著的作用。在hcp堆积中引入层错会获得“负”能量,这表明层错的引入与长周期堆积有序的形成有着深刻的关系。

英文摘要:

In order to clarify thermodynamic stability of Mg-based long-period stacking ordered (LPSO) structure, we systematically study energetic preference for alloys on multiple stacking with different composition for random mixing of constituent elements, Mg, Y, and Zn based on special quasirandom structure (SQS). Through calculation of formation free energy of SQS, Mg-Y-Zn alloy exhibits phase separation into Mg- and Y-Zn rich phase, which is consistent with previous theoretical studies. Bulk modulus of SQSs for multiple compositions, stacking sequences, and atomic configuratons ranges around 35 GPa, i.e., they do not show significant dependence of Mg concentration, which therefore means that the effects of phonon do not play significant role on LPSO phase stability. Introducing stacking fault to hcp stacking gains "negative" energy, which indicates profound relationship between introducing stacking faults and the formation of long-period stacking ordering.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑