(Ti1-xNbx)5AlC4(x=0.4, 0.75, 1)固溶体系的第一性原理研究

采用第一性原理计算，通过投影缀加波(PAW)和广义梯度近似(GGA)研究三元层状化合物(MAX) Ti₅AlC₄中Nb多比例掺杂M位元素.通过计算该固溶体系的声子谱、生成焓和弹性常数，讨论了(Ti_1-xNb_x)₅AlC₄固溶体系的稳定性，得到了三种稳定的结构：(Ti_0.6Nb_0.4)₅AlC₄、(Ti_0.25Nb_0.75)₅AlC₄和Nb₅AlC₄,即(Ti_1-xNb_x)₅AlC₄(x=0.4, 0.75, 1)固溶体系.Bader电荷、局域电荷密度、态密度表明该固溶体系呈现出金属特性，且电导率随着掺杂比例的增大，电荷不断转移，电导率增强.通过计算不同掺...

First-principles study on solid solution system of (Ti1-xNbx)5AlC4(x=0.4, 0.75, 1)

First-principles calculations were used to study the multi-proportion doping of Nb substituting for M in the ternary layered compound (MAX) Ti5AlC4 by Projector Augmented Wave (PAW) and Generalized Gradient Approximation (GGA). By calculating the phonon spectrum, formation enthalpy and elastic constant of the solid solution systems, the stabilities of the (Ti1-xNbx)5AlC4 solid solution systems were discussed, and three stable structures were obtained: (Ti0.6Nb0.4)5AlC4, (Ti0. 25Nb0.75)5AlC4 and Nb5AlC4, namely (Ti1-xNbx)5AlC4 (x=0.4, 0.75, 1) solid solution systems. Bader charge, electron localization function, and density of states indicate that the solid solution systems exhibit metallic properties, and with the increase of the doping ratio, the charge is continuously transferred and the conductivity is enhanced. The mechanical properties of the solid solution systems were discussed by calculating the elastic moduli and Vickers hardnesses of different doping ratios.