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基于密度泛函理论,采用第一性原理赝势平面波方法计算了不同压力下L12-Co3(Al,W)化合物的弹性性质与电子结构。计算得到零压力下的点阵常数a0与实验值和理论值相符,计算结果表明:在0~45 GPa压力范围内,L12-Co3(Al,W)化合物的弹性常数Cij(C11、C12、C44)与压力满足三阶多项式关系,体模量B、剪切模量G、本征塑性、断裂韧性随压力的增强而增加;通过引入总化学键重叠布局数,定量的计算了金属间化合物的共价键性能,结果显示压力的增加会不断增强L12-Co3(Al,W)化合物中的共价键强度;电荷差分密度分析表明,随着压力的增加,W原子得到电子,Al原子失去电子,Co-Co、Co-W原子间电荷密度明显增强,表现出更强的键合作用。
Based on the density functional theory, the elastic properties and electronic structures of L12-Co3 (Al, W) compounds under different pressures were calculated by the first-principle pseudopotential plane wave method. The calculated lattice constant a0 under zero pressure is in agreement with the experimental and theoretical values. The calculated results show that the elastic constants Cij (C11, C12, C44) of compounds of L12-Co3 (Al, W) ) And the pressure satisfy the third-order polynomial relationship, the body modulus B, the shear modulus G, the intrinsic plasticity, and the fracture toughness increase with the increase of the pressure. By introducing the total number of chemical bonds overlapping layouts, the total amount of intermetallic compounds The results show that the increase of pressure will increase the covalent bond strength in L12-Co3 (Al, W) compounds. The charge density analysis shows that with the increase of pressure, W atoms get electrons, Al atoms lose electrons, Co-Co, Co-W atomic charge density was significantly enhanced, showing a stronger bond.