中国有色金属学报（英文版）
中國有色金屬學報（英文版）
중국유색금속학보（영문판）
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
2012年
3期
654-660
,共7页
CeAg%第一性原理%弹性常数%热力学性能
CeAg%第一性原理%彈性常數%熱力學性能
CeAg%제일성원리%탄성상수%열역학성능
CeAg%first-principle%elastic constant%thermodynamic property
采用第一性原理计算法研究具有B2(CsCl)结构的二元韧性金属间化合物CeAg的结构、力学性能、电子性质以及热力学性能.利用广义梯度近似计算得到的晶格常数为3,713 (A),比自旋密度近似计算的结果更符合实验值.负的形成能表明具有B2结构的CeAg是热力学稳定相.Ce和Ag原子的d能带相互分离导致两者的键合杂化作用较弱,从而阻止具有方向性的共价键形成.计算得到了CeAg的3个独立弹性常数(C11,C12和C44),体模量、剪切模量、弹性模量、各向异性因子以及泊松比分别为57.6 GPa、15.8 GPa、43.4 GPa、3.15和0.374.弹性常数符合所有力学稳定性准则.CeAg的Pugh判据值为3.65,当Pugh判据值大于1.75时,CeAg具有良好的韧性.此外,还计算和讨论了CeAg的体积、体模量、热容和热膨胀系数随温度或者压力的变化规律.
採用第一性原理計算法研究具有B2(CsCl)結構的二元韌性金屬間化閤物CeAg的結構、力學性能、電子性質以及熱力學性能.利用廣義梯度近似計算得到的晶格常數為3,713 (A),比自鏇密度近似計算的結果更符閤實驗值.負的形成能錶明具有B2結構的CeAg是熱力學穩定相.Ce和Ag原子的d能帶相互分離導緻兩者的鍵閤雜化作用較弱,從而阻止具有方嚮性的共價鍵形成.計算得到瞭CeAg的3箇獨立彈性常數(C11,C12和C44),體模量、剪切模量、彈性模量、各嚮異性因子以及泊鬆比分彆為57.6 GPa、15.8 GPa、43.4 GPa、3.15和0.374.彈性常數符閤所有力學穩定性準則.CeAg的Pugh判據值為3.65,噹Pugh判據值大于1.75時,CeAg具有良好的韌性.此外,還計算和討論瞭CeAg的體積、體模量、熱容和熱膨脹繫數隨溫度或者壓力的變化規律.
채용제일성원리계산법연구구유B2(CsCl)결구적이원인성금속간화합물CeAg적결구、역학성능、전자성질이급열역학성능.이용엄의제도근사계산득도적정격상수위3,713 (A),비자선밀도근사계산적결과경부합실험치.부적형성능표명구유B2결구적CeAg시열역학은정상.Ce화Ag원자적d능대상호분리도치량자적건합잡화작용교약,종이조지구유방향성적공개건형성.계산득도료CeAg적3개독립탄성상수(C11,C12화C44),체모량、전절모량、탄성모량、각향이성인자이급박송비분별위57.6 GPa、15.8 GPa、43.4 GPa、3.15화0.374.탄성상수부합소유역학은정성준칙.CeAg적Pugh판거치위3.65,당Pugh판거치대우1.75시,CeAg구유량호적인성.차외,환계산화토론료CeAg적체적、체모량、열용화열팽창계수수온도혹자압력적변화규률.
The first-principle calculations were performed to investigate the structural,mechanical,electronic and thermal properties of the binary ductile intermetallic compound CeAg with B2 (CsCl) structure.The calculated value of lattice constant a0 for CeAg with generalized gradient approximation is 3.713 (A),which is in better agreement with experimental data than local spin density approximation.The negative energy of formation implies that CeAg with B2 structure is thermodynamically stable phase.The greater separation betwcen the d bands of Ce and Ag results in weaker bond hybridization of Ce d-Ag d,which prevents formation of directional covalent bonding.The three indcpendent elastic constants (C11,C12 and C44) are derived and the bulk modulus,shear modulus,elastic modulus,anisotropy factor,and Poisson ratio are determined to be 57.6 GPa,15.8 GPa,43.4 GPa,3.15 and 0.374,respectively.The elastic constants meet all the mechanical stability criteria.The value of Pugh's criterion is 3.65.The ductility of CeAg is prcdicted if Pugh's criterion is greater than 1.75.Furthermore,the variations of volume,bulk modulus,heat capacity,and thermal expansion coefficient with temperature and/or pressure were calculated and discussed.
