The State Key Lab of High Performance Ceramics and Superfine Microstructure
Structural Ceramics Engineering Research Center
Simulation of mechanical properties of AlMgB14-based compounds
Speaker：Prof. Oleksiy Bystrenko
Institute for Problems in Materials Science, National Academy of Sciences of Ukraine
Lecture：Simulation of mechanical properties of AlMgB14-based compounds
First principle simulations of bulk moduli for a number of XYB14-compounds (X=Al,V,Nb,Ti,Ta; Y=Mg,N,C,Si,Sc,Ti,V,Cr,Y,Zr,Nb,W,Ta) were performed in order to determine the compositions with potentially better hardness. The calculations were carried out on the basis of stress-strain approach within the framework of density functional theory with the use of ultrasoft pseudopotentials and generalized gradient approximation of exchange-correlation energy. The results of simulations indicate that the moderate increase in bulk moduli is observed for the case of replacement of Mg-atom by transitional metals of III-V groups with partially occupied d-shell. Comparative study of electronic structure of AlMgB14 and AlTaB14 has revealed in this case significant contribution of d-electrons to density of states of valence band. The ways of accurate simulation of indentation process and hardness for multigrain composite materials on the basis of phase field models are discussed.