First principle calculation of non-metallic inclusions properties in steel
Based on the first principle calculation,the crystal structural properties,electronic properties and mechan-ical properties of non-metallic inclusions in steel were studied.The structural stability of non-metallic inclusions was evaluated from the microscopic point of view.The influence of non-metallic inclusions on the mechanical properties of steel was revealed.The results show that absolute value of binding energy is the largest and structure is the most stable of TiN,followed by SiO2 and Al2O3.The absolute values of binding energy for MnS,Cu2O,CuO and FeO are low,the chemical bonds between atoms are weak,and the structures are relatively unstable.The band structure analysis shows that Al2O3,CaO,MgO,SiO2,AlN,MgAl2O4,Ca2SiO4 and CaAl4O7 belong to insulating materi-als,Cu2O,CaS and MnS belong to semiconductor materials,FeO,CuO,FeS and TiN belong to conductor materi-als.The results of elastic properties calculation show that the elastic modulus and hardness of TiN are the largest,which are 517.70 GPa and 31.77 GPa,respectively,indicating that TiN inclusions are brittle inclusions with high rigidity and strong resistance to deformation or failure.The elastic modulus and hardness of Cu2O are the smallest,which are 25.06 GPa and 0.24 GPa,respectively,indicating that Cu2O is plastic inclusion.The elastic modulus and hardness of composite non-metallic inclusion CaAl4O7 are 124.58 GPa and 5.52 GPa,respectively,and plastic de-formation ability is relatively poor,which are semi-plastic inclusion.The results of G/B(the ratio of bulk modulus to shear modulus)and Poisson's ratio show that the deviation of G/B value for SiO2 from 0.57 is the largest,and the Poisson's ratio is the smallest,which is 0.02,the inclusion is brittle.The maximum Poisson's ratio of Cu2O is 0.46,combined with its elastic modulus and hardness,its elastic properties are better.The results provide theoreti-cal basis and data support for the reasonable control of non-metallic inclusions in steel.
NETL
NSTL
万方数据
