First-principles studies on structure stability, segregation and work
function of Mg doped different metal elements
Abstract
The first-principles methods based on the density functional theory were
employed to study the structural stability, segregation and work
function of Mg doped with fourteen metal elements existing in human
body. The calculated results show that there is a simple correlation
between solid solution and segregation. Doping Sn, Y, Li, Gd, Nd, Sc and
Zn atoms have a negative formation energy as well as a positive
segregation energy. This suggests that these elements which are not
easier to be dissolved in Mg matrix tend to segregate on the Mg (0001)
surface. An opposite trend was observed for Ba, Fe, Mn, W, Sr, Ca and
Mo. On the other hand, the electronic work function of Mg (0001) surface
was increased significantly for doping Mo, W, Fe, and Mn, and was
reduced markedly for Ba, Ca and Sr. For Li, Sn, Sc, Gd, and Y, their
doping on Mg surface generate a relatively small change in work
function. In addition, the relationships of corrosion behavior to
segregation and work function were discussed. This study may provide an
avenue for seeking a more appropriate alloying element of Mg alloys with
improved corrosion resistance in biomedical applications.