Analysis of the Valence Electron Structures of the Strengthening Phases Al8Fe4Ce and Al4Ce in Al-Fe-Ce Alloy

Based on the empirical electron theory of solids and molecules (EET), the valence electron structures (VESs) of the strengthening phases Al8Fe4Ce and Al4Ce in Al-Fe-Ce alloy were calculated, then the relationships between the VESs and strengthening, stability of the alloy and grain refining were analyzed. The results show that the distribution of the bond network of Al8Fe4Ce is uniform, the third and the fourth bonds in the bond network of Al4Ce is the weakest segment of the whole bond network structure, and the strongest bond in the bond network of Al8Fe4Ce and Al4Ce is stronger than that of the matrix of the alloy. The VES of Al8Fe4Ce is favourable to stability of the alloy. During solidifying of the alloy, because the bonds formed by Ce atom and its adjacent atoms are all strong, that hinders Al atoms adjacent to Ce atom to involve in the growth of other grains and at the same time hinders the growth of the Ce atom group, so the structure of the alloy can be refined.