Effect of the W addition content on valence electron structure and properties of MoSi2-based solid solution alloys

Based on the empirical electron theory (EET) of solids and molecules, the valence electron structures (VES) of MoSi2-based solid solution alloys have been analyzed using the average atom model. The results showed that with the increase of the W addition content, the hybridization steps of Mo and Si atom of the alloys occurred in C3 and 1, respectively. The hybridization step of W was always C5. The bond energy of the main bond branch, the covalence electron number on the strongest bond and the percentage of the total covalent electron numbers accounting for the total valence electron number of (Mo1−x, Wx)Si2 solid solutions increased with the increase of W addition content. These suggested that the addition of W would increase the melting point, hardness and strength and decrease the fracture toughness of (Mo1−x, Wx)Si2 solid solutions. Based on those results, MoSi2-based solid solution alloys were manufactured, and the results of the experiments were in accordance with those of the theory.