Electronic structures and alloying behaviors of ferrite phases in high Co-Ni secondary hardened martensitic steels

The electronic structure of ferrite (tempered martensite phase) in high Co- Ni secondary hardened martensitic steel has been investigated. The local de nsity of states (LDOS) of alloying elements in the steel displays the relat ionship between solid solubility and the shape of the LDOS. The bond order integral (BOI) between atoms in the steel shows that the directional bondin g of the p orbital of Si or C leads to the brittleness of the steel. At las t, Sigma BOI between atoms demonstrate that C, Co, Mn, Cr, Mo, Si strengthe n the alloyed steel through solid-solution effects.