First principle study on the effect of Cr, Mn and Ni on electronic structure and mechanical properties of high nitrogen steel

Based on the first principle method of density functional theory, the effects of alloying elements Cr, Mn and Ni on the electronic structure and mechanical properties of high nitrogen austenite were calculated. The alloying effects of alloying elements Cr, Mn and Ni in high nitrogen austenite were analysed from the aspects of cohesive energy, formation heat, electronic population and elastic constant. The results show that the alloy atoms Cr, Mn and Ni all preferentially occupy the top corner of the high nitrogen austenitic cell. The cohesive energy between Cr and the cell is the largest, the cell is the most stable, Mn is the second, and Ni is the lowest. The solid solution of Cr, Mn and Ni increases the strength of covalent bond and ionic bond in the system, which is the main reason for the performance improvement. Mn has the strongest interaction of ionic bond in high nitrogen austenite cell, and is an excellent austenite stable element. All alloy systems meet the mechanical stability criterion. After Cr and Ni are solid dissolved in high nitrogen austenitic cell, the strength and stiffness of the system decrease, and the plasticity and ductility increase. After Cr is solid dissolved, the corrosion resistance of the system can be significantly increased, and the strength, stiffness and brittleness of the system increased after Mn solid solution.