ON THE PROBLEM OF MARTENSITE TETRAGONALITY NATURE

Abstract

Despite the fact that scientists have been studying the nature of the mechanism of martensite formation for almost a hundred years, these studies remain, still, relevant. In this paper, the authors present two new results related to the classical question of the role of carbon in martensite formation. If, while dissolving in the lattice, the carbon is located in the center of the octahedral emptiness, then under the influence of stresses caused by quenching or deformation, in martensite it is displaced into one of the pyramids of the constituent octahedra. The fact of the independence of the specific atomic volume of phase mismatch during martensitic transformation of iron from the carbon content was found. This fact indicates that the tetragonality of carbon steels is a function not so much of carbon as vacancies. In the pure iron the "vacancy" tetragonality can vary from 1.03 to 1.06.

Keywords

• martensite transformation
• stress state
• tetragonality
• vacancies
• iron
• carbon