13th International Conference on Advanced Materials and Nanotechnology
Institute of Physics, ASCR, Prague, Czech Republic
The experimentally determined data – enthalpy and entropy – of the grain boundary segregation of substitutional solutes of 14th and 15th groups of the Periodic Table, i.e. silicon, phosphorus, tin and antimony, in α-iron are compared. The consequences of the grain boundary segregation of these elements for the intergranular strengthening or embrittlement are also shown and discussed from the point of view of the values of the segregation enthalpy and entropy. It is documented that all these solutes except silicon segregate at the grain boundaries interstitially at enhanced temperatures although substitutional segregation is preferred at zero K. It is shown that this controversy can be explained on basis of so called enthalpy-entropy compensation effect. Despite some variations, the values of the strengthening/embrittling Gibbs energy of all solutes are nearly linearly dependent on the differences in the sublimation energies of the host and solute.