Use of atom probe techniques to support thermodynamic and atomistic modelling of phase transformations

Atom probe field ion microscopy (APFIM) gives accurate data on phase composition for all elements and has a good sensitivity and excellent spatial resolution. APFIM data have therefore been used as support for thermodynamic modelling of phase equilibria and phase transformations. This paper describes a number of cases where atom probe data from Chalmers University have been used to judge the accuracy of modelling: the solubility of W and C in Co, the equilibrium volume fraction of VN in a complex chromium steel, the content of B in M23C6 precipitates, the growth of Laves phase during ageing of a chromium steel, and the growth of secondary NbC precipitates in a stabilised austenitic stainless steel. Atomistic modelling is now emerging as a tool for materials science, in particular for modelling of interfacial structure and energies. The status of the activities in this field at Chalmers University is described, and the role of APFIM in atomistic modelling is discussed.