Highly complex materials processes as understood by phase-field simulations: Additive manufacturing, bainitic transformation in steel and high-temperature creep of superalloys

Abstract

Recent breakthroughs resolving open questions in materials science by phase-field simulations are reported. They relate to solidification structure formation in additive manufacturing, carbon redistribution during bainitic transformation, and the onset of damage during high-temperature creep of superalloys. The first example deals with the balance between epitaxial growth and nucleation in solidification. The second relates to the controversy regarding diffusion control and dominance of massive transformation in bainite transformation. The third relates to directional coarsening (rafting) in superalloys as a diffusion-controlled phase transformation: loss of coherency of precipitates marks the onset of damage associated with rotation of the crystal lattice and topological inversion. Technical details of the phase-field method are reviewed as necessary, and limitations of the approach are discussed.