Advanced Study Group Ab Initio Based Modelling (ABM)
Designing Heusler nanoprecipitates by elastic misfit stabilization in Fe-Mn maraging steels
J. Millán, S. Sandlöbes, A. Al-Zubi, T. Hickel, P. Choi, J. Neugebauer, D. Ponge, D. Raabe.
Acta Materialia, 76, 94-105, (2014)
B2 NiMn and Ni2MnAl Heusler nanoprecipitates are designed via elastic misfit stabilization in Fe-Mn maraging steels by combining transmission electron microscopy (TEM) correlated atom probe tomography (APT) with ab initio simulations. Guided by these predictions, the Al content of the alloys is systematically varied, and the influence of the Al concentration on structure stability, size and distribution of precipitates formed during ageing at 450 degrees C is studied using scanning electron microscopy-electron backscatter diffraction, TEM and APT. Specifically, the Ni2MnAl Heusler nanoprecipitates exhibit the finest sizes and highest dispersion and hence lead to significant strengthening. The formation of the different types of precipitates and their structure, size, dispersion and effect on the mechanical properties of the alloys are discussed.
Keyword(s): Heusler nanoprecipitates; Maraging TRIP steels; Atom probe tomography; Transmission electron microscopy; Ab initio predictions