A new concept in further alloying of Fe–Ni–Mn maraging steels

An Fe–10Ni–7Mn (wt.%) maraging steel is shown to suffer intergranular brittleness after aging due to discontinuous coarsening of grain boundary precipitates, associated with slip planarity accumulating high stress at grain boundaries. Microalloying with dilute additions of carbide-forming elements such as Nb and V as well as solid solution strengthening elements such as B was found to increase the grain boundary fracture stress remarkably. The beneficial effects of microalloying additions are attributed to hindering planar slip.