Electric current induced precipitation in maraging steel

Maraging steel of grade 350 (Fe-18Ni-11.6Co-3.6Mo-1.2Ti-0.13Al in wt%) was subjected to pulsed electric current (electropulsing) at current densities ranging from 4 to 10 kA/mm(2). Hardness increased with increasing current density in the solutionized condition. Electropulsing did not alter the grain size, but did increase the local misorientation within grains. Differential scanning calorimetry and atom probe tomography confirmed the precipitation of Ni-3 (Ti, Mo). The temperature-time combination experienced by material due to joule heating was estimated to be insufficient for precipitation, and it was inferred that electric current inherently leads to an enhancement of precipitation kinetics. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.