Design and characterization of a cobalt-free stainless maraging steel for laser-based powder bed fusion
Journal article, 2022

This study presents a new Co-free stainless maraging variant for laser-based powder bed fusion developed using a computational alloy design approach. The goal was to develop an easily printable material with similar performance to 18Ni-300. After screening numerous compositions, Fe-13.2Cr-9.1Ni-1.1Al-0.6Mo-0.5Nb-0.23Ti-0.5Mn-0.5Si (wt.%) was selected. This composition showed excellent printability with low porosity levels. The precipitation strengthening response was evaluated by aging at 500 °C for 15 min, 3 h and 18 h, measuring hardness, tensile strength, and by characterization using atom probe tomography. After 15 min of aging, 90% of the maximum hardness was reached, thanks to formation of (Ni, Al, Nb, Ti, Mn, Si) clusters with a density of 1.5 × 1024 m-3. Between 15 min and 3 h, distinct precipitates formed with a radius of ∼1.4 nm. The precipitates underwent a splitting phenomenon after 18 h, forming several unique Ni-rich precipitates including Ni16Si7(Ti, Nb)6 and Ni3(Al, Ti, Nb, Si). The splitting can be a reason for the slow coarsening rate, as the average precipitate radius after 18 h was only 2 nm. Simulations of the precipitation sequence using PRISMA indicated very rapid and dense precipitation of L12-Ni3X precipitates with a slow coarsening rate, in agreement with experimental observations.

Precipitates

Alloy design

LB-PBF

Maraging

Additive

APT

Author

Dmitri Riabov

Chalmers, Industrial and Materials Science, Materials and manufacture

Karin Frisk

Chalmers, Industrial and Materials Science, Materials and manufacture

Mattias Thuvander

Chalmers, Physics, Microstructure Physics

Eduard Hryha

Chalmers, Industrial and Materials Science, Materials and manufacture

S. Bengtsson

Höganäs

Materials and Design

0264-1275 (ISSN) 1873-4197 (eISSN)

Vol. 223 111180

Subject Categories

Manufacturing, Surface and Joining Technology

Atom and Molecular Physics and Optics

Metallurgy and Metallic Materials

DOI

10.1016/j.matdes.2022.111180

More information

Latest update

10/27/2023