Abstract
Maraging steels are Fe-Ni precipitation-strengthened steels that can be heat treated for achieving high strength with an accompanying loss in ductility, a trend common to most metals. We show that the segregation of Ni during laser powder bed fusion, commonly considered a nuisance that is dealt with via solutionizing heat treatments, can be leveraged via direct aging to achieve higher strength and ductility simultaneously, compared to a solutionized and aged condition. The high dislocation density in combination with solute segregation in the as-fabricated material promotes the precipitation of Mo-rich intermetallic phases that are responsible for the high strength, and the Ni segregated regions facilitate austenite reversion during direct aging. The reverted austenite enhances the elongation via transformation-induced plasticity. While overcoming the strength–ductility conundrum, direct aging can significantly reduce the energy and emissions associated with multistep heat treatments, especially in the global tool and die industry, while laser powder bed fusion (LPBF) can enable tools with integrated cooling channels for increased downstream production efficiency.
| Original language | English |
|---|---|
| Pages (from-to) | 4221-4231 |
| Number of pages | 11 |
| Journal | JOM |
| Volume | 72 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 2020 |
Funding
Notice of copyright: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The US Government retains and the publisher, by accepting the article for publication, acknowledges that the US Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). P.N. and R.K. thank Ercan Cakmak and Chris Fancher from ORNL for XRD data acquisition. P.N. acknowledges Andrew Nguyen, AddUp Inc. for providing the LPBF samples used in this work. Research was performed at the US Department of Energy’s Manufacturing Demonstration Facility, located at Oak Ridge National Laboratory. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. Research was co-sponsored by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office. The Talos F200X S/TEM tool used in this work was provided by US DOE, Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities. P.N. and R.K. thank Ercan Cakmak and Chris Fancher from ORNL for XRD data acquisition. P.N. acknowledges Andrew Nguyen, AddUp Inc. for providing the LPBF samples used in this work. Research was performed at the US Department of Energy?s Manufacturing Demonstration Facility, located at Oak Ridge National Laboratory. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. Research was co-sponsored by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office. The Talos F200X S/TEM tool used in this work was provided by US DOE, Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities.
| Funders | Funder number |
|---|---|
| AddUp Inc. | |
| US Department of Energy?s Manufacturing Demonstration | |
| U.S. Department of Energy | |
| Advanced Manufacturing Office | |
| Office of Energy Efficiency and Renewable Energy | |
| Oak Ridge National Laboratory | DE-AC05-00OR22725 |
