Abstract
Constitutive micromechanical behavior of transformation induced plasticity (TRIP) stainless steel (SS) alloys was investigated using high-energy synchrotron x-ray diffraction (S-XRD) and in-situ neutron diffraction techniques. First, four different steel alloys were designed and produced: (1) a metastable austenitic TRIP SS, (2) a stable austenitic SS, which is a stable counterpart of the TRIP SS, (3) a lean duplex TRIP SS with ferrite and metastable austenite phases, and (4) a lean duplex stable SS, which is a stable counterpart of duplex TRIP SS. Then, effects of chemical composition, microstructure, and texture on the plastic anisotropy, martensitic transformation kinetics, and residual stress concentration during a tensile deformation were investigated. The results show that the plastic anisotropy, governed by the initial microstructure and texture, has insignificant effect on macroscopic tensile properties and martensitic phase transformation kinetics despite different R-values observed along different loading directions. On the other hand, the interplay between stress partitioning among constituent phases and martensitic phase transformation plays a critical role in the micromechanics of plastic deformation, and, consequently, determines the distributions of in-situ martensite fraction and residual stresses. The phase stress partitioning in the TRIP alloy clearly shows that a large tensile residual stress of 1.8 GPa can concentrate on the martensite phase with 30% plastic strain. In contrast, the introduction of the tensile load-sharing ferrite phase in the cost-effective lean duplex TRIP alloy significantly reduces the tensile residual stress concentration in the martensite phase, which could improve the formability of high-strength TRIP steels.
| Original language | English |
|---|---|
| Article number | 100952 |
| Journal | Materialia |
| Volume | 15 |
| DOIs | |
| State | Published - Mar 2021 |
Funding
This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States 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 ). This research was funded by the U.S. National Science Foundation (NSF) Metals and Metallic Nanostructures (MMN) program under contract DMR-1308548. This research was also supported in part by POSCO Corp. South Korea. P. Hou and H. Choo acknowledge funding from the State of Tennessee and Tennessee Higher Education Commission (THEC) through their support of the Center for Materials Processing at the University of Tennessee. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States 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). This research was funded by the U.S. National Science Foundation (NSF) Metals and Metallic Nanostructures (MMN) program under contract DMR-1308548. This research was also supported in part by POSCO Corp., South Korea. P. Hou and H. Choo acknowledge funding from the State of Tennessee and Tennessee Higher Education Commission (THEC) through their support of the Center for Materials Processing at the University of Tennessee. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.
| Funders | Funder number |
|---|---|
| DOE Public Access Plan | |
| Metals and Metallic Nanostructures | DMR-1308548 |
| POSCO Corp | |
| POSCO Corp. | |
| U.S. National Science Foundation | |
| United States Government | |
| National Science Foundation | |
| U.S. Department of Energy | |
| Office of Science | |
| Argonne National Laboratory | DE-AC02-06CH11357 |
| Oak Ridge National Laboratory | DE-AC05-00OR22725 |
| University of Tennessee | |
| Tennessee Higher Education Commission |
Keywords
- Martensitic phase transformation
- Neutron and synchrotron x-ray diffraction
- Stress partitioning
- TRIP steel
- Texture