Title: Deformation mode and strain path dependence of martensite phase transformation in a medium manganese TRIP steel

Abstract

The martensite phase transformation dependence upon deformation modes and strain paths in a medium manganese (10 wt%) TRIP steel stamped into a T-shape panel was quantified through combination of 3D digital image correlation and synchrotron X-ray diffraction. The T-shape emulates a portion of a common anti-intrusion component. The stamping speed was kept intentionally slow (1 mm/s) so as to avoid excessive heat generation. The steel, which belongs to the third generation advanced high strength steel (3GAHSS) family, was chosen for two reasons: (1) it is two-phase, i.e. austenite and ferrite, with martensite resulting from deformation-induced phase transformation; (2) the 66 vot% initial retained austenite volume fraction (RAVF) enabled a thorough examination of the martensite phase transformation at large deformation levels without exhaustion. Strain fields were coupled with measured RAVF values of small specimens extracted from specific locations on a formed T-shape panel. This enabled an exploration of the effects of linear, bilinear, and non-linear strain paths as well as deformation modes such as tension, plane strain, biaxial tension, and equibiaxial tension. Results suggest a significant martensite phase transformation dependence on deformation mode and strain path in the absence of fracture and when martensite phase transformation is unaffected by heat generatedmore » during forming. In general, the uniaxial and biaxial tension deformation modes facilitate the martensite phase transformation, while the smallest amount of martensite phase transformation occurs under plane strain. Some discussion as to further application of the experimental methods detailed in this study to other 3GAHSS and the effects of fracture on martensite phase transformation is provided.« less

Authors:

Wu, Wei ^[1]; Wang, Yu-wei ^[1]; Makrygiannis, Panagiotis ^[1]; Zhu, Feng ^[1]; Thomas, Grant A. ^[1]; Hector, Louis G. ^[2]; Hu, Xiaohua ^[3]; Sun, Xin ^[4]; Ren, Yang ^[5]

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+ Show Author Affiliations

1. AK Steel Corp., Dearborn, MI (United States)
2. General Motors Corp., Warren, MI (United States)
3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
5. Argonne National Lab. (ANL), Argonne, IL (United States)

Publication Date:

Mon Nov 06 00:00:00 EST 2017

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

Contributing Org.:

AK Steel Corporation, Dearborn, MI (United States)

OSTI Identifier:

1435293

Alternate Identifier(s):

OSTI ID: 1413493; OSTI ID: 1473669; OSTI ID: 1549020

Report Number(s):

PNNL-SA-129061
Journal ID: ISSN 0921-5093; TRN: US1802837

Grant/Contract Number:  

AC05-00OR22725; AC02-06CH11357; EE0005976; AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing

Additional Journal Information:

Journal Volume: 711; Journal Issue: C; Journal ID: ISSN 0921-5093

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Deformation modes; Martensite phase transformation; Non-linear strain path; deformation modes; non-linear strain path