Journal
ACTA MATERIALIA
Volume 112, Issue -, Pages 337-346Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2016.04.045
Keywords
Gradient structure; Strain hardening; Ductility; Transformation-induced plasticity; Strain partitioning
Funding
- National Natural Science Foundation of China (NSFC) [11572328, 11222224, 11472286]
- 973 Programs [2012CB932203, 2012CB937500, 6138504]
- US Army Research Office [W911 NF-12-1-0009]
- US National Science Foundation [DMT-1104667]
- Nanjing University of Science and Technology
Ask authors/readers for more resources
We report a design strategy to combine the benefits from both gradient structure and transformation induced plasticity (TRIP). The resultant TRIP-gradient steel takes advantage of both mechanisms, allowing strain hardening to last to a larger plastic strain. 304 stainless steel sheets were treated by surface mechanical attrition to synthesize gradient structure with a central coarse-grained layer sandwiched between two grain-size gradient layers. The gradient layer is composed of submicron-sized parallelepiped austenite domains separated by intersecting epsilon-martensite plates, with increasing domain size along the depth. Significant microhardness heterogeneity exists not only macroscopically between the soft coarse-grained core and the hard gradient layers, but also microscopically between the austenite domain and epsilon-martensite walls. During tensile testing, the gradient structure causes strain partitioning, which evolves with applied strain, and lasts to large strains. The gamma -> alpha' martensitic transformation is triggered successively with an increase of the applied strain and flow stress. Importantly, the gradient structure prolongs the TRIP effect to large plastic strains. As a result, the gradient structure in the 304 stainless steel provides a new route towards a good combination of high strength and ductility, via the co-operation of both the dynamic strain partitioning and TRIP effect. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available