Combining Gradient Structure and TRIP Effect to Produce Austenite Stainless Steel with High Strength and Ductility

By Xiaolei Wu, Muxin Yang, Fuh-Gwo Yuan, Longxin Chen, Yuntian Zhu. Heterostructured Materials, 2016

295 citations recorded by the source corpus.

Abstract 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 e-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 e-martensite walls. During tensile testing, the gradient structure causes strain partitioning, which evolves with applied strain, and lasts to large strains. The γ → α′ 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.

Subfields: Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/83b844cb46af640f2a867201d169672acb6b06fa

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In Materials Chemistry

1. Yuntian Zhu
2. Xiaolei Wu
3. T. Olugbade
4. Jian Lu
5. Chong-xiang Huang
6. Yusheng Li
7. Mingsai Wang
8. Yanfei Wang

In Mechanical Engineering

1. Yuntian Zhu
2. Xiaolei Wu
3. T. Olugbade
4. Jian Lu
5. Chong-xiang Huang
6. Yusheng Li
7. Mingsai Wang
8. R. Scattergood

Citations in the corpus

• Dense dispersed shear bands in gradient-structured Ni (2020, background): “As reported in gradient structured IF steel and CG/NS laminates, such strain gradient increase is known to lead to the accumulation of geometrically necessary dislocations and the development of back-stress work hardening (C. X. Huang et al., 2018; Li et al., 2017; Yang et al., 2016).”
• Literature review on the mechanical properties of materials after surface mechanical attrition treatment (SMAT) (2020, methodology): “Gradient structures in materials often lead to exceptional ductility, hardness and strength [112].”