Outstanding Tensile Properties and Their Origins in Twinning-Induced Plasticity (TWIP) Steels with Gradient Substructures
| Autor: | Zhihui Guo, Stoichko Antonov, Huihui Zhi, Yanjing Su, Cheng Zhang |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
twinning-induced plasticity (TWIP) steels strength ductility gradient substructures Twip Plasticity lcsh:Technology Article Ultimate tensile strength General Materials Science Composite material lcsh:Microscopy Strengthening mechanisms of materials lcsh:QC120-168.85 lcsh:QH201-278.5 lcsh:T lcsh:TA1-2040 Hardening (metallurgy) Substructure lcsh:Descriptive and experimental mechanics lcsh:Electrical engineering. Electronics. Nuclear engineering Dislocation lcsh:Engineering (General). Civil engineering (General) lcsh:TK1-9971 Electron backscatter diffraction |
| Zdroj: | Materials Materials; Volume 13; Issue 5; Pages: 1184 Materials, Vol 13, Iss 5, p 1184 (2020) |
| Popis: | The low yield strength (~300 MPa) of twinning-induced plasticity (TWIP) steels greatly limits their structural applications in the industrial field. Conventional strengthening mechanisms usually cause an enhancement of yield strength but also a severe loss of ductility. In this research, gradient substructures were introduced in the Fe-22Mn-0.6C TWIP steels by different pre-torsional deformation in order to overcome the above limitations. The substructure evolution, mechanical properties, and their origins in gradient-substructured (GS) TWIP steels were measured and compared by electron backscattered diffraction (EBSD), monotonous and loading-unloading-reloading (LUR) tensile tests. It was found that a simple torsional treatment could prepare gradient twins and dislocations in coarse-grained TWIP steel samples depending on torsional strain. The uniaxial tensile tests indicated that a superior combination of high yield strength, high ultimate strength, and considerable ductility was simultaneously obtained in the GS samples. The high yield strength and high ultimate tensile strength were attributed to synergetic strengthening mechanisms, viz., dislocation strengthening, due to the accumulation of high density of dislocations, and very high back stress strengthening due to gradient substructure distribution, which was accommodated through pile-ups of extra geometrically necessary dislocations (GNDs) across the sample-scale. Additionally, high ductility originated from gradient substructure-induced back stress hardening. The present study is also beneficial to the design efforts of high strength and high ductility of other heterogeneous-structured TWIP alloy systems. |
| Databáze: | OpenAIRE |
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