Microstructural evolution and strain hardening mechanism of a boron-containing metastable austenitic steel

Abstract

Quantitative tensile tests were carried out to study the microstructural evolution and strain hardening mechanism of a boron-containing metastable austenitic steel with 13 wt-% Mn and 0.30 wt-% B. The results indicate that the great mechanical properties come from two-stage TRIP effect and the true stress–strain curve can be divided into three stages during the tensile process. In the initial stage, part of the initial austenite transformed to ϵ-martensite through the stacking faults. Then, α’-martensite was formed from austenite directly or through the ϵ-martensite formation, which led to a great rise on the strain hardening rate in this stage. In the last stage, decline of the strain hardening rate was observed due to the co-work between multiple phases and voids.

KEYWORDS:

• Electron microscopy
• fracture mechanics
• micromechanics
• X-ray analysis
• phase transformation
• quantitative tensile tests
• metastable austenitic steel
• strain hardening mechanism

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability

The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an on-going study.

ORCID

Feng Li http://orcid.org/0000-0002-3224-8487

Additional information

Funding

This work was supported by National Natural Science Foundation of China: [Grant Number 51574028]; National Key Research and Development Program of Thirteenth Five-year Plan Period: [Grant Number 2017YFB0304400].