A novel Fe–Cr–Ni–Co–Mo maraging stainless steel with enhanced strength and cryogenic toughness: Role of austenite with core-shell structures
Materials Science and Engineering: A(2023)
Abstract
Metastable austenite plays an important role in improving the cryogenic impact toughness of maraging steels by strain-induced martensitic transformations. However, a significant volume fraction of austenite decreases the yield strength of the material. In this study, to overcome the strength-toughness issue in maraging steels, austenite with a compositional core-shell structure and specific volume fraction are designed in Fe–Cr–Ni–Co–Mo maraging stainless steel. The core-shell compositional structure comprises retained austenite with bulk content in the core region and high Ni content reverted austenite layers in the shell region. During tensile testing, a step transformation of austenite with a continuous lattice is observed; herein, the shell regions are preserved. In contrast, the core regions transform to martensite. Close to the impact fracture, the thin austenite shell layers are retained from the martensitic transformation, which further contribute to the impact toughness. Under the combined influence of austenite and nanoprecipitates (Laves phase), the investigated alloy reaches a yield strength >1200 MPa at room temperature with good cryogenic impact toughness (77 K, >90 J), thereby outperforming conventional maraging steels and several high-entropy alloys. The current study demonstrates that the chemical heterogeneity within metastable austenite may create unique mechanical properties in structural materials.
MoreTranslated text
Key words
Maraging stainless steel,Retained austenite,Austenite reversion,Chemical heterogeneity,Precipitation
AI Read Science
Must-Reading Tree
Example
![](https://originalfileserver.aminer.cn/sys/aminer/pubs/mrt_preview.jpeg)
Generate MRT to find the research sequence of this paper
Chat Paper
Summary is being generated by the instructions you defined