Cu-assisted austenite reversion and enhanced TRIP effect in maraging stainless steels

M. C. Niu, K. Yang, J. H. Luan, W. Wang, Z. B. Jiao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Control of the formation and stability of reverted austenite is critical in achieving a favorable combination of strength, ductility, and toughness in high-strength steels. In this work, the effects of Cu precipitation on the austenite reversion and mechanical properties of maraging stainless steels were investigated by atom probe tomography, transmission electron microscopy, and mechanical tests. Our results indicate that Cu accelerates the austenite reversion kinetics in two manners: first, Cu, as an austenite stabilizer, increases the equilibrium austenite fraction and hence enhances the chemical driving force for the austenite formation, and second, Cu-rich nanoprecipitates promote the austenite reversion by serving as heterogeneous nucleation sites and providing Ni-enriched chemical conditions through interfacial segregation. In addition, the Cu precipitation hardening compensates the strength drop induced by the formation of soft reverted austenite. During tensile deformation, the metastable reverted austenite transforms to martensite, which substantially improves the ductility and toughness through a transformation-induced plasticity (TRIP) effect. The Cu-added maraging stainless steel exhibits a superior combination of a yield strength of ∼1.3 GPa, an elongation of ∼15%, and an impact toughness of ∼58 J.

Original languageEnglish
Pages (from-to)52-58
Number of pages7
JournalJournal of Materials Science and Technology
Volume104
DOIs
Publication statusPublished - 30 Mar 2022

Keywords

  • Austenite reversion
  • Cu-rich nanoprecipitate
  • Maraging stainless steel
  • TRIP effect

ASJC Scopus subject areas

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Polymers and Plastics
  • Metals and Alloys
  • Materials Chemistry

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