Computational material design for Q&P steels with plastic instability theory

G. Cheng, K. S. Choi, X. H. Hu, X. Sun

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

The ultimate tensile strength (UTS) and uniform elongation (UE) of quenching and partitioning (Q&P) steels under tension were examined with a combined theoretical, experimental and computational approach. The constituent phase properties of various Q&P steels were first estimated based on in situ high-energy X-ray diffraction (HEXRD) tensile tests under the quasi-static strain rate and room temperature. Plastic instability theory with the rule of mixtures (ROM) was then applied to the obtained phase properties to estimate the UTS/UE of the Q&P steels. A parametric study was also performed to examine the effects of various material parameters on the UTS/UE of Q&P steels. Computational material design was subsequently conducted based on the information obtained from the parametric study. The results showed that the plastic instability theory with iso-stress-based ROM may be used to estimate the UEs of the evaluated Q&P steels. The results also indicated that higher austenite stability/volume fractions, less strength difference between the primary phases, and higher hardening exponents of the constituent phases are generally beneficial for performance improvement of Q&P steels, and various material parameters may be concurrently adjusted in a cohesive way to improve performance of Q&P steel.

Original languageEnglish
Pages (from-to)526-538
Number of pages13
JournalMaterials and Design
Volume132
DOIs
StatePublished - Oct 15 2017
Externally publishedYes

Keywords

  • Material design
  • Multiphase advanced high strength steels
  • Plastic instability theory
  • Quenching and partitioning steels
  • Rule of mixtures

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