Novel ferrite-austenite duplex lightweight steel with 77% ductility by transformation induced plasticity and twinning induced plasticity mechanisms

Seok S Sohn, Kayoung Choi, Jai Hyun Kwak, Nack J. Kim, Sunghak Lee

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

The need for lightweight materials has been an important issue in automotive industries to reduce greenhouse gas emission and to improve fuel efficiency. In addition, automotive steels require an excellent combination of strength and ductility to sustain automotive structures and to achieve complex shapes, but the traditional approach to obtain a reduction in weight from down-gauged steels with high strength has many limitations. Here, we present a new ferrite-austenite duplex lightweight steel containing a low-density element, Al; this steel exhibits tensile elongation up to 77% as well as high tensile strength (734 MPa). The enhanced properties are attributed to the simultaneous formation of deformation-induced martensites and deformation twins and the additional plasticity due to deformation twinning in austenite grains having optimal mechanical stability. The present work gives a promise for automotive applications requiring excellent properties as well as reduced specific weight.

Original languageEnglish
Pages (from-to)181-189
Number of pages9
JournalActa Materialia
Volume78
DOIs
Publication statusPublished - 2014 Oct 1
Externally publishedYes

Keywords

  • Annealing
  • Duplex lightweight steel
  • Tensile properties
  • Transformation induced plasticity (TRIP)
  • Twinning induced plasticity (TWIP)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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