4.7 Article

Measurement and prediction of the transformation strain that controls ductility and toughness in advanced steels

Journal

ACTA MATERIALIA
Volume 200, Issue -, Pages 246-255

Publisher

PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2020.08.028

Keywords

-

Funding

  1. European Research Council Advanced Grant Predictive Computational Metallurgy, ERC [339081 - PreCoMet]
  2. European Research Council Advanced Grant Multiaxial and Multiscale Plasticity in Metals, ERC [339245 - MULTIAX]
  3. EFPL

Ask authors/readers for more resources

New-generation multi-phase martensitic steels derive their high strength from the body-centered cubic (BCC) phase and high toughness from transformation of the metastable face-centered cubic (FCC) austenite that transforms into martensite upon loading. In spite of its critical importance, the in-situ transformation strain (or shape deformation tensor), which controls ductility and toughness, has never been measured in any alloy where the BCC lath martensite forms and has never been connected to underlying material properties. Here, we measure the in-situ transformation strain in a classic Fe-Ni-Mn alloy using high-resolution digital image correlation (HR-DIC). The experimentally obtained results can only be interpreted using a recent theory of lath martensite crystallography. The predicted in-situ transformation strain agrees with the measurements, simultaneously demonstrating the method and validating the theory. Theory then predicts that increasing the FCC to BCC lattice parameter ratio substantially increases the in-situ transformation strain magnitude. This new correlation is demonstrated using data on existing steels. These results thus establish a new additional basic design principle for ductile and tough alloys: control of the lattice parameter ratio by alloying. This provides a new path for development of even tougher advanced high-strength steels. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available