title: Large recovery strain in Fe-Mn-Si-based shape memory steels obtained by engineering annealing twin boundaries.
abstract: Shape memory alloys are a unique class of materials that can recover their original shape upon heating after a large deformation. Ti-Ni alloys with a large recovery strain are expensive, while low-cost conventional processed Fe-Mn-Si-based steels suffer from a low recovery strain (<3%). Here we show that the low recovery strain results from interactions between stress-induced martensite and a high density of annealing twin boundaries. Reducing the density of twin boundaries is thus a critical factor for obtaining a large recovery strain in these steels. By significantly suppressing the formation of twin boundaries, we attain a tensile recovery strain of 7.6% in an annealed cast polycrystalline Fe-20.2Mn-5.6Si-8.9Cr-5.0Ni steel (weight%). Further attractiveness of this material lies in its low-cost alloying components and simple synthesis-processing cycle consisting only of casting plus annealing. This enables these steels to be used at a large scale as structural materials with advanced functional properties.
authors.affiliation: 1] College of Manufacturing Science and Engineering, Sichuan University, 610065 Chengdu, P.R. China [2] Max-Planck Institut für Eisenforschung, Max-Planck Strasse 1, 40237 Düsseldorf, Germany.
authors.forename: Y H
authors.initials: YH
authors.lastname: Wen
authors.affiliation: College of Manufacturing Science and Engineering, Sichuan University, 610065 Chengdu, P.R. China.
authors.forename: H B
authors.initials: HB
authors.lastname: Peng
authors.affiliation: Max-Planck Institut für Eisenforschung, Max-Planck Strasse 1, 40237 Düsseldorf, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Raabe
authors.affiliation: 1] Max-Planck Institut für Eisenforschung, Max-Planck Strasse 1, 40237 Düsseldorf, Germany [2] Research Center for Strategic Materials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba-city, Ibaraki 305-0047, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Gutierrez-Urrutia
authors.affiliation: College of Manufacturing Science and Engineering, Sichuan University, 610065 Chengdu, P.R. China.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Manufacturing Science and Engineering, Sichuan University, 610065 Chengdu, P.R. China.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Du