We elucidate here the phenomenological understanding of deformation mechanisms over a wide range of strain rates (5.5 × 10–4s–1 to 5.5 × 10–1s–1) based on the evolution of microstructure. Atom probe tomography (APT), transmission electron microscopy (TEM) and electron back-scattered diffraction (EBSD) experiments were conducted to reveal the spatial distribution of precipitates and microstructure evolution. The ordered kappa-carbides were characterised by a layered-type structure, which made it difficult for dislocations to by-pass kappa-carbides in the same layer individually and the corresponding strengthening mechanism was cutting mechanism. Dislocations and microbands evolution analysis shows that compared to dislocations, slip band width was the key factor that governed the strength of the experimental steel at different strain rates.
YooJDParkKT.Microband-induced plasticity in a high Mn-Al-C light steel. Mater Sci Eng A. 2008;496:417–424.
2.
ChoiKSeoCHLeeHEffect of aging on the microstructure and deformation behavior of austenite base lightweight Fe-28Mn-9Al-0.8C steel. Scripta Mater. 2010;63:1028–1031.
3.
FromeyerGBrüxU.Microstructures and mechanical properties of high-strength Fe-Mn-Al-C light-weight TRIPLEX steels. Steel Res Int. 2006;77(9):627–633.
4.
KimHSuhDWKimNJ.Fe-Al-Mn-C lightweight structural alloys: a review on the microstructures and mechanical properties. Sci Technol Adv Mater. 2013;14(1):014205.
5.
RaabeDSpringerHGutierrez-UrrutiaIAlloy design, combinatorial synthesis, and microstructure-property relations for low-density Fe-Mn-Al-C austenitic steels. JOM. 2014;66(9):1845–1856.
6.
SutouYKamiyaNUminoRHigh-strength Fe-20Mn-Al-C-based alloys with low density. ISIJ Int. 2010;50(6):893–899.
7.
WeiLLGaoGHKimJUltrahigh strength-high ductility 1 GPa low density austenitic steel with ordered precipitation strengthening phase and dynamic slip band refinement. Mater Sci Eng A. 2022;838:142829.
8.
DingHHanDCaiZHMicrostructures and mechanical behavior of Fe-18Mn-10Al-(0.8-1.2)C steels. JOM. 2014;66(9):1821–1827.
9.
ZambranoOA.A general perspective of Fe-Mn-Al-C steels. J Mater Sci. 2018;53:14003–14062.
10.
YooJDHwangSWParkKT.Origin of extended tensile ductility of a Fe-28Mn-10Al-1C steel. Metall Mater Trans A. 2009;40A:1520–1523.
11.
HwangSWJiJHLeeEGTensile deformation of a duplex Fe-20Mn-9Al-0.6C steel having the reduced specific weight. Mater Sci Eng A. 2011;528:5196–5203.
12.
SpringerHRaabeD.Rapid alloy prototyping: compositional and thermos-mechanical high throughput bulk combinatorial design of structural materials based on the example of 30Mn-1.2 C-xAl triplex steels. Acta Mater. 2012;60(12):4950–4959.
13.
ParkKT.Tensile deformation of low-density Fe-Mn-Al-C austenitic steels at ambient temperature. Scripta Mater. 2013;68:375–379.
14.
Gutierrez-UrrutiaIRaabeD.Multistage strain hardening through dislocation substructure and twinning in a high strength and ductile weight-reduced Fe-Mn-Al-C steel. Acta Mater. 2012;60:5791–5802.
15.
AllainSChateauJPBouazizOCorrelations between the calculated stacking fault energy and the plasticity mechanisms in Fe-Mn-C alloys. Mater Sci Eng A. 2004;387–389:158–162.
16.
Kuhlmann-WilsdorfD.Q: dislocations structures – how far from equilibrium? A: very close indeed. Mater Sci Eng A. 2001;315:211–216.
17.
ChenSRanaRHaldarACurrent state of Fe-Mn-Al-C low density steels. Prog Mater Sci. 2017;89:345–391.
18.
ChaoCYHwangLKLiuTF.Spinodal decomposition in Fe-9.0Al-30.5Mn-xC alloys. Scripta Metall. 1993;29:647–650.
19.
HuangHGanDKaoPW.Effect of alloying additions on the k phase precipitation in austenitic Fe-Mn-Al-C alloys. Scripta Metall Mater. 1994;30:499–504.
20.
TsayGDTuanYHLinCLEffect of carbon on spinodal decomposition in Fe-26Mn-20Al-C alloys. Mater Trans. 2011;52:521–525.
21.
WelschEPongeDHaghighatSHStrain hardening by dynamic slip band refinement in a high-Mn lightweight steel. Acta Mater. 2016;116:188–199.
22.
KimSHKimHKimNJ.Brittle intermetallic compound makes ultrastrong low-density steel with large ductility. Nature. 2015;518:77–79.
23.
YangHKZhangZJTianYZNegative to positive transition of strain rate sensitivity in Fe-22Mn-0.6C-x(Al) twinning-induced plasticity steels. Mater Sci Eng A. 2017;690:146–157.
24.
MisraRDKChallaVSAVenkatsuryaPKCInterplay between grain structure, deformation mechanisms and austenite stability in phase-reversion-induced nanograined/ultrafine-grained austenitic ferrous alloy. Acta Mater. 2015;84:339–348.
25.
YangHKTianYZZhangZJDifferent strain rate sensitivities between Fe-22Mn-0.6C and Fe-30Mn-3Si-3Al twinning-induced plasticity steels. Mater Sci Eng A. 2016;655:251–255.
26.
LiZZhaoSDiaoHHigh-velocity deformation of Al0.3CoCrFeNi high-entropy alloy: remarkable resistance to shear failure. Sci Rep. 2017;7:42742.
27.
ZhongNWangXDWangLEnhancement of the mechanical properties of a Nb-microalloyed advanced high-strength steel treated by quenching–partitioning–tempering process. Mater Sci Eng A. 2009;506:111–116.
28.
HuangHYangGZhaoGEffect of Nb on the microstructure and properties of Ti-Mo microalloyed high-strength ferritic steel. Mater Sci Eng A. 2018;736:148–155.
29.
KarmakarABiswasSMukherjeeSEffect of composition and thermo-mechanical processing schedule on the microstructure, precipitation and strengthening of Nb-microalloyed steel. Mater Sci Eng A. 2017;690:158–169.
30.
LiuRDLiYZLinLStrain rate sensitivity of a 1.5 GPa nanotwinned steel. J Iron Steel Res Int. 2021;28:1352–1356.
31.
ParkJMMoonJBaeJWStrain rate effects of dynamic compressive deformation on mechanical properties and microstructure of CoCrFeMnNi high-entropy alloy. Mater Sci Eng A. 2018;719:155–163.
32.
Kuhlmann-WilsdorfDWilsdorfHWertJ.LEDS theory of work hardening stages and “planar” versus “distributed” glide. Scripta Mettall Mater. 1994;31(6):729–734.
33.
KocksUMeckingH.Physics and phenomenology of strain hardening: the FCC case. Prog Mater Sci. 2003;48(3):171–273.
34.
RenXQLiYGQiYFEffect of micro-alloyed/alloyed elements on microstructure and properties of Fe-Mn-Al-C lightweight steel. Metals (Basel). 2022;12:695.
35.
LuoZCHuangMX.The role of interstitial carbon atoms on the strain-hardening rate of twinning-induced plasticity steels. Scripta Mater. 2020;178:264–268.
36.
KimSDParkJYParkSJDirect observation of dislocation plasticity in high-Mn lightweight steel by in-situ TEM. Sci Rep. 2019;9:15171.
37.
YaoMJWelschEPongeDStrengthening and strain hardening mechanisms in a precipitation-hardened high-Mn lightweight steel. Acta Mater. 2017;140:258–273.
38.
FisherJHartEPryR.Theory of slip-band formation. Phys Rev. 1952;87(6):958–961.
39.
KimJLeeS-JDe CoomanBC.Effect of Al on the stacking fault energy of Fe-18Mn-0.6C twinning-induced plasticity. Scripta Mater. 2011;65:363–366.
40.
LiangZYWangXHuangWStrain rate sensitivity and evolution of dislocations and twins in a twinning-induced plasticity steel. Acta Mater. 2015;88:170–179.
