The mechanical behaviour and fracture were studied in a Fe–5Mn–2.5Al–0.2C (in wt-%) Medium Mn steel. Metallographic and magnetic measurements confirm the significant influence of the transformation kinetics of the strain-induced martensite on the mechanical properties and strain heterogeneities (Lüders and Portevin-Le Chatelier-like phenomena). An accurate study of isothermal evolutions of the microstructure, associated with atomistic calculations, complements current thermodynamic databases to quantify the nature and volume fraction of phases at different temperatures. A kinetic approach then predicts the influence of annealing conditions on the composition of retained austenite, key parameter for the martensitic transformation kinetics. This supports quantitative modelling of the influence of the intercritical annealing temperature on the ultimate tensile strength for industrial developments of these new grades.
MatlockD, SpeerJ.Third generation of AHSS: microstructure design Concepts. In: HaldarA, SuwasS, BhattacharjeeD, editors. Microstructure and texture in steels. London: Springer; 2009. p. 185–208.
2.
SuhD-W, ParkS-J, LeeT-H, Influence of Al on the microstructure evolution and mechanical behavior of low-carbon, manganese transformation-induced plasticity steel. Metall Mater Trans A. 2010;41A:397–408. doi:10.1007/s11661-009-0124-7.
3.
DingR, DaiZ, HuangM, Effect of pre-existed austenite reversion and mechanical behavior of an Fe-0.2C-8Mn-2Al medium Mn steel. Acta Mater. 2018;147:59–69. doi:10.1016/j.actamat.2018.01.009.
4.
SteinederK, KrizanD, SchneiderR, On the microstructural characteristics influencing the yielding behavior of ultra-fine grained medium-Mn steels. Acta Mater. 2017;139:39–50. doi:10.1016/j.actamat.2017.07.056.
5.
HeBB, LiangZY, HuangMX.Nanoindentation investigation on the initiation of yield point phenomenon in a medium Mn steel. Scripta Mater. 2018;150:134–138. doi:10.1016/j.scriptamat.2018.03.015.
6.
FrommeyerG, DrewesEJ, EnglB.Physical and mechanical properties of iron-aluminium-(Mn, Si) lightweight steels. Rev Métall. 2000;97:1245–1253. doi: 10.1051/metal:2000110
7.
SohnSS, LeeB-J, LeeS, Effect of annealing temperature on microstructural modification and tensile properties in 0.35 C–3.5 Mn–5.8 Al lightweight steel. Acta Mater. 2013;61:5050–5066. doi:10.1016/j.actamat.2013.04.038.
8.
SongH, SohnSS, KwakJ-H, Effect of austenite stability on microstructural evolution and tensile properties in intercritically annealed medium-Mn lightweight steels. Metall Mater Trans A. 2016;47A:2674–2685. doi:10.1007/s11661-016-3433-7.
9.
ZhouN, SongR, SongR, Influence of Nb addition on microstructure and mechanical properties of medium-Mn low-density steels. Steel Res Int. 2018;89:1700552. doi: 10.1002/srin.201700552
10.
HanHN, OhCS, KimG, Design method for TRIP-aided multiphase steel based on a microstructure-based modelling for transformation-induced plasticity and mechanically induced martensitic transformation. Mater Sci Eng A. 2009;499:462–468. doi:10.1016/j.msea.2008.09.026.
11.
ArlazarovA, GounéM, BouazizO, Evolution of microstructure and mechanical properties of medium Mn steels during double annealing. Mater Sci Eng A. 2012;542:31–39. doi:10.1016/j.msea.2012.02.024.
12.
WangXG, WangL, HuangMX.Kinematic and thermal characteristics of Lüders and Portevin-Le Châtelier bands in a medium Mn transformation-induced plasticity steel. Acta Mater. 2017;124:17–29. doi:10.1016/j.actamat.2016.10.069.
13.
WangX, HuangM.Temperature dependence of Lüders strain and its correlation with martensitic transformation in a medium Mn transformation-induced plasticity steel. J Iron Steel Res Int. 2017;24:1073–1077. doi: 10.1016/S1006-706X(17)30156-5
14.
LeeS, De CoomanBC.Effect of the intercritical annealing temperature on the mechanical properties of 10Pct Mn multi-phase steel. Metall Mater Trans A. 2014;45A:5009–5016. doi:10.1007/s11661-014-2449-0.
15.
SunB, VanderesseN, FazeliF, Discontinuous strain-induced martensite transformation related to the Portevin-Le Chatelier effect in a medium manganese steel. Scripta Mater. 2017;133:9–13. doi:10.1016/j.scriptamat.2017.01.022.
16.
FieldDM, Van AkenDC.Dynamic strain aging phenomena and tensile response of medium-Mn TRIP steel. Metall Mater Trans A. 2018;49A:1152–1166. doi:10.1007/s11661-018-4481-y.
17.
LeeS, LeeSJ, KumarSS, Localized deformation in multiphase, ultra-fine-grained 6 Pct Mn transformation-induced plasticity steel. Metall Mater Trans A. 2011;42A:3638–3651. doi:10.1007/s11661-011-0636-9.
18.
RobautF, CrisciA, Durand-CharreM, Practical aspects of carbon content determination in carburized steels by EPMA. Microsc Microanal. 2006;12:331–334. doi:10.1017/S1431927606060466.
19.
BeeseAM, MohrD.Identification of the direction-dependency of the martensitic transformation in stainless steel using in-situ magnetic permeability measurements. Exper Mech. 2011;51:667–676. doi:10.1007/s11340-010-9374-y.
20.
RaduM, ValyJ, GourguesAF, Continuous magnetic method for quantitative monitoring of martensitic transformation in steels containing metastable austenite. Scripta Mater. 2005;52:525–530. doi:10.1016/j.scriptamat.2004.10.034.
Mballa-MballaF, HubertO, LazregS, Multidomain modelling of the magneto-mechanical behaviour of dual-phase steels. Proceeding of the 18th World Conf. on Non-Destructive Testing (WCNDT 2012); 2012 Apr. 16–20; Durban, South Africa. British Institute of Non-Destructive Testing (BINDT); 2012.
CallahanM, HubertO, HildF, Coincidence of strain-induced TRIP and propagative PLC bands in medium Mn steels. Mater Sci Eng A. 2017;704:391–400. doi:10.1016/j.msea.2017.08.042.
25.
TomicevcZ, HildF, RouxS.Mechanics-aided digital image correlation. J Strain Anal Eng Des. 2013;48:330–343. doi:10.1177/0309324713482457.
26.
CaillardD.Dynamic strain ageing in iron alloys: the shielding effect of carbon. Acta Mater. 2016;112:272–284. doi:10.1016/j.actamat.2016.04.018.
27.
GibbsPJ, De MoorE, MerwinMJ, Austenite stability effects on tensile behavior of manganese-enriched-austenite transformation-induced plasticity steel. Metall Mater Trans A. 2011;42A:3691–3702. doi:10.1007/s11661-011-0687-y.
28.
TonizzoQ.Lien microstructure-comportement à rupture d'aciers de troisième génération à structure duplex pour application automobile [Relationship between microstructure and fracture behavior of 3rd generation steels with a duplex microstructure for automotive applications] [dissertation]. Paris: PSL Research University – Mines ParisTech; 2017. French.
29.
CallahanM.Analysis of transformation kinetics and strain instabilities in 3rd generation Medium Manganese TRIP steels [dissertation]. Paris: University Paris-Saclay – CentraleSupélec; 2017. Available from: https://tel.archives-ouvertes.fr/tel-01687833.
30.
CallahanM, PerladeA, SchmittJH.Origins of negative strain rate sensitivity and dynamic strain aging in 3rd generation AHSS; 2018.
31.
SunB, FazeliF, ScottC, Microstructural characteristics and tensile behavior of medium manganese steels with different manganese additions. Mater Sci Eng A. 2018;729:496–507. doi:10.1016/j.msea.2018.04.115.
32.
ZhangY, WangL, FindleyKO, Influence of temperature and grain size on austenite stability in medium manganese steels. Metall Mater Trans A. 2017;48A:2140–2149. doi:10.1007/s11661-017-3995-z.
33.
TekoğluC, HutchinsonJW, PardoenT.On localization and void coalescence as a precursor to ductile fracture. Phil Trans Roy Soc A. 2015;373:20140121. doi:10.1098/rsta.2014.0121.
34.
OlsonGB, AzrinM.Transformation behaviour of TRIP steels. Army Materials and Mechanics Research Center, Report TR 77-25; October 1977.
35.
CaillardD.A TEM in situ study of alloying effects in iron. II– Solid solution hardening caused by high concentrations of Si and Cr. Acta Mater. 2013;61:2808–2827. doi:10.1016/j.actamat.2013.01.049.
GoretskiiGP, GorevKV.Phase equilibria in Fe-Mn-Al-C. Russian Metall. 1990;2:217–221.
38.
LiMC, ChanH, KaoPW, The effect of Mn and Al contents on the solvus of κ phase in austenitic Fe-Mn-Al-C alloys. Mater Chem Phys. 1999;59:96–99. doi:10.1016/S0254-0584(99)00026-7.
39.
RigaudV, DalozD, DrilletJ, Phases equilibrium study in quaternary iron-rich Fe-Al-Mn-C alloys. ISIJ Int. 2007;47:898–906. doi:10.2355/isijinternational.47.898.
40.
KimMS, KangYB.Development of thermodynamic database for high Mn high Al steels: phase equilibria in the Fe-Mn-Al-C system by experiment and thermodynamic modelling. Calphad. 2015;51:89–103. doi:10.1016/j.calphad.2015.08.004.
41.
MestralletA.Thermodynamique de nouvelles solutions d'aciers de 3ème génération à structure duplex [Thermodynamics of new solutions for 3rd generation steels with a duplex microstructure] [dissertation]. Grenoble: Université Grenoble Alpes; 2017. French. Available from: https://tel.archives-ouvertes.fr/tel-01819772.
Gonzales-OrmenoPG, PetrilliHM, SchonCG.Ab initio calculation of the bcc Fe-Al phase diagram including magnetic interactions. Scripta Mater. 2006;54:1271–1276. doi:10.1016/j.scriptamat.2005.12.024.
44.
KresseG, FurthmüllerJ.Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comp Mater Sci. 1996;6:15–50. doi: 10.1016/0927-0256(96)00008-0
45.
KresseG, FurthmüllerJ.Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys Rev B. 1996;54:11169–11186. doi:10.1103/PhysRevB.54.11169.
46.
MurrayJL.Fe–Al binary phase diagram. In: BakerH., editor. Alloy Phase Diagrams. Materials Park ( OH USA: ASM International; 1992. p. 54.
47.
DequekerJ.Modélisation à l’échelle atomique du système Fe-Al-Mn-C à l'aide de modèles de paires et de calculs thermodynamiques [Atomistic modeling of the Fe-Al-Mn-C system using pairs model and thermodynamic calculations] [dissertation]. Lille: Université de Lille; 2018. French.
48.
MOB2 Mobility Database and Thermo-Calc AB. Stockholm (Sweden); 1999.
49.
EmoJ, MaugisP, PerladeA.Austenite growth and stability in medium Mn, medium Al Fe-C-Mn-Al steels. Comp Mater Sci. 2016;125:206–217. doi:10.1016/j.commatsci.2016.08.041.
50.
Van BohemenSMC.Bainite and martensite start temperature calculated with exponential carbon dependence. Mater Sci Technol. 2012;28:487–495. doi:10.1179/1743284711Y.0000000097.
51.
MahieuJ, MakiJ, De CoomanBC, Phase transformation and mechanical properties of Si-free CMnAl transformation-induced plasticity-aided steel. Metall Mater Trans A. 2002;33:2573–2580. doi:10.1007/s11661-002-0378-9.
52.
YangHS, SuhDW, BhadeshiaHKDH, More complete theory for the calculation of the martensite-start temperature in steels. ISIJ Int. 2012;52:164–166. doi:10.2355/isijinternational.52.164
53.
KoistinenDP, MarburgerRE.A general equation prescribing the extent of the austenite-martensite transformation in pure iron-carbon alloys and plain carbon steels. Acta Metall. 1959;7:59–60. doi:10.1016/0001-6160(59)90170-1.
54.
PerladeA, ZhuK.Toward a better understanding of mechanical properties in medium Mn TRIP steels. Proceedings of the HMnS Conference; 2016 Nov 16–18; Chengdu, China. The Chinese Society for Metals & Central Iron and Steel Institute; 2016; Paper D2-03 p. 619–623.
55.
KaufmanL, CohenM.Thermodynamics and kinetics of martensitic transformations. Prog Met Phys. 1958;7:165–246. doi:10.1016/0502-8205(58)90005-4.
56.
OlsonGB, CohenM.General mechanism of martensitic nucleation. 1. General concepts and FCC-HCP transformation. Metall Trans A. 1976;7:1897–1904. doi:10.1007/BF02659822.
57.
PatelJR, CohenM.Criterion for the action of applied stress in the martensitic transformation. Acta Metall. 1953;1:531–538. doi:10.1016/0001-6160(53)90083-2.
58.
AllainS, BouazizO.Microstructure based modelling for the mechanical behavior of ferrite-pearlite steels suitable to capture isotropic and kinematic hardening. Mater Sci Eng A. 2008;496:329–336. doi:10.1016/j.msea.2008.06.009.
