In order to illuminate the relationship between microstructure morphology and final properties of the quenching and partitioning(Q&P) steel, the samples with different microstructure morphology (equiaxed and lamellar) and same volume fraction of each phase are obtained by controlling the initial microstructure and Q&P heat treatment. Because of the feature of microstructure morphology, a large yield ratio and total elongation are obtained in the lamellar sample though yield strength and ultimate tensile strength are relatively lower than that of equiaxed sample. Moreover, the lamellar sample produces a continuous work-hardening rate and better the fracture toughness compared to the equiaxed sample. Thus the lamellar sample is more suitable to be used as automotive structural components.
SpeerJ, MatlockDK, De CoomanBC, Carbon partitioning into austenite after martensite transformation. Acta Mater. 2003;51:2611–2622. doi: 10.1016/S1359-6454(03)00059-4
2.
SpeerJG, EdmondsDV, RizzoFC, Partitioning of carbon from supersaturated plates of ferrite, with application to steel processing and fundamentals of the bainite transformation. Curr Opin Solid State Mater Sci. 2004;8:219–237. doi: 10.1016/j.cossms.2004.09.003
3.
De CoomanBC.Structure–properties relationship in TRIP steels containing carbide-free bainite. Curr Opin Solid State Mater Sci. 2004;8:285–303. doi: 10.1016/j.cossms.2004.10.002
4.
SpeerJG, De MoorE, FindleyKO, Analysis of microstructure evolution in quenching and partitioning automotive sheet steel. Metall Mater Trans A. 2011;42:3591–3601. doi: 10.1007/s11661-011-0869-7
5.
LiW, GaoH, NakashimaH, In-situ EBSD study of deformation behavior of retained austenite in a low-carbon quenching and partitioning steel via uniaxial tensile tests. Mater Charact. 2016;118:431–437. doi: 10.1016/j.matchar.2016.06.020
6.
SeoEJ, ChoL, De CoomanBC.Kinetics of the partitioning of carbon and substitutional alloying elements during quenching and partitioning (Q&P) processing of medium Mn steel. Acta Mater. 2016;107:354–365. doi: 10.1016/j.actamat.2016.01.059
7.
De KnijfD, PetrovR, FöjerC, Effect of fresh martensite on the stability of retained austenite in quenching and partitioning steel. Mater Sci Eng: A2014;615:107–115. doi: 10.1016/j.msea.2014.07.054
8.
SeoEJ, ChoL, EstrinY, Microstructure-mechanical properties relationships for quenching and partitioning (Q&P) processed steel. Acta Mater. 2016;113:124–139. doi: 10.1016/j.actamat.2016.04.048
9.
MandalG, GhoshSK, BeraS, Effect of partial and full austenitisation on microstructure and mechanical properties of quenching and partitioning steel. Mater Sci Eng: A2016;676:56–64. doi: 10.1016/j.msea.2016.08.094
10.
SugimotoK, MisuM, KobayashiM, Effects of second phase morphology on retained austenite morphology and tensile properties in a TRIP-aided dual-phase steel sheet. ISIJ Int. 1993;33:775–782. doi: 10.2355/isijinternational.33.775
11.
MarkA, WestphalM, BoydD, Microstructural design of multiphase advanced high strength steels. Can Metall Quart. 2009;48:237–245. doi: 10.1179/cmq.2009.48.3.237
12.
XiongXC, ChenB, HuangMX, The effect of morphology on the stability of retained austenite in a quenched and partitioned steel. Scripta Mater. 2013;68:321–324. doi: 10.1016/j.scriptamat.2012.11.003
13.
DingR, TangD, ZhaoA.A novel design to enhance the amount of retained austenite and mechanical properties in low-alloyed steel. Scripta Mater. 2014;88:21–24. doi: 10.1016/j.scriptamat.2014.06.014
14.
DingR, TangD, ZhaoA, Effect of intercritical temperature on quenching and partitioning steels originated from martensitic pre-microstructure. J Mater Res. 2014;29:2525–2533. doi: 10.1557/jmr.2014.285
15.
DingR, TangD, ZhaoA, A new type of quenching and partitioning processing developed from martensitic pre-microstructure. Mater Manuf Process2014;29:704–709. doi: 10.1080/10426914.2014.912304
16.
MatsumuraO, SakumaY, TakechiH.Enhancement of elongation by retained austenite in intercritically annealed 0.4C-1.5Si-0.8Mn steel. ISIJ Int. 1987;27:570–579. doi: 10.2355/isijinternational1966.27.570
DysonDJ, HolmesB.Effect of alloying additions on the lattice parameter of austenite. J Iron Steel Inst. 1970;208:469–474.
19.
Castro CerdaFM, SabirovI, GoulasC, Austenite formation in 0.2 C and 0.45 C steels under conventional and ultrafast heating. Mater Design. 2017;116:448–460. doi: 10.1016/j.matdes.2016.12.009
20.
SantofimiaMJ, ZhaoL, SietsmaJ.Microstructural evolution of a low-carbon steel during application of quenching and partitioning heat treatments after partial austenitization. Metall Mater Trans A. 2009;40A:46–57. doi: 10.1007/s11661-008-9701-4
21.
SantofimiaMJ, ZhaoL, PetrovR, Characterization of the microstructure obtained by the quenching and partitioning process in a low-carbon steel. Mater Charact. 2008;59:1758–1764. doi: 10.1016/j.matchar.2008.04.004
22.
Ghassemi-ArmakiH, MaaßR, BhatSP, Deformation response of ferrite and martensite in a dual-phase steel. Acta Mater. 2014;62:197–211. doi: 10.1016/j.actamat.2013.10.001
23.
HanJ, Da SilvaAK, PongeD, The effects of prior austenite grain boundaries and microstructural morphology on the impact toughness of intercritically annealed medium Mn steel. Acta Mater. 2017;122:199–206. doi: 10.1016/j.actamat.2016.09.048
24.
ChiangJ, LawrenceB, BoydJD, Effect of microstructure on retained austenite stability and work hardening of TRIP steels. Mater Sci Eng: A2011;528:4516–4521. doi: 10.1016/j.msea.2011.02.032
25.
ZhangS, FindleyKO.Quantitative assessment of the effects of microstructure on the stability of retained austenite in TRIP steels. Acta Mater. 2013;61:1895–1903. doi: 10.1016/j.actamat.2012.12.010
