Dissimilar welding between oxide dispersion strengthened ferritic (ODS) steel and reduced activation martensitic steel would be required for constructing the advanced blanket of progressive fusion reactors. In this study, we achieved dissimilar joints by friction stir welding, and aimed to characterise and ameliorate joint inhomogeneity. Main results reveal that the joint inhomogeneity is generated from discrepant microstructural evolutions within the martensitic and ODS ferritic steels. The ODS steel achieves evolution by the dynamic recrystallisation, while the martensitic steel undergoes phase transformation that drastically hardens the stir zone. By a proper post-weld heat treatment, the joint inhomogeneity can be effectively ameliorated due to carbide reprecipitation and stress relief in the joint.
HübnerW.Phase transformations in austenitic stainless steels during low temperature tribological stressing. Tribol Int. 2001; 34(4):231–236. doi: 10.1016/S0301-679X(01)00006-8
2.
SuzukiT, KojimaH, SuzukiK, Plastic deformation and martensitic transformation in an iron-base alloy. Scr Metall. 1976; 10(4):353–358. doi: 10.1016/0036-9748(76)90091-0
3.
HanW, YabuuchiK, KimuraA, Effect of Cr/Al contents on the 475°C age-hardening in oxide dispersion strengthened ferritic steels. Nucl Mater Eng. 2016; 9:610–615.
HanW, ChenD, HaY, Modifications of grain-boundary structure by friction stir welding in the joint of nano-structured oxide dispersion strengthened ferritic steel and reduced activation martensitic steel. Scr Mater. 2015; 105:2–5. doi: 10.1016/j.scriptamat.2015.04.012
6.
PaninVE, EgorushkinVE, SurikovaNS, Shear bands as translation-rotation modes of plastic deformation in solids under alternate bending. Mater Sci Eng A. 2017; 703(Supplement C):451–460. doi: 10.1016/j.msea.2017.07.063
7.
GuoY, ChangY, ZhangJ, Microstructures and ion-irradiation behaviour of friction stir welded 12Cr-ODS steel. Sci Technol Weld Joining. 2017; 23(1): 1–8.
BhadeshiaH.Models for the elementary mechanical properties of steel welds. Book-Institute Mater. 1997; 650:229–284.
10.
ChungYD, FujiiH, SunY, Interface microstructure evolution of dissimilar friction stir butt welded F82H steel and SUS304. Mater Sci Eng A. 2011; 528(18):5812–5821. doi: 10.1016/j.msea.2011.04.023
11.
AlamoA, LambardV, AvertyX, Assessment of ODS-14%Cr ferritic alloy for high temperature applications. J Nucl Mater. 2004; 329–333:333–337. doi: 10.1016/j.jnucmat.2004.05.004
12.
YabuuchiK, TsudaN, KimuraA, Effects of tool rotation speed on the mechanical properties and microstructure of friction stir welded ODS steel. Mater Sci Eng A. 2014; 595:291–296. doi: 10.1016/j.msea.2013.12.022
13.
KimuraA, KasadaR, IwataN, Development of Al added high-Cr ODS steels for fuel cladding of next generation nuclear systems. J Nucl Mater. 2011; 417(1–3):176–179. doi: 10.1016/j.jnucmat.2010.12.300
14.
SchrammR, ReedR.Stacking fault energies of seven commercial austenitic stainless steels. Metall Mater Trans A. 1975; 6(7):1345–1351. doi: 10.1007/BF02641927
15.
ThomasB.Microscopic electronique et deformation plastique des aciers inoxydables austentiques industriels. J Microsc Spectrosc Electron. 1976; 1:623–626.
16.
HanW, KimuraA, TsudaN, Effects of mechanical force on grain structures of friction stir welded oxide dispersion strengthened ferritic steel. J Nucl Mater. 2014; 455(1–3):46–50. doi: 10.1016/j.jnucmat.2014.03.027
17.
BakerBW, MenonESK, McNelleyTR, Processing-Microstructure relationships in friction stir welding of MA956 oxide dispersion strengthened steel. Metall Mater Trans E. 2014; 1(4):318–330.
18.
HanW, UkaiS, WanF, Hardness and micro-texture in friction stir welds of a nanostructured oxide dispersion strengthened ferritic steel. Mater Trans JIM. 2012; 53(2):390–394. doi: 10.2320/matertrans.M2011226
19.
HanWT, WanFR, LengB, Grain characteristic and texture evolution in friction stir welds of nanostructured oxide dispersion strengthened ferritic steel. Sci Technol Weld Joining. 2011; 16(8):690–696. doi: 10.1179/1362171811Y.0000000064
20.
KozlovE, KiselevaS, PopovaN, Internal stresses and stored energy density in the grains at deformation of FCC-polycrystal. AIP Conference Proceedings, 2016, AIP Publishing, 020008.
21.
HumphreysF.A unified theory of recovery, recrystallization and grain growth, based on the stability and growth of cellular microstructures – I. The basic model. Acta Mater. 1997; 45(10):4231–4240. doi: 10.1016/S1359-6454(97)00070-0
22.
HumphreysF.A unified theory of recovery, recrystallization and grain growth, based on the stability and growth of cellular microstructures – II. The effect of second-phase particles. Acta Mater. 1997; 45(12):5031–5039. doi: 10.1016/S1359-6454(97)00173-0
23.
GourdetS, MontheilletF.Effects of dynamic grain boundary migration during the hot compression of high stacking fault energy metals. Acta Mater. 2002; 50(11):2801–2812. doi: 10.1016/S1359-6454(02)00098-8
24.
GourdetS, MontheilletF.An experimental study of the recrystallization mechanism during hot deformation of aluminium. Mater Sci Eng A. 2000; 283(1):274–288. doi: 10.1016/S0921-5093(00)00733-4
25.
HallbergH, WallinM, RistinmaaM.Modeling of continuous dynamic recrystallization in commercial-purity aluminum. Mater Sci Eng A. 2010; 527(4):1126–1134. doi: 10.1016/j.msea.2009.09.043
26.
ChangJ-K, TakataK, IchitaniK, Abnormal grain growth and recrystallization in Al-Mg alloy AA5182 following hot deformation. Metall Mater Trans A. 2010; 41(8):1942–1953. doi: 10.1007/s11661-010-0213-7
27.
BlumW, ZhuQ, MerkelR, Geometric dynamic recrystallization in hot torsion of Al 5Mg 0.6 Mn (AA5083). Mater Sci Eng A. 1996; 205(1–2):23–30. doi: 10.1016/0921-5093(95)09990-5
28.
McQueenH, KassnerM.Comments on ‘a model of continuous dynamic recrystallization’ proposed for aluminum. Scr Mater. 2004; 51(5):461–465. doi: 10.1016/j.scriptamat.2004.05.027
29.
MaZY, PilchakAL, JuhasMC, Microstructural refinement and property enhancement of cast light alloys via friction stir processing. Scr Mater. 2008; 58(5):361–366. doi: 10.1016/j.scriptamat.2007.09.062
30.
ChangCI, LeeCJ, HuangJC.Relationship between grain size and Zener–Holloman parameter during friction stir processing in AZ31 Mg alloys. Scr Mater. 2004; 51(6):509–514. doi: 10.1016/j.scriptamat.2004.05.043
31.
ZhangQ, XiaoBL, XueP, Microstructural evolution and mechanical properties of ultrafine grained Al3Ti/Al–5.5Cu composites produced via hot pressing and subsequent friction stir processing. Mater Chem Phys. 2012; 134(1):294–301. doi: 10.1016/j.matchemphys.2012.02.068
32.
XiaoBL, YangQ, YangJ, Enhanced mechanical properties of Mg–Gd–Y–Zr casting via friction stir processing. J Alloys Compd. 2011; 509(6):2879–2884. doi: 10.1016/j.jallcom.2010.11.147
33.
SatoYS, KokawaH, EnomotoM, Microstructural evolution of 6063 aluminum during friction-stir welding. Metall Mater Trans A. 1999; 30(9):2429–2437. doi: 10.1007/s11661-999-0251-1
