2nd IPSUS Progress Meeting. 2nd IPSUS Progress Meeting FSW of ODS Steels. Rainer Lindau,, Michael Klimenkov, Anton Möslang, Michael Rieth.

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1 2nd IPSUS Progress Meeting FSW of ODS Steels Rainer Lindau,, Michael Klimenkov, Anton Möslang, Michael Rieth Courtesy TWI,Ltd. 1 9 nm 5 nm FSW was invented and patented by TWI, Ltd. in nm Y 2 O 3 2nd IPSUS Progress Meeting Outline Application of ODS steels in advanced Fusion Reactors other applications in advanced Nuclear Reactors (Gen IV) Production route of ODS steels Literature review on joining of ODS steels Own results on alternative joining techniques FSW trials on ODS-Eurofer Material procurement Microstructural examination of PM 2 Mechanical testing of PM 2 Tensile tests Impact tests 1 Rainer Lindau 2nd IPSUS Progress Meeting 1

2 Application of ODS steels in advanced Fusion Reactors Introduction 9% - 14% Cr reduced activation ODS steels are candidate materials for structural applications in advanced future fusion reactors Good irradiation properties high swelling resistance no HT He-embrittlement Good thermo-physical properties high thermal conductivity low thermal expansion Fast decay of radioactive inventory recycling, storage within reasonable time scale low level waste ~ 1 years Operational temperature window Blanket: ~ 25 C 55 C (EUROFER); ~ 65 C (ODS-EUROFER) Divertor: ~ 6 C 7 C (ODS RAFM/RAF steel) 2 Rainer Lindau 2nd IPSUS Progress Meeting Other applications in Nuclear Fission Reactors Introduction (ctd.) ODS steels are candidate materials for applications in advanced nuclear fission reactors (Gen IV) Cladding tubes for fuel pins in Liquid Metal Fast Breeder Reactors (LMFBR) Core components e.g. wrapper tubes Heat exchanger tubes 3 Rainer Lindau 2nd IPSUS Progress Meeting 2

3 Fusion Power Plants: Material Challenges Divertor: 1 dpa/a, 1-15 MW/m 2 Refractory alloys - e.g. W & W-alloys Dispersion strengthened steels - e.g. nano-composed RA-steels Blanket: 3 dpa/a, 2.5MW/m 2 Structural materials: - Reduced Activation Steels, ODS-Steels - V-alloys -SiC f /SiC Functional materials - Be: neutron multiplier - Li ceramics: T breeders 4 Rainer Lindau 2nd IPSUS Progress Meeting Model C: Modular design with permanent and exchangeable parts Power Plant Conceptual Studies European Model C He subsystems He-1 Pb-17Li coolant manifold hot shield cold shield a 176 blanket modules (a) (5-6 yrs. lifetime) 2 Pb-17Li 1 He-2 b 48 divertor plates (b) (1-2 yrs. lifetime) pol. rad. tor. ODS Layers plated to the FW EUROFER Structure (FW+Grids) SiCf/SiC channel inserts Dual Coolant He-PbLi LM Blanket Design T max 65 C, 8-15 dpa in DEMO P. Norajitra, FZK 5 Rainer Lindau 2nd IPSUS Progress Meeting 3

4 Production route of ODS steels Mechanical Alloying (MA) Hot Isostatic Pressing Fe Master Alloy Y 2 O 3 Powders Attrition Mill Steel can MA powder Heat Treatment Hot Rolling Hot Extrusion 6 Rainer Lindau 2nd IPSUS Progress Meeting Literature review Literature on FSW of ODS steels rather sparse Mainly other joining techniques reported Pulsed Laser Welding Electron Beam Welding Transient Liquid Phase Welding Inertia Friction Welding Resistance Pressure Welding Magnetic Pulse Welding Explosion Welding Recent Literature on FSW: Cole, Clark, Jue, Cullan; FSW of Ni-base ODS, (26) Tatlock, Al-Badeiry, Chen, Jones; FSW of PM 2, (26) Grant, Gelles, Steel, Lindau; FSW of ODS-Eurofer, (25) 7 Rainer Lindau 2nd IPSUS Progress Meeting 4

5 Tensile Properties diffusion welded ODS-Eurofer Eurofer joints Ultimate Tensile Strength R m [MPa] Yield Strength R p.2 [MPa] R m R p.2 EUROFER Heat Joint 6 ODS/EUROFER Joint 6 EUROFER base HIP Temperature 11 C PHHT 14 C 3' + 75 C 2h Ultimate Tensile Strength and Yield Strength of Joints almost identical to EUROFER 97 base Fracture never occurred in diffusion bond Good ductility from RT-7 C Test Temperature [ C] 8 Rainer Lindau 2nd IPSUS Progress Meeting Impact Properties diffusion welded ODS-Eurofer Eurofer joints Impact Energy A v [J] EUROFER 97 ODS-EUROFER notch area etched Test Temperature [ C] Diffusion Welded Joint HIP 11 C 3h 1 MPa PHHT 14 C 3 min + 75 C 2h Impact properties of joints closer to EUROFER 97 base than to ODS base material Alternative methods: Friction Stir Welding ODS Resistance Welding Magnetic Pulse Welding Resistance Welding also promising EUROFER 9 Rainer Lindau 2nd IPSUS Progress Meeting 5

6 Electron beam welding of ODS-Eurofer mm Post weld heat treatment: PWHT 1: as-welded + 98 C 3 WQ + 75 C 2h PWHT 2: as-welded PWHT 3: as-welded + 75 C 2h HAZ mm μm 1 Rainer Lindau 2nd IPSUS Progress Meeting Electron beam welding of ODS-Eurofer Tensile properties Ultimate Tensile Strength R m [MPa] R m ODS-EUROFER base material EB-weld 1, as-welded + 98 C 3' + 75 C 2h EB-weld 3, as-welded + 75 C 2h EUROFER Test Temperature [ C] 11 Rainer Lindau 2nd IPSUS Progress Meeting 6

7 Electron beam welding of ODS-Eurofer Tensile properties, Fractography R m of EB-welds comparable to strength of EUROFER 97 Very low total Elongation (<5%) Reduction of Area Z ~6% Deformation concentrates on welding zone Ductile fracture, Y 2 O 3 particles (2-5mm) in dimples Pores and inclusions 12 Rainer Lindau 2nd IPSUS Progress Meeting Electron beam welding of ODS-Eurofer Impact properties 1 EUROFER 97 Impact Energy A v [J] ODS-EUROFER base material ODS-EUROFER EB-welded 2 ODS-EUROFER, 6mm plate,.3 wt.-% Y 2 O 3 EB-weld 1, as-welded + 98 C 3' + 75 C 2h EB-weld 3, as-welded + 75 C 2h Rainer Lindau 2nd IPSUS Progress Meeting Test Temperature [ C] 7

8 Friction Stir Welding Trials of ODS-Eurofer (work at MegaStir, Inc. March 25) Grant, Gelles, Steel, Lindau; FSW of ODS-Eurofer, (25) Product form was flat plate 125mmx25mmx6mm Two bead on plate welds were made at two process conditions by Megastir Inc. using polycrystalline cubic boron nitride tooling with a 1 inch diameter tool with a.25 inch pin. Tool geometry was stepped spiral tool FSW in as received condition (hot rolled after HIPing no heat treatment) Weld No Weld Speed (cm/min) Spindle speed (rpm) Condition Peak Temperature ( C) No preheating No preheating 915 (Backside root forged into anvil slightly from pin that is too long) 14 Rainer Lindau 2nd IPSUS Progress Meeting Friction Stir Welding of ODS-Eurofer TEM examination Advancing side HAZ HAZ / TMAZ Recrystallized nugget Retreating side Typical FSW microstructure Minor defects present Advancing side defect from excessive pin length Some material stirred in from mild steel anvil at root TEM shows highly dislocated structure with dispersed 5 to 15 nanometer particles 15 Rainer Lindau 2nd IPSUS Progress Meeting 8

9 Friction Stir Welding of ODS-Eurofer Hardness measurements In these welds, nugget and TMAZ is harder than base material ODS Eurofer 97 #2 Nugget TMAZ HAZ Parent Rainer Lindau 2nd IPSUS Progress Meeting Material procurement No commercial producer for ODS steels in EU and USA Plansee has given up ODS production Not sufficient laboratory heats, e.g. ODS-Eurofer available Decision to use PM 2 instead of ODS-Eurofer for FSW trials PM 2 plate material from Plansee purchased mm thick plates 188 kg, ~ 4.2 m 2 Chemical composition of PM 2 and ODS-Eurofer: Cr W Ti V Al Ta Mn C Y 2 O 3 Fe PM balance ODS Eurofer balance 17 Rainer Lindau 2nd IPSUS Progress Meeting 9

10 TEM examination of PM 2 Analytical TEM (EDX) a) BF image of ODS particles b) Particle size distribution EDX-spectra of c) 4 μm 2 area d) Single ODS particle c) d) 18 Rainer Lindau 2nd IPSUS Progress Meeting TEM examination of PM 2 Analytical TEM (EFTEM) a) BF micrograph of area with ODS particles and EFTEM elemental maps taken with three windows method b) Fe-L 3,2 c) Y-M 5,4 d) O-K 19 Rainer Lindau 2nd IPSUS Progress Meeting 1

11 TEM examination of PM 2 X-ray spectra and HRTEM micrographs XRD-spectra of ODS particles, precipitations, and inclusions a) BF micrograph of YAG (Garnet, Y 3 Al 5 O 12 ) b) FFTF diagram c) YAP (Perovskite, YAlO 3 ) d) FFTF diagram 2 Rainer Lindau 2nd IPSUS Progress Meeting TEM examination of PM 2 Analytical TEM (EFTEM) Ti C Elemental distribution maps of inclusions BF micrograph and EFTEM elemental maps taken with three windows method Ti-L 2,3 C-K N-K N Y Al Y-M 4,5 Al-L 2,3 O-K O 21 Rainer Lindau 2nd IPSUS Progress Meeting 11

12 TEM examination of PM 2 HRTEM micrograph HR TEM micrograph of γ-al2o3 oriented with [11] zone axis M 22 Rainer Lindau 2nd IPSUS Progress Meeting Ultimate Tensile Strength R m of PM 2 compared to ODS-Eurofer and Eurofer steel 12 Ultimate Tensile Strength R m [MPa] R m ODS-EUROFER (.3 wt-% Y2 O 3 ) PM 2 EUROFER Test Temperature [ C] 23 Rainer Lindau 2nd IPSUS Progress Meeting 12

13 Total and Uniform Elongation of PM 2 compared to ODS-Eurofer and Eurofer steel Total Elongation A [%] A Uniform Elongation A g [%] A g Test Temperature [ C] ODS-EUROFER (.3 wt-% Y 2 O 3 ) Plate different thermo-mechanical treatments HIP as-received ODS-EUROFER (.5 wt-% Y 2 O 3 ) HIP different heat treatments PM2 EUROFER Ø1 24 Rainer Lindau 2nd IPSUS Progress Meeting Impact properties of PM 2 compared to ODS-Eurofer and Eurofer steel 1 EUROFER Impact Energy A v [J] ODS-EUROFER plate ODS-EUROFER HIP ODS-Eurofer,.3 wt.-% Y 2 O 3 HIP, as-received HIP + 11 C 3' + 75 C 2h plate, L-T, 98 C 3' + 75 C 2h 2 plate, T-L, 98 C 3' + 75 C 2h plate, L-T, 11 C 3' + 75 C 2h plate, T-L, 11 C 3' + 75 C 2h PM Test Temperature [ C] 2 nd Generation ODS-EUROFER PM 2 1 st Generation ODS-EUROFER 25 Rainer Lindau 2nd IPSUS Progress Meeting 13

14 Thank you very much for your attention! 26 Rainer Lindau 2nd IPSUS Progress Meeting 14