the eurofusion program on 9crwvta steels · 2015-12-14 · the eurofusion program on 9crwvta steels...

The EUROfusion program on 9CrWVTa

steels

M. Rieth, P. Fernandez, J. Henry, J. Hoffmann, L. Pilloni, A. Puype, N. de Wispelaere

Budget (w/o overheads)

2 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS

0

500

1000

1500

2000

2500

1 2 3 4 5

Hardware (EC/k€) Total Allocated2014-18

2300

2400

2500

2600

2700

1 2 3 4 5

Manpower (EC/k€) Total Allocated2014-18

Total Allocated Resources by RU

273 lab ppy 30 ind ppy

8.74 M€ hw

Overall Objectives 2014-2018


Fill gaps in the database and develop design codes for the baseline materials including irradiation data

Development of new materials to mitigate requirements of advanced DEMO component designs

Demonstration of the production of such materials in processes scalable to industrial standards

Characterization & Documentation of the properties of such materials

Develop models for neutron radiation effects, specifically microstructural evolution and embrittlement, in iron alloys, steels, tungsten, and degradation of functional materials


ODS steel: Fabrication & Demonstration Production of a 100 kg 14%Cr ODS steel batch by mechanical alloying

Plates: thickness 2 mm, size 2 m² Demonstration of applicability to first wall

Alternatives to mechanical alloying (feasibility studies and industrial large-scale fabrication)

Development of RAFM steels for high temperature applications Specific thermal treatments on EUROFER Special thermo-mechanical treatments (TMT) Fine tuning of the chemical composition

Optimization of RAFM steels for possible water cooling Specific thermal treatments (for optimum DBTT) Change of chemical composition (for optimum DBTT)

Advanced Steels (AS): Objectives

RAFM: Reduced Activating Ferritic-Martensitic

focus of this presentation

Effect of Extreme Heat Treatments: EUROFER


Z and Laves phases suspended

0,0001

0,001

0,01

0,1

1

500 700 900 1100 1300 1500 1700980 1050 1150 760

Mo

lar

ph

ase

fra

ctio

n

Temperature (°C)

Liquide

(V,Ta)(N,C)

M23C6

TaN-

(Ta,V,Cr)(C,N)

Advanced Steels: High Temp. Applications

Adjustment of EUROFER properties by varying heat treatment temperatures

• Austenitisation: 980 °C – 1150 °C • Tempering: 700 °C – 760 °C


Z and Laves phases suspended

0,0001

0,001

0,01

0,1

1

500 700 900 1100 1300 1500 1700980 1050 1150 760

Mo

lar

ph

ase

fra

ctio

n

Temperature (°C) 1250

Liquide

(V,Ta)(N,C)

M23C6

TaN-

(Ta,V,Cr)(C,N)

Effect of Extreme Thermo-Mechanical Treatments



Very high austenitization temperature for full dissolution of secondary phases Increase PAG size for improved creep strength (lower diffusion) Possible problem: Retain enough ductility at RT

Dissolution of all secondary phases (carbides, nitrides)

Cooling to rolling temperature in furnace (metastable

austenite phase)

Rolling in the austenite phase



Standard Heat Treatment

1050°C / 30min + 750°C / 2h

EUROFER

Very large prior austenite grains (0.5-1 mm) But fine martensite laths

1250°C/30 min + TMT at 800°C + 750°C / 2h

Extreme TMT

70 µm 70 µm



gain of ~ 50 MPa in strength

0 100 200 300 400 500 600 7000

100

200

300

400

500

600

yie

ld s

trength

[M

Pa]

Temperature [°C]

Eurofer 97-2 (993391)

600°C

700°C

800°C

900°C

as-received

Tensile Strength



Creep Strength

20000 h

+50 MPa +50 °C



DBTT Shift (Charpy)

Fine-tuning of Chemical Composition


Objective(s): 1. Selection a of chemical compositions of 9%Cr RAFM steels

with the aim of improving high temperature properties (creep and creep fatigue properties in particular) as compared to standard Eurofer.

2. Determination of the hot rolling temperature range by using the obtained phase diagrams.

Method(s): The modified chemical compositions will be obtained on the basis of thermodynamic calculations of Mx-(C,N)y phases in 9Cr(1-2W)VTa steels. Contents in C, N, Ta, V will be varied and the influence of W and Ti will be assessed. JMatPro & ThermoCalc Software



EUROFER97 89Fe-9Cr-1.1W-0.5Mn-0.2V-0.14Ta-0.1C-0.02N Fe88.7-Cr9.64-W0.33-Mn0.51-V0.22-Ta0.04-C0.46-N0.08



(CrFe)23C6

(FeCr)2W

Cr2TaVN2

V5N4

TaC

EUROFER97 89Fe-9Cr-1.1W-0.5Mn-0.2V-0.14Ta-0.1C-0.02N Fe88.7-Cr9.64-W0.33-Mn0.51-V0.22-Ta0.04-C0.46-N0.08



TEM studies on aged Eurofer samples

30000 h, 550-600 °C: no Laves phase Fe52Cr15W33

WCr

11 µm

Fe

Comparison and correction: Simulation - Reality



TEM studies on aged Eurofer samples

30000 h, 550-600 °C: Is there Z phase Cr2TaVN2 ?

Cr Ta Fe V Ta Fe

M23C6

TaC

VN

TaC

Precipitation map under development Provides correction parameters for simulation



minimum for martensite formation?

0.03 % C

0.05 % C

0.1 % C

0.02 % C

M2

3C

6 (

mo

le %

) Carbon



Lave

s (m

ole

%) 3 % W

2 % W

1.5 % W

1 % W

Tungsten



maximum for a complete alpha-gamma transition?

Au

ste

nit

e (

mo

le %

) Tungsten

3 % W

2 % W

1.5 % W

1 % W



P92 OPTIFER-IVa

EUROFER97 1538

Comparison/Correlation of known properties/alloys



o Reduction of M23C6 decrease of C content but ensure Martensite formation targets: 0.03 – 0.06 %

o VN: adjustment of amount and onset target: 0.4 – 0.6 % start of formation: about 1250 °C (solution annealing) by variation of V and N

o TaC: “adjustment” of onset target: below 0.2 % start of formation: below VN by variation of Ta

o Isolate/identify effects of single elements

Mn, Si – “further purification” by removal

W possible increase of strength by addition

o …

Strategies for optimization: some examples

Summary and present status

• More than 30 heats produced by industry (80 kg each)

• Development of a computational model for the selection

of 9%Cr RAFM steels optimized for high temperature

application (Genetic Algorithm)

• Mechanical properties & microstructural investigations

under way irradiation in 2016/17


• CCFE • CEA • CIEMAT (+ CEIT,

URJC, UPM, …) • DTU • ENEA-Frascati • ENEA-CNR • FZJ • Wigner RCP (HAS) • NCSRD (HELLENIC) • MPG (IPP) • IPPLM • IST • KIT • ISSP-UL (LATVIA) • IAP (MEdC) • JSI (MESCS) • FOM-DIFFER (NRG) • OEAW • RBI • LPP-ERM-KMS

(SCK.CEN) • UT (TARTU) • VTT (TEKES) • VR

Thank you !

MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS 24

the eurofusion program on 9crwvta steels · 2015-12-14 · the eurofusion program on 9crwvta steels...

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