Kazuya Aizawa, Stefanus Harjo, Takuro Kawasaki, Wu Gong J-PARC Center, JAEA

TAKUMI @ 20 kW (2009)

@ 120 kW (2010)

-> macroscopic strain -> phase transformation -> texture -> non-uniform strain (dislocation, etc) -> crystallite size (grain boundaries, twinning, etc)

in situ

observation

of

microstructure

as average

bulk data

-> high intensity high resolution engineering diffractometer : TAKUMI

-> measurement with wide d-range (& multi scattering vector) : TOF instrument with multi banks

-> flexible data manipulation : event data recording method

-> sample environments : e.g. high temperature loading machine

information needed :

Nanobainitic isothermal process (-> slow process)

Thermo-mech. of 2Mn-0.2C steel (-> fast process)

Other possibilities using different sample environmental (SE) devices

vacuum (or inert gas)

Incident beam

Thermodilatometry

film austenite

Element C Si Mn Cr Mo Al Co

wt% 0.79 1.51 1.98 0.98 0.24 1.06 1.58

Bainitic process -> dilatation process starting, ending volume fraction data ? In situ diffraction microstructural evolution process starting, ending

0 5000 10000 15000 20000 25000 30000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

Bainitic ferrite

Film austenite

Bulk austenite

Volu

me fra

ctio

n

Time/s

■ Bainitic ferrite

● Film austenite

▲ Bulk austenite

300ºC

α`

γ

γ

α`:martensiteB:bainiteγ: austeniteγH:High carbon austeniteγL:Low carbon austenite2ºC/s

900ºC, 10min

Isothermal transformation at 400ºC

B+γH

+ γL

300ºC250ºC

200ºC

300sec

-5ºC/s

Bainitic transformation starts slowly depending on the isothermal temperature (diffusion of carbon)

Bulk dilatation is relevant to volume fraction of bainitic ferrite

High carbon content film austenite is also formed during bainitic transformation

Gauge size: Ø7mm x L7mm RT

900ºC, 600s

+10ºC/s

-2ºC/s

700ºC, ε = 0.15, 600s

-0.2ºC/s 620ºC, ε = 0.15, 120s

-0.2ºC/s

austenite

fcc

gamma

ferrite

bcc

alpha

austenite

fcc

gamma

ferrite

bcc

alpha

austenite

fcc

gamma

ferrite

bcc

alpha

10 s sliced diffraction data (axial dir.)

0 5000 10000 15000 20000 25000 30000 350000.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0

20

40

60

80

100

120

140

300C

250C

200C

DL(μm)

Vo

lum

e fr

act

ion

Time/s

Dilatometry

austenite -> ferrite transformation was accelerated by adding hot compression at 700ºC

Hot compression

sliced every 10s (500 hist.)

austenite -> ferrite transformation was accelerated by adding hot compression at 700ºC

Hot compression

sliced every 10s (500 hist.)

austenite -> ferrite transformation was slow at 700ºC

No hot compression

sliced every 30s (150 hist.)

austenite -> ferrite transformation was slow at 700ºC

No hot compression

sliced every 30s (150 hist.)

Thermo-mech. of a martensitic steel @ 300 kW (2013)

TOF = 31840 us

time = 2029.5 s

A martensitic steel was used. Heating to 900 C, cooling to 850 C, tensile deformation up to nominal strain of ~25% & unloading at 850 C, cooling. 2D pattern for the axial direction only obtained by slicing data per 1 second. 5mm slit and 5 mm radial collimators were used.

ganma-111

ganma-200

ganma-220

ganma-311

alpha-110

alpha-200

alpha-211

New device under development by CMSI of Kyoto Univ. Tsuji, Shibata, Oishi, et al.

Thermo-mechanical Simulation System

Highest temp: 1200 C Heating/cooling rate ≤ 30C/s Deformation rate ≤ 100 mm/s Vacuum or inert gas sample

anvils

induction coil

sample chamber

servo motor

Brought-in SE

80K chamber for deformation test

~80 K < temp. < 473 K Use liquid nitrogen for cooling To be added to loading machine

Tension up to 50 kN, compression up to 30 kN

Deformation rate ≤ 100 mm/min Load, displacement or strain control

Fatigue machine

Room temperature only Dynamic 50kN, static 60 kN

Fatigue rate < 30 Hz Tension and/or compression

Load, displacement or strain controll

Ultra-low temp. loading machine

Lowest temp: 7 K Below 20 K in ~ 3 hours

Tension only (can be used for comp. with special jig) Up 50 kN

Deformation rate ≤ 100 mm/min Load, displacement or strain control

delivered on March

under commissioning ready

Delivered until March 2014 Need commissioning during JFY 2014