Kazuya Aizawa, Stefanus Harjo, Takuro Kawasaki, Wu Gong J-PARC Center, JAEA
in situobservation
ofmicrostructure
as averagebulk data
information needed :-> 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. hightemperature loading machine-> macroscopic strain-> phase transformation-> texture-> non-uniform strain(dislocation, etc)-> crystallite size
(grain boundaries,twinning, etc)

SiMn

CrMoAlCo

wt%

0.79

1.51

1.98

0.98

0.24

1.06

1.58

Incident
beam

γ-5ºC/s2ºC/sγα`:martensite
B:bainite
γ: austenite
γH:High carbon austenite
γL:Low carbon austenite

0.7
0.6

Isothermal transformation at 400ºC
300ºC

α`

B+γH+ γL

250ºC
200ºC

300secBainitic ferrite
Film austenite
Bulk austenite

1.1300ºC

1.0
0.9

vacuum (or inert gas)
Volume fraction

film austenite

Bainitic process -> dilatation
process starting, ending
volume fraction data ?
In situ diffraction
microstructural evolution
process starting, ending-2ºC/saustenite
fcc
gamma

0.6
0.5
0.405000

10000

15000

20000

25000

30000

Time/s

600.2

400.1

200.005000

10000 15000 20000 25000 30000 35000

Thermo-mech. of a martensitic steel@ 120 kW (2010)@ 300 kW (2013)

No hot compression

A martensitic steel was used.
Heating to 900 C, cooling to850 C, tensile deformation
up to nominal strain of ~25%
& unloading at 850 C, cooling.

ferritebcc
alpha

700ºC, ε = 0.15, 600s

RT0.3High carbon content film austenite is also
formed during bainitic transformation

0.0+10ºC/s-0.2ºC/s

80

Bulk dilatation is relevant to volume
fraction of bainitic ferrite

0.1

Hot compression

0.4

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

0.2

Thermodilatometry

100

Time/s0.3

Thermo-mech. of 2Mn-0.2C steel (-> fast process)900ºC, 600s

0.70.50■ Bainitic ferrite● Film austenite▲ Bulk austenite

0.8

Dilatometry
300C
140250C200C
120DL(μm)

CElement

900ºC, 10min

TAKUMI @ 20 kW (2009)

Volume fraction

Nanobainitic isothermal process (-> slow process)620ºC, ε = 0.15, 120s

2D pattern for the axial
direction only obtained byslicing data per 1 second.

-0.2ºC/s

Gauge size: Ø7mm x L7mm

TOF = 31840 ustime = 2029.5 sganma-111
alpha-110
ganma-200

alpha-200
ganma-220
ganma-311

alpha-211

5mm slit and 5 mm radialcollimators were used.

10 s sliced diffraction data (axial dir.)austenite -> ferrite transformation was
accelerated by adding hot compression at700ºC
sliced every 10s (500 hist.)austenite -> ferrite transformation wasslow at 700ºC
sliced every 30s (150 hist.)

New device under development by CMSI of Kyoto Univ.

Other possibilities using different sample environmental (SE) devices

Tsuji, Shibata, Oishi, et al.

Thermo-mechanical Simulation Systeminduction coilanvils

readydeliveredon March

Ultra-low temp. loadingmachine

80K chamber for
deformation test 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

 ~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 controlsample

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

Delivered until March 2014
Need commissioning during JFY 2014
under commissioning

Fatigue machine Room temperature only
 Dynamic 50kN, static 60 kN
 Fatigue rate < 30 Hz
 Tension and/or compression
 Load, displacement or strain controll

Brought-in SE

servo motor
sample chamber