実験報告書様式（元素戦略）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）Experimental Report

承認日 Date of Approval
承認者 Approver
提出日 Date of Report

課題番号 Project No.

装置責任者 Name of Instrument scientist

2015E0001

BL:19: Kazuya Aizawa

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

In-situ Neutron Diffraction Analysis of Deformation and Phase

BL19

Transformation Behaviors of Advanced Structural Materials in

実施日 Date of Experiment

Elements Strategy Initiative for Structural Materials (ESISM)(1) 6/20-6/22, 2015

実験責任者名 Name of principal investigator(2) 5/16, 17, 19, 20, 2016

Nobuhiro Tsuji
所属 Affiliation
Kyoto University
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
(1) 6/20-6/22, 2015
Fe-2Mn-0.1C (wt. %), Fe-24Ni-6Al-0.4C (wt. %), Cu-40Zn (wt. %).
(2) 5/16, 17, 19, 20, 2016
Fe-2Mn-0.1C (wt. %), Fe-5Mn-2Si-0.1C (wt. %), Ti-6Al-4V (wt. %).

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

(1) 6/20-6/22, 2015
(1-1)
The cold-rolled Fe-24Ni-6Al-0.4C alloy exhibits extremely high strength but keeps reasonableelongation even in the as-rolled state.

In order to clarify the origin of the superior mechanicalproperties, we conducted in-situ neutron diffraction experiment during tensile deformation of
Fe-24Ni-6Al-0.4C alloys which were cold rolled with the reduction of 0 %, 50 %, and 81%.
As shown in the schematic illustration of Figure 1, a tensile test specimen was mounted at thestandard tensile testing system at BL19 TAKUMI as that the tensile axis to be aligned 45° with respect2. 実験方法及び結果（つづき） Experimental method and results (continued)
to the incident beam. The neutron diffraction patterns
in the axial and transversal directions were measured
simultaneously using two time-of-flight detector banks
that have the scattering angles of ± 90°.
Figure 2 shows in-situ neutron diffraction profiles
during tensile deformation of the 0 % cold-rolled
specimen.

The 0 % cold-rolled specimen before

tensile deformation consisted of austenite (FCC) andintermetallic particles (BCC base structure).

On theother hand, the peaks corresponding to martensite
began to appear after tensile strain of about 30%.
Figure 3 summarizes changes in fraction ofmartensite with increasing of the tensile strain.
foundthat

deformation-inducedWe

Figure 1 Schematic illustration showing analignment of a tensile test specimen withrespect to the incident and diffracted
neutron beam.

martensitic

transformation occurred during tensile deformationeven in the 50% and 81% cold-rolled specimens. Inaddition,

thefractions

ofdeformationinducedmartensite in the 50 % and 81 % cold-rolled
specimens were much higher than that in the 0 %cold-rolled specimen.

This results strongly suggestthat transformation-induced plasticity happened bydeformation-induced martensitic transformation is oneof the main reason for the high strength and large
ductility of the cold-rolled Fe-24Ni-6Al-0.4C alloy.

Figure 2 In-situ neutron diffraction profiles
during tensile deformation of the 0 %cold-rolled Fe-24Ni-6Al-0.4C.

Figure 3 Changes in fraction of martensite with increasing of the tensile strain in theFe-24Ni-6Al-0.4C; (a) 0% cold-rolled specimen, (b) 50 % cold-rolled specimen, (c) 81 % cold-rolled
specimen.

(1-2)
Deformation behavior of the dual phase (DP) steel
consisting of ferrite phase and martensite phase wasanalyzed by in-situ neutron diffraction during tensile
deformation.

As shown in the schematic illustration ofFigure 1, a tensile test specimen was mounted at thestandard tensile testing system at BL19 TAKUMI as thatthe tensile axis to be aligned 45° with respect to theincident beam.
Figure 4 shows changes in phase stresses (elasticstresses) of ferrite phase and martensite phase derived
from lattice strains of (011) plane perpendicular to thetensile axis.

It is found that large phase stress waspartitioned in martensite phase and that the differenceof phase stress between martensite phase and ferrite

Figure 4 Changes in phase stresses(elastic stresses) of ferrite phase andmartensite
phaseduringtensile
deformation in the DP steel obtained byneutron diffraction analysis.

phase increased with increasing of the applied stress.
Otherthanthepresent

neutrondiffraction

experiment, we have evaluated local strain distribution
during tensile deformation in the DP steel by digital
image correlation (DIC) analysis.

Figure 5 showschanges in average plastic strains of ferrite phase andmartensite phase during deformation.

By combining

the plastic strain distribution obtained by DIC analysis
and the phase stress estimated by the present neutron
diffraction experiment, we successfully reconstructed
stress-strain curves of ferrite phase and martensite
phase in the DP steel separately (Figure 6).

There areFigure 5 Changes in average plasticstrains of ferrite phase and martensite
phase during tensile deformation in the DP
steel obtained by DIC analysis.

several models for predicting macroscopic stress-strain
curve of the multi-phase materials by using stress-strain
curves of each constituent phases.

Within ourknowledge, however, our result shown in Figure 6 is thefirst case that the stress-strain curves of ferrite phaseand martensite phase in the DP steel was obtained
separatelyfrom

theexperimentallyobtained

macroscopic stress-strain curve.
(1-3)
Deformation behavior of dual phase Cu-Zn alloy
during tensile deformation was also investigated byin-situ neutron diffraction.

We confirmed that phasetransformation occurred during deformation.

Figure 6 Stress-strain curves of ferrite
phase (F) and martensite phase (M) in theDP steel reconstructed by combination of
in-situ neutron diffraction analysis and DICanalysis.

(2) 5/16, 17, 19, 20, 2016
(2-1)
Dynamic ferrite transformation is a ferrite transformation occurring during deformation of austenite.
Nowadays, thermomechanical controlling process utilizing dynamic ferrite transformation has been
received much attention because an ultrafine-grained ferrite structure with grain size less than 1 m
can be achieved.

So far, however, many aspects of dynamic ferrite transformation, such asdeformation condition for the occurrence of dynamic ferrite transformation, formation mechanism of theultrafine-grained structure, partitioning behavior of elements, and so on, have not been fully understoodyet.
Inthepresentinvestigatedexperiment,elements

behavior

oftransformation

bywe

partitioning

dynamicferrite

in-situneutrondiffraction analysis during compression
at elevated temperature using a newly
developed

thermomechanicalprocessing simulator installed at BL 19TAKUMI.

Figure 7 represents anappearance of the thermomechanicalprocessing simulator and a schematicillustration for an alignment of aspecimen with respect to the incident
and diffracted neutron beams.

Figure 7(a) The thermomechanical processing simulator
installed at the BL 19 TAKUMI, and schematic illustration of
the testing part of the simulator, (b) The geometry of thecompression experiment with respect to the incident anddiffracted neutron beams.

Thespecimen was austenitized at 1000 °C
for300s,andcooledtothedeformation temperature ranging from
650–750°C.

Then,

uniaxial

compressive deformation by at most 60 % was appliedat the temperature.

Strain rate for the compressive

deformation was 1 × 10-3 s-1.

The specimen wasplaced between two anvils (c-BN) in the chamber, andheated by induction heating system.

The chamber

moves upward by the half of deformation amount sothat neutron beam is always irradiated at the center ofthe specimen during compression experiment.
Figure 8 shows changes in lattice constants ofstaticallytransformed

ferritetransformed ferrite (strain rate:Rietveld analysis.

and10-3

dynamicallys-1)

obtained by

As shown in Figure 8, the lattice

constants of statically transformed ferrite (triangles)
did not change during transformation.

In contrast, theFigure 8 Change in lattice constants ofstatically transformed ferrite (triangles) anddynamically transformed ferrite (circles)
during transformation.

lattice constants of dynamically transformed ferrite (circles) decreased during transformation.

The

same tendency was also confirmed in the previous experiment (2014E0003) with the strain rate of 10-2
s-1. It should be noted that the decrease in lattice constant of dynamically transformed ferrite wasopposite tendency from the elastic strain by compressive deformation.

The results suggest thatpartitioning behavior of elements in dynamic transformation changed with proceeding thetransformation, i.e., para-equilibrium partitioning to ortho-equilibrium partitioning.
(2-2)
It has been reported that medium Mn steels which contain a certain amount of retained austenite
exhibits excellent mechanical properties. In order to improve mechanical properties of medium Mnsteels much more through thermomechanical controlling process, it is necessary to understand theformation mechanism of retained austenite.

In the present experiment, we investigated reverse

transformation behavior of the medium Mn steel by using the newly developed thermomechanicalcontrolling simulator.

We are now analyzing the obtained neutron diffraction profiles.

(2-3)
Titanium and Titanium alloys are widely used in aeroplane and space applications, because of theirlight weight, excellent high-temperature strength and corrosion resistance.

Aeroplane parts ofTitanium alloys are fabricated through hot forging at elevated temperatures after melting and casting.
The hot deformation (forging) is carried out in beta single-phase region as well as in alpha + beta
two-phase region, so that complicated microstructures are maintained to achieve appropriate
properties. However, a number of phenomena happening during such thermomechanical controlling
processes are still unclear.

In the present experiment, we investigated phase transformation behavior

of Ti-6Al-4V alloy during deformation at elevated temperature by using the newly developed
thermomechanical controlling simulator.
profiles.

We are now analyzing the obtained neutron diffraction