Abstracts of ISAFM2017
The 8th International Symposium on Advanced
Functional Materials
between Yokohama National University
and Changwon National University

February 20 - 22, 2017
Yokohama National University
Education and Culture Hall
Yokohama, Japan

Organized by
Yokohama National University, Department of Solid State Materials and Eng., Japan
Changwon National University, Department of Nano and Advanced Materials Eng., Korea

Supported by
Yokohama National University, Japan
Changwon National University, Korea

1List of participants
Title

Name

Japanese reading

Affiliation

faculty

Hiroshi Fukutomi

福富 洋志

YNU, JAPANfaculty

Osamu Umezawa

梅澤 修

YNU, JAPANfaculty

Kohki Mukai

向井 剛輝

YNU, JAPANfaculty

Junichi Tatami

多々見 純一YNU, JAPANfaculty

Shoichi Hirosawa

廣澤 渉一

YNU, JAPANfaculty

Wataru Nakao

中尾 航

YNU, JAPANfaculty

Mahoto Takeda

竹田 真帆人YNU, JAPANfaculty

Makoto Hasegawa

長谷川 誠

YNU, JAPANfaculty

Hiroshi Nakatsugawa

中津川 博

YNU, JAPANfaculty

Tomoyoshi Maeno

前野 智美

YNU, JAPANfaculty

Norimitsu Koga

古賀 紀光

YNU, JAPANfaculty

Hideaki Iwaoka

岩岡 秀明

YNU, JAPANfaculty

Kazuto Okayasu

岡安 和人

YNU, JAPAN

student

Shosuke Kogo

古後 翔佑

YNU, JAPAN

student

Fumimasa Suetsugu

末続 文正

YNU, JAPAN

student

Kotatsu Hirata

平田 弘達

YNU, JAPAN

student

Ayuka Matsugami

松上 歩加

YNU, JAPAN

student

JangWon Lee

ジャンウォン リ

YNU, JAPAN

student

Weibo Li

ウイボ リ

YNU, JAPAN

student

Takayuki Yamashita

山下 享介

YNU, JAPAN

student

Jun Seop Kim

金 俊燮

YNU, JAPAN

student

Natsuko Kimura

木村 奈津子YNU, JAPAN

student

Takahiro Yamazaki

山崎 貴大

YNU, JAPAN

student

Shuntaro Tsukamoto

塚本 俊太郎YNU, JAPAN

student

Yusaku Yasumori

安盛 雄作

YNU, JAPAN

Title

Name

Japanese reading

Affiliation

faculty

Chan Gyu Lee

チャン ギュ イ

CNU, KOREA

faculty

Dong Sik Bae

ドン シク べCNU, KOREA

facultyHyun Uk Hong

ヒョン ウク ホン

CNU, KOREA

faculty

Hee Kyu Choi

ヒ ギュ チェ

CNU, KOREA

faculty

Mathieu Terner

マチュー ターナー

CNU, KOREA

faculty

Sun Woog Kim

ソン ウク キム

Sejong Uni., KOREA

student

Jeong Hun Son

ジョン フン ソン

CNU, KOREA

student

Won Joon Lee

ウォン ジュン イ

CNU, KOREA

student

Hyeon Tae Im

ヒョン テ イム

CNU, KOREA

student

Dong Gyu Lee

ドン ギュ イ

CNU, KOREA

student

Yeon Bin Choi

ヨン ビン チェ

CNU, KOREA

student

Ji Young Ock

ジ ヨン オク

CNU, KOREA

student

Han Ul Choi

ハン ウル チェ

CNU, KOREA

student

Hyun Mi Lee

ヒョン ミ イ

CNU, KOREA

student

Kyeong Yong Shin

ギョン ヨン シン

CNU, KOREA

student

Chi Won Kim

チ ウォン キム

CNU, KOREA

2

ISAFM2017
The 8th International Symposium on Advanced
Functional Materials
between Yokohama National University
and Changwon National University

February 20 - 22, 2017
Yokohama National University
Education and Culture Hall
Yokohama, Japan

Organized by
Yokohama National University, Department of Solid State Materials and Eng., Japan
Changwon National University, Department of Nano and Advanced Materials Eng., Korea

Supported by
Yokohama National University, Japan
Changwon National University, Korea-1-Organizing Committee
General ChairsProf. Shoichi Hirosawa, Yokohama National University, JAPAN, hirosawa-shoichi-mc@ynu.ac.jp
Prof. Mahoto Takeda, Yokohama National University, JAPAN, takeda-mahoto-mk@ynu.ac.jp
Prof. Chan Gyu Lee, Changwon National University, KOREA, chglee@changwon.ac.kr
Prof. Dong Sik Bae, Changwon National University, KOREA, dsbae7@changwon.ac.kr

Academic Committee ChairsProf. Hiroshi Fukutomi, Yokohama National University, JAPAN, fukutomi-hiroshi-pk@ynu.jp
Prof. Osamu Umezawa, Yokohama National University, JAPAN, umezawa-osamu-fv@ynu.ac.jp
Prof. Kohki Mukai, Yokohama National University, JAPAN, mukai-kohki-cv@ynu.ac.jp
Prof. Junichi Tatami, Yokohama National University, JAPAN, tatami-junichi-xv@ynu.ac.jp
Prof. Wataru Nakao, Yokohama National University, JAPAN, nakao-wataru-hy@ynu.ac.jp
Prof. Hiroshi Nakatsugawa, Yokohama National University, JAPAN, nakatsugawa-hiroshi-dx@ynu.ac.jp
Prof. Makoto Hasegawa, Yokohama National University, JAPAN, hasegawa-makoto-zy@ynu.ac.jp
Prof. Tomoyoshi Maeno, Yokohama National University, JAPAN, maeno-tomoyoshi-yf@ynu.ac.jp
Prof. Norimitsu Koga, Yokohama National University, JAPAN, koga-norimitsu-sx@ynu.ac.jp
Prof. Hideaki Iwaoka, Yokohama National University, JAPAN, iwaoka-hideaki-xd@ynu.ac.jp
Mr. Kazuto Okayasu, Yokohama National University, JAPAN, okayasu-kazuto-kx@ynu.ac.jp
Prof. Hyun Uk Hong, Changwon National University, KOREA, huhong@changwon.ac.kr
Prof. Hee Kyu Choi, Changwon National University, KOREA, hkchoi99@changwon.ac.kr
Prof. Mathieu Terner, Changwon National University, KOREA, mathieu@changwon.ac.kr
Prof. Sun Woog Kim, Sejong University, KOREA, skim80@sejong.ac.kr-2-

Preface
Materials science and engineering is constructed by interdisciplinary fields, andencompasses complete knowledge for materials bridging the basic and appliedsciences. The International Symposium on Advanced Functional Materials,
ISAFM, was launched in 2009 at Changwon, Korea, to offer a valuable
opportunity for exchanging knowledge and scientific idea of researchers andstudents at both of Yokohama National University (YNU) and Changwon
National University (CNU). The ISAFM 2017 held in 20-22 February, 2017 at
Yokohama, Japan, is the 8th YNU/CNU symposium, and 16 papers concerning
metallic materials, energy conversion materials, nano-materials and nanotechnology are included together with four plenary lectures as invited
presentations. The symposium also aims to make friendship among participants,
and to encourage international collaboration and exchange program between
both national universities.
I would like to express sincere thanks and gratitude to my colleagues who
prepared all the ISFAM events, in particular, Prof. M. Takeda. I wish allparticipants to have a pleasant stay in Yokohama, and I hope that the ISAFM
2017 will remain in their memory as an enjoyable and scientifically important
experience.
21 February, 2017

Shoichi HIROSAWA
Yokohama National University-3-General Information
Welcome reception

Welcome reception will be held on February 20 in the Cafeteria Ⅱ COOP, 18:00-19:30.

Registration fee
・ Registration desk will operate at 8:45-9:15 February 21 in the Education and Culture Hall.

Japanese faculty: 33,000JPY
Japanese student: 22,000JPY
Korean faculty: 10,000JPY (On site by cash)
Korean student: 10,000JPY (On site by cash)

Lunch


Lunch will be held on February 21 in CafeteriaⅠ(Renga Kan), 12:00-13:15

BanquetBanquet will be held on February 21
in CRUISE-CRUISE YOKOHAMA (Sky Building 27F),
Camelot Japan(Accommodation)

19:00-21:30

Accommodation
Yokohama
StationHotel Yokohama Camelot JapanSky Building

Language(Banquet)

ENGLISH will be the official language during ISAFM2017.

-4-

Campus Map of Yokohama National University

Bus Stop:
Kokudai-nishi

Cafeteria Ⅱ COOP
(Welcome reception)

Bus Stop:
Daigakukaikan-mae

Cafeteria Ⅰ Renga Kan(Lunch)Education and Culture Hall
(Registration and Symposium)-5-By Airplane
Narita Airport Narita Express (90 min.) Yokohama Station
Narita Airport
Airport Limousine Bus (120 min.)
YCAT*
Haneda Airport
Keihinkyuko Line (20 min.) Yokohama Station
Haneda Airport Keikyu Bus (30 min.) YCAT*YCAT(Yokohama City Air Terminal) is located in the SKY Building behind the east exit of
Yokohama Station.

By Bullet Train
If you get off at Tokyo Station Take any of the JR lines (The ride time Tokaido Line: 30 min.,Yokosuka Line: 35 min., Keihin Tohoku Line: 45 min.)Get off at Yokohama Station
If you get off at Shin-Yokohama Station Take the Yokohama City Subway (About a 10 min.
ride) Get off at Mitsuzawa-kamicho Station

By Train
The Nearest Station: [Yokohama Municipal Subway] Mitsuzawa-kamicho Station
walk

By Taxi
It takes 15 minutes from the West Exit of Yokohama Station.

-6-

About a 16 min.

By Bus
It takes 15-20 minutes from the bus terminal at the West Exit of Yokohama Station to YNU.

Bus Stop at the West Exit of Yokohama Station

9-7-

Program
Monday, February 20, 2017
■ Welcome reception, 18:00-19:30
・ Cafeteria Ⅱ COOP

Tuesday, February 21, 2017
■ Registration, 8:45-9:15
・ Education and Culture Hall

■ Opening Address, 9:15-9:25
・ 9:15-9:18 President of YNU: Prof. Yuichi Hasebe (planned) (YNU, JAPAN)
・ 9:18-9:21 Prof. Chan Gyu Lee (CNU, KOREA)
・ 9:21-9:25 Prof. Shoichi Hirosawa (YNU, JAPAN)■ Oral Session 1：Chairman, Prof. Wataru Nakao (YNU, JAPAN)
9:25-10:35 (Lecture; 10min and Plenary lecture; 20min)
・ 9:25-9:50 Plenary lecture01: Prof. Sun Woog Kim (Sejong University, KOREA)
 Design of Novel Oxide Phosphor Exhibiting Long Wavelength Emission
・ 9:50-10:05 lecture001 : Won Joon Lee (CNU, KOREA)
 Fabrication and Characterization of Gd doped CeO2 by Solvothermal process
・ 10:05-10:20 lecture002: Ayuka Matsugami (YNU, JAPAN)
 Low wear rate of AlN ceramics based on tribo-chemical reactions
・ 10:20-10:35 lecture003: Ji Young Ock (CNU, KOREA)
 A simple way to synthesize K3V5O14 red inorganic pigment by a WASSR method-8-

■ Oral Session 2：Chairman, Prof. Hee Kyu Choi (CNU, KOREA)
10:50-12:00 (Lecture; 10min and Plenary lecture; 20min)
・ 10:50-11:15 Plenary lecture02: Prof. Tomoyoshi Maeno (YNU, JAPAN)
 Improvement of uniformity in hardness distribution of die-quenched products in hot
stamping using rapid resistance heating
・ 11:15-11:30 lecture004: Kyeong Yong Shin (CNU, KOREA)
 Effect of Heat Treatment on Microstructure Evolution and the Tensile Properties of Haynes
282 Superalloy
・ 11:30-11:45 lecture005: Weibo Li (YNU, JAPAN)
 A Review of subsurface crack initiation models in high-cycle fatigue for titanium alloys
・ 11:45-12:00 lecture006: Hyeon Tae Im (CNU, KOREA)
 Fabrication and Characterization of Ag-SiO2 / Inorganic Antimicrobial coating agent■ Lunch, 12:00-13:15
・ CafeteriaⅠ(Renga Kan)

■ Oral Session 3：Chairman, Prof. Makoto Hasegawa (YNU, JAPAN)
13:15-14:25 (Lecture; 10min and Plenary lecture; 20min)
・ 13:15-13:40 Plenary lecture03: Prof. Mathieu Terner (CNU, KOREA)
 The prospect of Metal Additive Manufacturing towards performance and innovations
・ 13:40-13:55 lecture007: Takayuki Yamashita (YNU, JAPAN)
 The stability of retained austenite and transformation behaviour in TRIP steels at low
temperature
・ 13:55-14:10 lecture008: Chi Won Kim (CNU, KOREA)
 Atom probe study of the precipitation of κ-carbide with Si addition and dislocation behavior
in a cast FeMnAlC lightweight steel
・ 14:10-14:25 lecture009: Shosuke Kogo (YNU, JAPAN)
 Thermodynamic Assessment and Determination of Phase Diagram Including Spinodal Lines
in Al-Mg Alloy-9-■ Oral Session 4：Chairman, Prof. Hyun Uk Hong (CNU, KOREA)
14:40-15:50 (Lecture; 10min and Plenary lecture; 20min)
・ 14:40-15:05 Plenary lecture04: Prof. Norimitsu Koga (YNU, JAPAN)
 Analysis of Strain distribution in deformed materials by digital image correlation
・ 15:05-15:20 lecture010: Dong Gyu Lee (CNU, KOREA)
 Morphology of Aluminium (Al 3003) Chemical Etching for Insert Molding
・ 15:20-15:35 lecture011: Kotatsu Hirata (YNU, JAPAN)
 Microstructural Change of Thermal Barrier Coatings Deposited on TiAl Alloy・ 15:35-15:50 lecture012: Yeon Bin Choi (CNU, KOREA)
 Synthesis and Characterization of K2Ti6O13 Whisker by Flux method■ Oral Session 5：Chairman, Prof. Dong Sik Bae (CNU, KOREA)
16:05-17:05 (Lecture; 10min and Plenary lecture; 20min)
・ 16:05-16:20 lecture013: Han Ul Choi (CNU, KOREA)
 Effect of Preparation Methods on the Electrochemical Performance of All-solid-state Li-S
battery
・ 16:20-16:35 lecture014: Fumimasa Suetsugu (YNU, JAPAN)
 Control of Electron Coupled State in Superlattice of PbS Quantum Dots by Replacing
Ligands
・ 16:35-16:50 lecture015: Hyun Mi Lee (CNU, KOREA)
 The effect of hydrogen sulfide(H2S) on sulfur poisoning of nickel-yttria stabilized
zirconia(Ni-YSZ) anode supported solid oxide fuel cells
・ 16:50-17:05 lecture016: Jang Won Lee (YNU, JAPAN)
 Competition Behavior between defect propagation and self-healing under high temperature
creep in Fiber-reinforced self-healing ceramics■ Closing remark, 17:05-17:15
・ Prof. Hiroshi Fukutomi (YNU, JAPAN)- 10 -

■ Banquet, 19:00-21:30
・ CRUISE-CRUISE YOKOHAMA (Sky building 27F)

Wednesday, February 22, 2017
■ Lab Tour, 9:00-10:30■ Departure- 11 -

Abstracts- 12 -

Plenary lecture 01

Design of Novel Oxide Phosphor Exhibiting Long Wavelength Emission
Sun Woog Kim1†, Takuya Hasegawa2, Kenji Toda3, Mineo Sato3
Sejong University1, Kochi University2, Niigata University3
209 Neungdong-ro, Gwangjin-gu, Seoul 05006, Republic of Korea1, 200 Otsu, Monobe, Nankoku
City, Koch 783-8502, Japan2, 8050 Ikarashi 2-nocho, Niigata 950-2181, Japan3
TEL: +81-2-6935-2444 E-mail:skim80@sejong.ac.kr

Typical white LEDs composed of blue light excitable green- and red-emission phosphors andblue LED chip. As a red-emission phosphor, Eu2+-activated nitrides or Mn4+-doped fluoride
phosphors have been mainly used, however, these phosphors require special furnace or atmosphereto synthesize a single phase materials. The development of novel red-emission phosphors, which
can be easily synthesized in normal processing, is extremely important in white LEDs application.
In addition, blue light excitable long wavelength emission phosphors have been recently
investigated as a spectral converter to enhance the energy conversion efficiency of silicon solar cells.
Therefore, the investigations have been devoted to search for novel approach to develop novel longwavelength emission phosphor for use in white LEDs and silicon solar cells as a spectral converter.
In this study, we proposed the further approach to develop novel long wavelength emission
phosphors and presented the luminescence properties of the novel phosphors developed using
further approach.

- 13 -

Lecture 001
Fabrication and Characterization of Gd doped CeO2 by Solvothermal process
Won-Joon Lee, Jeong-Hun Son, Dong-Sik Bae†
Department of Advanced Materials Engineering, Changwon National University
Department of Convergence Materials Science and Engineering, Changwon National Univ., 20
Changwondaehak-ro Uichang-gu Changwon-si, Gyeongsangnam-do 641-773 KOREA.
TEL: +82-55-275-5475
E-mail: dsbae7@changwon.ac.kr
Abstract Gd doped CeO2 nanopowders were prepared under low temperature and high pressure
conditions by solvothermal process from metal nitrates with aqueous ammonium hydroxide. Gd
doped Ceria nanopowders were obtained by a reaction at the temperature range of 120℃~180℃
for 2~6h. The average size and size distribution of the synthesized particles were around 5~10nm
and spherical, respec1tively. The specific surface area of the synthesized Gd doped CeO2 particles
above 130m2/g. The XRD diffraction pattern shows that the synthesized powders were crystalline.
This study has shown that the synthesis of Gd doped CeO2 nanopowders is possible undersolvothermal conditions in distilled water/ethanol solution. The effects of synthesis parameters,such as the solvent ratio of starting solution, pH of starting solution, reaction temperature and time,
are discussed.
Experimental Cerium acetate and Gadolinium nitrate hexahydrate (3mol %) are mixed in distilledwater and ethanol. Using ammonium hydroxide to a pH in the range 7~11. The precipitate waswashed with distilled water and then Solvothermal process for 2~6h at 120~180℃ to convert to Gd
doped CeO2. After performing Solvothermal process, washing 5 times for 10 min with ethanol anddried at 100℃ for 24h in air.
Results and Discussion The crystal shape and size of synthesized Gd doped ceria were
controlled through reaction temperature and ratio of ethanol and water. The synthesized Gd doped
ceria nanopowders was crystallinity and sure to include crystal structure of ceria on Gd as matrix at
X-ray Diffraction analysis. The particle size was calculated using a Scherer equation and it was
3~6nm. The shapes of synthesized Gd doped ceria were spherical at Field Emission ScanningElectron Microscopy. The specific surface area of Gd doped ceria were characterized by BET thataround 110~130m2/g.

Fig.1 XRD diffraction patterns of Gd doped
CeO2.

Fig.2 FESEM image of Gd doped CeO2.

References
1) T. S. Zhang, J. Ma, L. B. Kong, P. Hing and J. A. Kilner, “Preparation and mechanical propertiesof dense Ce0.8Gd0.2O2-δ ceramics”, Solid State Ionics. 167 (2004) 191.
2) G Dell'Agli, L Spiridigliozzi, A Marocco, G. Accardo, C. Ferone and R. Cioffi, “Effect of themineralizer solution in the hydrothermal synthesis of gadolinium-doped (10% mol Gd) ceria
nanopowders.”, J Appl Biomater Funct Mater. 14(2) (2016) e189.
- 14 -

Lecture 002
Low wear rate of AlN ceramics based on tribo-chemical reactions
Ayuka Matsugami1, Junichi Tatami1, Motoyuki Iijima1, Hideyuki Ohguni2
1

Yokohama National University, 2Sumitomo Electric Industries, Ltd.
1
Yokohama, Kanagawa 240-8501, Japan, 2Itami,Hyogo 664-0016, Japan
TEL: +81-45-339-3959
E-mail: tatami-junichi-xv@ynu.ac.jp
Abstract Wear behavior of material depends on the properties of the material. According to thewear map by Adachi (1995)1), it suggests that a threshold of the mild wear region and the severe
wear region be lower if soft compounds are on worn surface. Moreover, the tribo-chemical reaction
could be incited on the surface of materials by friction or wear depending on surrounding
atmosphere. For example, it is said that aluminum nitride, AlN, forms oxide and hydroxide layer
during ball milling. It should be easy to be incited tribo-chemical reaction. Therefore, in this study,
we aim to achieve low wear rate of AlN ceramics based on tribo-chemical reactions.
Experimental AlN ceramics were fabricated using the AlN powder with 0.6 mol% of the Y2O3 powder. The
green bodies of the powder mixture were fired at 1850℃ for 2 h in 0.6 MPa N2. After polishing the surfaceof the AlN ceramics, ball-on-disk test of the specimens was performed under 20% relative humidity (lowhumidity air), over 50% relative humidity (high humidity air) and in CO2 flow under 20% relative humidity(CO2 flow air). After the wear test, their cross section profiles were estimated by lasermicroscope to calculate
their wear volume and their worn surfaces were observed by SEM and EDS.
Results and Discussion Fig.1 shows wear volume of AlN ceramics under different atmosphere andspecific wear rate. We discover that the wear behavior of AlN ceramics strongly depends on thehumidity. From the observation of the worn surfaces by SEM, we found the differences depending on theatmosphere. After the test in the low humidity air, AlN grains fell off because the intergranularfracture is dominant. (Fig.2(a))On the other hand, after the test in the high humidity air, the worn
surface is very smooth because tribo-chemical reactions are dominant. (Fig.2(b)) To promote thereactions, the other ball on disk test was performed in CO2 flow air. In this case, the lowest wear
rate of 2.6×10-10 mm2/N was achieved. The low wear rate resulted from the soft layer formed bytribo-chemical reactions on the worn surface, which prevents from thermal shock.(Fig.3)

Fig.2 SEM images of worn surfaces of AlN ceramics afterball-on-disk test in (a) low humidity air and (b)high humidity
air.

Fig.1 Wear volume of AlN ceramics under
different atmosphere and specific wear rate
Fig.3 SEM image and EDS image of worn surface of AlN
ceramics after ball-on-disk test in CO2 flow air.

Reference
1) K. Adachi, et al., Wear Map of Ceramics, Wear, 209-204, 291-301 (1997)- 15 -

Lecture 003

A simple way to synthesize K3V5O14 red inorganic pigment by a WASSR method
Ji-Young Ock1, Sun-Woog Kim2† and Dong-Sik Bae1†
Changwon National University1, Sejong University2
20, Changwondaehak-ro, Uichang-gu, Changwon-si, Gyeongsangnam-do, Republic of Korea1, 209,
Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea2
TEL: +81-55-275-5475

E-mail:dsbae7@changwon.ac.kr1, E-mail:skim80@sejong.ac.kr2

Abstract K3V5O14 inorganic red pigment was synthesized by a water assisted solid state reaction(WASSR) method, which is simple low temperature synthesis method. The K3V5O14 pigment
showed a strong broad optical absorption in the green light region owing to the charge transfer (CT)transition from the O2- 2p orbital to V5+ 3d orbital in the VOn (n = 4 and 5) polyhedral. At an
excitation wavelength of 365 nm, this pigment exhibited a broad red emission with a peak at 613.2
nm. The K3V5O14 pigment showed a bright-vivid red body color and the L*, a* and b* values were52.1, 35.75 and 19.06, respectively.
Experimental K2CO3 and V2O5 was mixed for 1 min using a agate mortar, and then the mixture wasplaced into a teflon bottle and stored at 100 ºC for 24 h in oven. The obtained sample was heated at
400 ºC for 6 h to obtain a single phase with high crystallinity.
Results and Discussion Upon the monitoring wavelength at 365 nm, K3V5O14 pigment showed
an asymmetric broad emission band due to 3T2 → 1A1 and 3T1 → 1A1 transition of the [VO4]3- group(Fig. 1). From the UV-vis diffuse reflectance spectrum (Fig. 2), K3V5O14 pigment have a strong
broad optical absorption from 250 to 560 nm, which is attributed to the energy transfer from O2- 2p
orbital to V5+ 3d orbital in the VOn (n = 4 and 5) polyhedral. It is clear that an optical absorption
form 400 to 550 nm is due to the VO5 polyhedron. The pigment showed a higher reflection at the
wavelength from 560 nm, which is good matched to the emission band of the K3V5O14 pigment. As
a result, The K3V5O14 pigment showed a bright-vivid red body color and the L*, a* and b* values
were 52.1, 35.75 and 19.06, respectively.

Fig 1. Excitation and emission spectra ofK3V5O14 sample after annealing treatment at
400ºC.

Fig 2. UV-vis diffuse reflectance spectrum of K3V5O14
pigment after annealing treatment at 400ºC.

- 16 -

Plenary lecture 02
Improvement of uniformity in hardness distribution of die-quenched products in hot
stamping using rapid resistance heating
Tomoyoshi Maeno*1, Ken-ichiro Mori, Masato Sakagami2, Yoshitaka Nakao2
1

Division of Materials Science and Chemical Engineering, Faculty of Engineering, Yokohama
National University
2

Department of Mechanical Engineering, Toyohashi University of Technology
Yokohama, Kanagawa 240-8501, Japan, Toyohashi, Aichi 441-8580, Japan
TEL: +81-45-3393447
E-mail: maeno-tomoyoshi-yf@ynu.ac.jp

Abstract To improve the uniformity in hardness distribution of die-quenched products, thehardening behaviour of a quenchable steel sheet for hot stamping using rapid resistance heating was
examined in a hot bending experiment. The sheet was heated to 900 °C in several seconds. The
effect of the heat treatment before hot stamping on quenchability in die quenching was examined.
The quenchability was improved by normalising heat treatment because the grain size reduced.
Standard deviation of the hardness in the sheet heated to 900 °C in 3.2 s without holding at theaustenitising temperature was 3%, whereas the deviation reduced to 1% for holding at theaustenitising temperature of 3 s.
Experimental To investigate the hardening behaviour in hot stamping using resistance heating, a
hot hat-shaped bending process using resistance heating was performed. The equipment forresistance heating and the bending dies were installed in a 1500 kN CNC servo press. A typicalquenchable steel sheet 22MnB5 without coating was used for the experiment. The heating
temperature was 900 °C. The heating rate v and holding time at austenitising temperature t werechanged. The blank was heated by passage of direct current for several seconds. The heated blank
was released from the holder immediately after heating, and was transferred to the hat-shaped
bending dies. Furthermore, the effect of grain size of the steel sheet before hot stamping on the
die-quenchability was examined with the normalised and annealed sheets.
Results and Discussion In Fig. 1, as the grain size increases, the hardness decreases. For thelarge grains, the heating time is too short to diffuse carbon in the cementite phase sufficiently.
Hardening of the hot-stamped pars becomes insufficient because of the insufficient austenitisation.
The effect of holding time at austenitising temperature on the hardness of die-quenched parts isshown in Fig. 2. As the holding time at the austenitising temperature increases, the hardness slightly
increases up to t = 5 s. The standard deviation of the hardness is remarkably reduced by holding at
the austenitising temperature above 1 s.

Fig.1 Effect of grain size of steel sheet before
hot stamping on Vickers hardness after die
quenching in hot stamping using resistanceheating for v = 275 °C/s and t = 0 s.

Fig.2 Effect of holding at austenitising temperature
on Vickers hardness and standard deviation for v =275 °C/s.

- 17 -

Lecture 004
Effect of Heat Treatment on Microstructure Evolution and the Tensile Properties ofHaynes 282 Superalloy
Kyeong-Yong Shin1, Byeong-Ook Kong2, Sung-Tae Kang2 and Hyun-Uk Hong1*
Changwon National University1, Doosan Heavy Industries & Construction2
120 Chanwondaehak-ro,Changwon, Gyeongnam 51140, Republic of Korea
222 Doosan volvo-ro, Changwon, Gyeongnam 51711, Republic of Korea

TEL: +82-55-213-3699

E-mail: *huhong@changwon.ac.kr

Abstract In the present study, the effects of three different cooling rates and different aging
treatments were studied to identify their influences on γ' formation and microstructure evolution in
Haynes 282. The high temperature properties, deformation behavior and fracture characteristics
were investigated at 750˚C. The results showed the yield strength of 1step aging following watercooling was higher than 2step aging heat treatment. An attempt has therefore been made to correlate
the tensile properties and dislocations’ characteristics with the observed deformation mechanisms
under different heat treatment conditions. As a result, the dislocation behavior is changed fromstacking fault shearing mechanism to Orowan bypass mechanism while coarsening the γ'.
Experimental The Haynes282 alloy has chemical composition of 20Cr-10Co-8.5Mo-2.1Ti-1.5Al1.5Fe-0.3Mn-0.2Si-0.06C-0.005B and Ni as the balance. The samples of this alloy were conducted
into different three cooling rate after solution treated at 1135˚C for 20min. Also, Different aging
heat treatment was carried out as not only one step aging heat treatment, which is heated at 800˚C
for 4hr, but also two step aging heat treatment, which is heated at 1010˚C for 1hr following 788˚C
for 8hr. The tensile test was proceeded at 750˚C. The samples for initial and deformed
microstructure observation were analyzed by scanning electron microscope (SEM) and transmission
electron microscope (TEM).
Results and Discussion The tensile test is conducted at 750˚C. As a result, Only, The yieldstrength of 1step aging heat treatment following water cooling is higher than 2step aging heat
treatment. The dislocation is different deformation mechanism not only shearing but also bypassing.
In 1step aging heat treatment after water cooling, the dislocation is appeared as stacking fault
shearing by cutting the γ'. On the other hands, others is formed as Orowan looping by bypassing theγ'.

Fig.1 Tensile curves of Haynes 282 at 750ºC
for the various heat treatment

Fig.2 TEM Bright field images showing thedislocation behavior after tensile test at 750ºC : (a)2step aging heat treatment following water cooling,
1step aging heat treatment following (b) watercooling, (c) air cooling and (d) furnace cooling.

References
1) Y. Yuan et al., Scripta Materialia 67, 137-140, 2012
2) F. Sun et al., Journal of Alloys and Compunds 687, 389-401, 20163) J.N. Wagner et al., Materials Science & Engineering A 662, 303-307, 2016
- 18 -

Lecture 005
A Review of subsurface crack initiation models in high-cycle fatigue for titanium
alloysWeibo Li 1, Osamu Umezawa2
1. Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya,
Yokohama, 240-8501, Japan
2. Faculty of Engineering, Yokohama National University79-5 Tokiwadai, Hodogaya, Yokohama,240-8501, Japan
TEL: +81-45-339-3873
E-mail: li-weibo-wv@ynu.jp
Fatigue crack initiation is generally understood to occur on a specimen surface due to irreversible
process of extrusion and intrusion through slip deformation. The subsurface fatigue crack
generation in titanium alloys, however, has been commonly reported in high-cycle regime and at
low temperature.[1-3] The alloy composition, microstructure and loading condition markedly affectcrack generation, and the initiation sites are not associated with pre-existing defects. The subsurface
crack initiation sites appear crystallographic facet or facets in both near α and α-β types titanium
alloys. Based on the linear mechanics evaluation for the subsurface crack propagation, the crack
initiation stage may consume major part of fatigue life.[2,4,5] However, subsurface fatigue crack
initiation does not exhibit direct evidence of cracking and macroscopic support. A number ofstudies have been done to clarify the subsurface fatigue crack generation for titanium alloys andsome models have been proposed how the facet may be formed. Dislocation movement of titanium
alloys was fairly planar and dislocation arrays were piled up in the vicinity of grain boundaries.[2,6]Then the local stress concentration near the grain boundary due to the heterogeneous slip may cause
the subsurface fatigue crack generation and lower the high-cycle fatigue strength. To relax theconcentrated stress, a deformation or microcracking may generate in the adjacent grain. However,no evidences have shown the microcrack initiated at the localized deformation structure directly.
The characterization of subsurface fatigue crack initiate sites of near  and - types titanium
alloys and their cracking models proposed were reviewed to make unknown issues clarified in theprevious works.
The subsurface crack initiation of near  and - types titanium alloys is common in both dwell
fatigue and high-cycle fatigue. The facets formed under different loading conditions seem
qualitatively similar, and most of the facets form on or near the basal plane. The heterogeneous
micro-plasticity deformation due to planar slip and restricted system remarkably cause subsurface
fatigue crack, on which stress redistribution may play an important role. However, it has not beenclear what kinds of stresses on the basal plane provide the facet formation such as tensile stress,
shear stress and their combination.
The crack initiation sites consisted of facets mostly on near basal plane of  grain, although the
crystallographic orientation and surface topography of the facets presented a subtle difference. The
crack initiation mechanisms were a quasi-cleavage accompanying high normal stress on the plane, acombination of basal slip and normal stress across the basal plane, and a pure slip on facet plane
inclined near 45 degree to loading axis.
References[1] O. Umezawa, et al., Advances in Cryo. Eng. Mater., Vol.60 AIP Conf. Proc. 1574 (2014) 34-41.
[2] O. Umezawa and K. Nagai, ISIJ Inter., 37 (1997) 1170-1179.
[3] O. Umezawa, et al., Advances in Cryo. Eng. Mater., Vol.40 (1994) 1231-1238.
[4] M. Hamada and O. Umezawa, ISIJ Inter., 49 (2009) 124-131.
[5] O. Umezawa, M. Hamada and T. Tatsumi, Procedia Materials Science, 12 (2016) 48-53.
[6] H. Yokoyama, et al., Metall. Mater. Trans. A, 31A (2000) 2793-2805.

- 19 -

Lecture 006
Fabrication and Characterization of Ag-SiO2 / Inorganic Antimicrobial coating agent
Hyeon-Tae Im, Dong-Sik Bae†
Department of Advanced Materials Engineering, Changwon National University
20 Changwondaehak-ro Uichang-gu Changwon-si, Gyeongsangnam-do 641-773 KOREA
TEL: +81-55-275-5475 E-mail: dsbae7@changwon.ac.kr
Abstract In recent years, attention has been increasingly focused on the problem of theenvironment by all over the world and the desire to enjoy a pleasant life has been reflected in theconcept of 'environmentally friendly' living environment. This study is concerned with thedevelopment of antimicrobial coatings for preventing contamination and increasing antimicrobialactivity. Antimicrobial coating agents are compounds that inhibit or kill microorganisms.
Antimicrobial coatings are applied to the surface of daily necessities, medical devices, industrial
products, electrical appliances, fabrics, and interior building materials, etc.
Experimental In this experiment, the Ag-SiO2 particles was prepared by sol-gel method. The
inorganic hybrid binder was manufactured by sol-gel method. It was prepared by a silica compoundsuch as silica-sol and TEOS. Synthesized coating sample was manufactured using coating solutionthat was proceeded by ball-milling method for 6hr by the addition of Ag-SiO2 nanoparticles. The
microstructure and composition of the coating layer measured by SEM and EDS. The physicalproperties were characterized by pencil hardness, level of adhesion and salt spray. Disk diffusion
test was easy and objective testing method on the antibacterial activity of antibacterial agent itself.
Results and Discussion In this study, the Ag-SiO2 / inorganic antimicrobial coating agent wasformed to 10μm ~ 25μm coating thickness and microstructure that judged the Ag-SiO2 particles
were uniformly well distributed on coating layer. The results of adhesive and hardness
measurements were investigated having adhesive property was excellent as 5B. The hardness was
as 8H. The higher the Ag-SiO2 particles, the better the stain resistance and the antimicrobial activity.

Fig.1 Disk diffusion test of synthesized by
Ag-SiO2 nanoparticles and inorganic binder;(A)5g, (B)0g and (C)2g

Fig.2 FE-SEM image of synthesized by Ag-SiO2
nanoparticles and inorganic binder.

References
1) Kugel AJ et al., Combinatorial materials research applied to the development of new surface
coatings XII: novel, environmentally friendly antimicrobial coatings derived frombiocide-functional acrylic polyols and isocyanates. J. Coat. Technol. Res., 6, 107 (2009)
2) Limei Chen et al., Chemical assembly of silver nanoparticles on stainless steel for antimicrobial
applications, Surface & Coatings Technology, 204, 3871 (2010)
3) Klasimir Vasilev et al., Antibacterial Surfaces for biomedical devices, Expert Rvi. Med. Devices., 6, 553 (2009)- 20 -

Plenary lecture 03
The prospect of Metal Additive Manufacturing towards performance and innovations
Mathieu Terner1,2, Sara Biamino2, Jeong-Seok Lee1
1

1

Changwon National University, 2Politecnico di Torino

20 Changwondaehak-ro, 51140 Changwon-si, Republic of Korea,
2
Corso Duca degli Abruzzi 24, 10129 Turin, Italy
TEL: +82-55-213-3698

E-mail: mathieu@changwon.ac.kr

Abstract: Powder-based Metal Additive Manufacturing has emerged for a few years as anencouraging solution for the production of metal parts with outstanding characteristics. Additive
Manufacturing is acknowledged to offer exceptional advantages including complexity for free,near-net-shape production and waste reduction. A unique set of materials properties is also obtained.
The present communication reports encouraging production of Ti-based alloys by means threedifferent Additive Manufacturing processes. First, the production of γ-TiAl alloys by Electron Beam
Melting (EBM) for application in gas turbine engines is described in details. The materials
exhibited excellent specific properties analogous to heavy-weight superalloys. Second, theproduction of the well-known Ti-6Al-4V alloy by Selective Laser Melting (SLM) is reported. The
importance of optimizing the energy density during the process is in particular highlighted. At last,
an innovative production of Ti-6Al-4V by means of Digital Light Processing (DLP) is described.
Initially limited to the production of plastics parts, properly mixing powders with the liquid
photopolymer allows producing a composite which may be ultimately sintered into a porous
metallic part.
Experimental: 3rd-generation γ-TiAl based powders were used as starting materials for the EBM
process, in which the parts are built layer-by-layer by selective fusion of the powder under vacuum
pressure by a high energy electron beam. The numerous process parameters were optimized toreduce residual porosity. Subsequent heat treatments in vacuum were studied to tailor the
microstructure towards optimum mechanical properties for gas turbine engine structural
applications. For the SLM production of Ti-6Al-4V, fine pre-alloyed powders were used as starting
materials. The selective fusion of the powder is realized in controlled atmosphere with a laser beam
as the energy source. The process parameters were controlled and their effect were studied, namely
the laser power, hatch spacing, scanning speed, layer thickness and scanning strategy. The
microstructure and porosity were observed. Finally, recycled unprocessed Ti-6Al-4V powders fromthe previous SLM processing were used for DLP to maintain the costs as low as possible. Here, theprocess is a photopolymerization process, which involves selective solidification of liquid curable
resins by ultraviolet radiation. A high content of powder was mixed with an acrylate-based
photo-curable resin with addition of appropriate additives (i.e. surfactants). The resulting slurry wasthen processed using a custom DLP apparatus.
Results and Discussion: The γ-TiAl alloys produced by the optimized EBM trial
exhibited high homogeneity, very low impurities pick-up, very low residual porosity <<1 % and a fine near-γ microstructure (Fig.1A). Any of the typical microstructures of
γ-TiAl alloys could be set-up by careful heat treatment under vacuum in the vicinity ofthe α-transus temperature. The nearly lamellar microstructure (Fig.1B), consisting in- 21 -

roughly 80 % of lamellar colonies with an average size of about 140 µm pinned at theirboundaries by equiaxed γ-grains smaller than 50 µm, showed in particular excellent
oxidation resistance and encouraging specific strength and creep resistance similar tothat of equivalent Ni-based superalloys used for high temperature structural
applications. At roughly half the density of that of Ni-based superalloys, this makes
γ-TiAl alloys great candidates for rotating high-temperature structural components ingas turbine engines. The Ti-6Al-4V alloys produced by SLM exhibited mechanicalproperties significantly lower than conventional Ti-6Al-4V. Observation of the
microstructure confirmed that the very quick solidification caused by the process leadto the formation of the martensitic α’ microstructure, in place of the desirable α+β. In
addition, the level of residual porosity was rather high. This suggests that the SLM
process may be optimized by varying the energy density value, as well as the
microstructure by proper heat treatment. Finally, an appropriate composition for a
metal-powder rich photo-curable slurry was found with addition of a dispersant and ananti-settling agent in solution. Despite clear difficulties to cure the slurry caused partly
by the low concentration of photosensitive compound, a composite layer was
successfully produced (Fig.2). However, much work has to be conducted to optimize thecomposition of the slurry in order to allow fast curing and multi-layer processing. This
challenging innovative manufacturing method yet offers encouraging considerations.

Fig.1: Microstructure of Ti-45Al-2Cr-8Nb A: as-EBM and B:

Fig.2: One-layer Ti64-photopolymer composite

Nearly-Lamellar after heat treatment

produced by Digital Light processing- 22 -

Lecture 007
The stability of retained austenite and transformation behaviour in TRIP steels at low
temperature
Takayuki Yamashita1, Norimitsu Koga2, Osamu Umezawa2
1. Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya,
Yokohama, 240-8501, Japan
2. Faculty of Engineering, Yokohama National University79-5 Tokiwadai, Hodogaya, Yokohama,240-8501, Japan
TEL: +81-45-339-3873
E-mail: yamashita-takayuki-yz@ynu.jp
Introduction
Low alloy multiphase steels associated with transformation-induced plasticity (TRIP) of retained
austenite (γR) shows a good balance of tensile strength and ductility, since the TRIP causes tomaintain higher work-hardening rate in the high strain regime.[1] Then the stability of γR is a key
factor to control the TRIP effect.[2],[3] Although the stability of γR depends on various factors suchas chemical compositions, morphology and size of austenite, the transformation behaviour ofindividual γR has not been clear. In the present study, the influence of stability of γR on
work-hardening and transformation behavior at low temperature has been investigated for TRIP
steels with different chemical compositions.
Experimental
Two types of low alloy TRIP steel sheets with different volume fraction of γR (low-γ: 9.4% andHigh-γ: 17.2%) containing about 1.3 mass% C were used. The steels were cold-rolled and annealed
at 1063 K in α+γ region, and then cooled to 673 K for austempering. Tensile tests were carried out
at 77 K, 193 K, 233 K and 293 K. The microstructure and crystal orientation of TRIP steels wereanalyzed using electron backscattered diffraction (EBSD). The microstructure consists of ferrite
matrix (αf), bainite (αb) and γR. The γR grains were distributed in αf grains and at the grainboundaries between αf and αb.
Results and Discussion
The steels showed high ductility and tensile strength at 193 K, 233 K and 293 K. The tensile
strength of steels at 77 K was much higher than that of other test temperatures, although the steels
exhibited early fracture. The work-hardening rate was increased with decreasing test temperature.
At 193 K and 233 K, the rate was kept with high value in the high strain regime. The stability of γ R
at 293 K was much higher than that of other test temperatures. The γR at 233 K and 193 K at 10%
strain was mostly transformed. Then the difference of the work-hardening rates among thetemperatures may depend on the stability of γR and the strengthening of αf at lower temperature,
although the influence of TRIP on ductility has not been clear yet.
The most of γR grains after tensile test at 193 K, 233 K and 293 K revealed the orientation near
<111> parallel to the tensile direction, in which their Schmid factors were low as shown in Table 1.
It suggested that the deformability of γR commonly affected to the martensitic (α’) transformation in
the steels at 293 K. The volume fraction of γR at 77 K was less than 1% at 3% strain, the most of γR
were transformed to α’ under stress concentration. The work hardening rate at 193 K, 233 K and 77
K in the steels may depend on their volume fraction of γR.
References[1] M. TAKAHASHI: Nippon Steel Technical Report, 88 (2003), 2[2] K. SUGIMOTO, M. KOBAYASHI, S. HASHIMOTO: Metall. Trans., 23A (1992), 3085
[3] A. ITAMI, M. TAKAHASHI, K. USHIODA: ISIJ int., 35 (1995), 1121
[4] T. YAMASHITA, N. KOGA, O. UMEZAWA: CAMP-ISIJ, 29 (2016), 346- 23 -

Lecture 008
Atom probe study of the precipitation of κ-carbide with Si addition and dislocation
behavior in a cast FeMnAlC lightweight steel
Chi Won Kim1, Jae Hyun Lee1, Jun Oh Moon2, Jae Hoon Jang2, Seong Joon Park2, Bong Ho Lee3,
Young Joo Lee4 and Hyun Uk Hong1*
1

Department of Materials Science and Engineering, Changwon National University, 2Ferrous Alloy
Department, Korea Institute of Materials Science, 3Daegu Gyeongbuk Institute of Science andTechnology, 4Research Institue of Industrial Science and Technology
1

20 Changwondaehak-ro, Uichang-gu, Changwon, Gyeongnam 51140, Republic of Korea
2797 Changwondaero, Sungsan-gu, Changwon, Gyeongnam 51508, Republic of Korea
3
333 Techno-jungangdaero, Dalseong-gun, Daegu 42988, Republic of Korea
4
67 Cheongamro, Nam-gu, Pohang, Gyeongbuk 37673, Rpublic of Korea
TEL: +82-55-213-3699

E-mail: *huhong@changwon.ac.kr

Abstract
In this work, the investigation of precipitation and deformation behavior has been conducted on
the effect of Si addition in a Fe-30Mn-9Al-0.9C cast steel. The result of atomistic analysis reveals
partitioning of alloy elements in Si free and 1% Si added steels(Fig.1). Si atoms are partitioned in
the interface of κ-carbide/γ-matrix and C atoms are excessively partitioned in κ-carbide in a 1% Si
steel (Fig.1b). Si addition affects dislocation behavior to cut through κ-carbides resulting in
Shearband-Induced-Plasticity (SIP) (Fig.2).

Experimental
Hardness was measured for aged Si free and 1% Si steels at 550oC for 100 hours. 3D-APT revealed
compositional distribution on the Si addition. Deformation microstructures were observed by means
of TEM. Also, calculation of the first principle was conducted to elucidate the effect of Si addition on
the evolution of deformation microstructure.

Results and Discussion
Si addition contribute to not only the C-partitioning into κ -carbides but also change of
deformation microstructure. C-enriched κ-carbide in the 1% Si steel effectively retards dislocation
movement due to increased coherency strain and formation of unfavorable Al-C bonding by
shearing κ-carbides. In the first principle calculation, more C atoms are partitioned in κ-carbide
more energies are required to shear κ-carbides.

Fig.1 Compositional distribution observationof Si free and 1% Si added steel by 3D-APT.

Fig.2 Evolution of deformation microstructure of Si
free and 1% Si added steel by TEM.

References
1) C.W. Kim, S.I. Kwon, B.H. Lee, J.O. Moon, S.J. Park, J.H. Lee, H.U. Hong, Atomistic study ofnano-sized κ-carbide formation and its interaction with dislocations in a cast Si added FeMnAlC
lightweight steel, Mater. Sci. Eng. A 673 (2016) 108-113- 24 -

Lecture 009
Thermodynamic Assessment and Determination of Phase Diagram
Including Spinodal Lines in Al-Mg Alloy
Shosuke Kogo1*, Hideaki Iwaoka1, Shoichi Hirosawa1
1

Depart. Mechanical Engineering and Materials Science, Yokohama National University;
79-5 Tokiwadai, Hodogaya-ku, Yokohama-shi 240-8501, JAPAN*Corresponding author. TEL: +81-45-339-3857
E-mail: kogo-shosuke-dg@ynu.jp

Abstract Although several thermodynamic modelling have been carried out for the Al-Mg alloy
system, no previous thermodynamic descriptions could calculate the metastable phase diagram of
L12-type ordered GP zones (Al3Mg). In this study, Calphad-type thermodynamic assessment (Fig.
1) of Al-Mg binary alloys was performed to determine not only the miscibility gap but also thespinodal lines of GP zones. The Gibbs energies of fcc-Al solid solution and ordered GP zones wereexpressed by a four-sublattice model (split compound energy formalism), and a complete
thermodynamic description was obtained from available experimental data. The miscibility gap andspinodal lines calculated from the optimized parameters could satisfactorily reproduce available
experimental data for the equilibrium between fcc solid solution and ordered GP zones (Fig. 2).
Calculation Method GP zone is a coherent precipitate with L12-type ordered structure, and theGibbs energies of both of fcc solid solution and ordered GP zones are needed to calculate themetastable phase diagram. In this study, a thermodynamic model to describe the Gibbs energy of fcc
phase was utilized based on a four-sublattice model (split compound energy formalism). All themodel parameters were finally determined when achieved a best fit to experimental data; e.g.
miscibility gap of GP zones and equilibrium phases, and thermal quantities of mixing enthalpy andactivity. All calculations were performed using Pandat and Thermo-Calc software packages.
Results and Discussion The Gibbs energy curve of fcc phase calculated in this study provides a
miscibility gap type curve. Therefore, a whole metastable phase diagram of GP zones can becalculated by the estimated thermodynamic description. The calculated miscibility gap and spinodal
lines could satisfactorily reproduce experimentally reported reliable data, and thus the equilibrium
between fcc-Al solid solution and ordered GP zones was successfully evaluated for the first time.

SpinodalCriticalanalysis

Optimization• Literature survey(phase-diagram data, thermodynamic data)• Analysis and assembly of information• Modelling selection

Parameter evaluation,
least square fit↓
Comparison between
experimental data andmodel calculations

Nebti
Tarui
Nozato & Ishihara
Rooyen et al.

Osamura & Ogura
Sato et al.
Roth & Raynal
Takahashi & Sato

Miscibility gap• Model-parameter constraints• Re-evaluation of model selection• Weighting of data
• Re-evaluation of data selection

Gault et al.
Takahashi & Sato
Starink & Zahra

Al3Mg

fcc

Optimized
description

Mole fraction of Mg, xMg

Fig.1 Procedure of thermodynamic assessment
utilized in this study.

- 25 -

Fig.2 Calculated miscibility gap (solid lines) andspinodal lines (broken lines) of GP zones(Al3Mg). Experimentally reported data is also
shown by symbols.

Plenary lecture 04
Analysis of Strain distribution in deformed materials by digital image correlation
Norimitsu Koga1, Pham Thi Thanh Huyen2, Osamu Umezawa1
1. Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama,240-8501, Japan
2. Graduate school of Engineering, Yokohama National University79-5 Tokiwadai, Hodogaya,
Yokohama, 240-8501, Japan
TEL: +81-45-339-3873
E-mail:koga-norimitsu @ynu.ac.jp
Introduction
Digital image correlation (DIC) method 1) is adapted to calculating strain from the difference ofimages between before and after deformation. It is applicable to any materials and deformation
modes as long as significant contrasts. We reviewed the principle of DIC method and demonstrated
the strain distribution in tensile deformed ferritic steel.
Experimental
Ultra-low carbon steel (Fe-0.008wt%C) was used for demonstrating strain distribution formed bytensile deformation. The material was cold rolled with 80 % in reduction and annealed at 983 K for
1.8 ks followed by water quenching. The average grain size was 25 μm. Tensile test was carried out
at 293 K and 77 K. Microstructure was observed by scanning electron microscopy (SEM). SEM
images before and after deformation at the same region in etched specimen were taken for DIC
analysis. DIC analysis was carried out with VIC-2D software (Correlated Solutions Ltd).
Results and Discussion
Figure 1 shows strain distribution along tensile direction in tensile deformed specimen at 293 K (a)and 77 K (b). Strain is indicated by color bar, maximum and minimum strain are twice averagestrain and -1 %, respectively. Strain is homogeneously distributed at 293 K (a) while strain
distribution at 77 K (b) is markedly inhomogeneous; high strain region is larger than twice averagestrain and compressive strain is partly observed even though applying only tensile deformation. The
high and low strain regions tend to be continuously distributed along 45 degree from tensile
direction which is maximum shear stress direction. This inhomogeneous strain distribution at 77 K
is caused by restricting the slip system with lowering temperature.

(a)

Ave strain:6.1%

εxx (%)12

εxx (%)
6(b)

Ave strain:2.9%
5

10

4

8

3

6

2

4

1
Tensile direction

εyy

εxx

2
0
-1

50μm

0

-1

Fig.1 Strain distribution along tensile direction in tensile deformed specimen at 293 K (a) and 77 K (b).

References
1) W. H. Peters, Z.-H. He, M. A. Sutton, W. F. Ranson; Experimental Mechanics, 24 (1984)
117-121.
- 26 -

Lecture 010

Morphology of Aluminium (Al 3003) Chemical Etching for Insert Molding
Dong-Gyu Lee, Jeong-Hun Son and Dong-Sik Bae†
Department of Advanced Materials Science and Engineering, Changwon National University
Department of Advanced Materials Science and Engineering, Changwon National University,
Changwon, 641-773, Korea
TEL: +82-55-275-5475
E-mail: dsbae7@changwon.ac.kr
Abstract Aluminium has a low reduction potential, and the structure of aluminium surface changes
through a chemical etching. The surface area of aluminium increased with chemical reaction. The
morphology of etched aluminium surface change according to a kind of etching solution. HCl,
FeCl3 and mixed acid used for etching agent in order to increase aluminium surface area.
Experimental The precleaning removed oxide film of Al 3003 at using PURICLE C-4. Thereafter,
washing with DI water. The etching solution is etched. The etching solution type was HCl(16.5, 25,33%), FeCl3(33, 50, 100%) and HCl+FeCl3(20, 33%). Experimental value changed such as reaction
temperature and time. Physical washing was performed using ultrasonic. Chemical washing was
performed using diluted nitric acid.
Results and Discussion The structure of etched Al 3003 was observed using FE-SEM(fieldemission scanning electron microscope), OM(optical microscope). As a result of observation, it was
confirmed that etch pits were formed from the etched aluminium surface. The change of etch pit
with time and temperature was confirmed. Etch pits were formed on the aluminium surface toincrease the surface area. The change of the bond strength value with the polymer according to thesurface change was confirmed. The surface roughness was checked using a surface roughness tester.
As a result of confirm the bonding strength with the polymer using a tensile strength machine, abonding strength of aluminium and polymer was above 10MPa.

Fig.1 FE-SEM image of Al 3003 with HCl(25%)
at 30℃for 7min

Fig.2 FE-SEM image of Al 3003
HCl+FeCl3(33%) solution at 30℃for 7min

References
1) O. C¸ akır, “Chemical etching of aluminium”, J. Mater. Process. Technol. 199 (2008) 337
2) B. Qian and Z. Shen, “Fabrication of Superhydrophobic Surfaces by Dislocation-Selective
Chemical Etching on Aluminum, Copper, and Zinc Substrates”, Langmuir 21 (2005) 9007
3) V. Martigovitg, M. Zahoran, I. Kogin~ir and J. Trnovec, “Effect of chemical reaction
stoichiometry on the pressure variations in the etching chamber during etching of aluminium”,
Physics Letters A 173 (1993) 462- 27 -

withLecture 011
Microstructural Change of Thermal Barrier Coatings Deposited on TiAl Alloy
Kotatsu Hirata*1 and Makoto Hasegawa2
1

Department of Systems Integration, Specialization in Solid State Materials and Engineering,
Graduate School of Engineering, Yokohama National University, Japan
2

Division of Materials Science and Chemical Engineering, Faculty of Engineering,
Yokohama National University, Japan
*

79-5, Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan
TEL: +81-45-339-3838, E-mail: hirata-kotatsu-yr@ynu.jp

Abstract Thermal barrier coatings (TBCs) have been widely used to protect the gas turbine blades
and vanes from the corrosion, oxidation and high temperature environment. TBCs are composed ofthermal barrier coating (TBC) layer and bond coat (BC) layer; TBC layer and BC layer are formedby heat-resistant ceramics and oxidation-resistant alloy, respectively. This system is usually applied
to the Ni base superalloy. Recently, in order to improve the low oxidation and creep resistance ofTiAl alloy over 1073 K, TBCs are applied to the TiAl alloy substrate. However, change of
microstructure in this systems is still not known. In this study, TBCs deposited on TiAl alloy areheat exposed in different temperature and time to observe the microstructural change of thesystems.
Experimental Ti-46Al-7Nb-0.7Cr-0.2Ni-0.1Si (mol%) alloy are used for a substrate of TBCs.
Co-32Ni-21Cr-8Al-0.5Y (mol%) alloy is deposited on the substrate as BC layer up to 100 μm inthickness by cold spray (CS) process. 4 mol% yittria stabilized zirconia (YSZ) is deposited by air
plasma spray (APS) process up to 250 µm in thickness on BC layer as TBC layer. TBCs specimens
are heat exposed in an air at 1073, 1173 and 1273 K for 10, 50, 100 and 200 hours. The
microstructures of the as-deposited and heat exposed TBCs are observed by scanning electron
microscopy (SEM). Change of chemical composition in each layers are measured by energy
dispersive X-ray analysis (EDX) and electron probe micro analyzer (EPMA).
Results and Discussion Fig.1 shows the typical example of a polished transverse section of anas-deposited TBCs. TBC, BC and substrate are visible. After heat exposure at 1273 K for 100 h,
thermally grown oxide (TGO) layer forms between TBC and BC layer (Fig.2). Analysis of chemicalcomposition indicates that the TGO layer is mainly composed of Al2O3. The thickness of TGO layer
is increasing with the increase in heat exposure temperature and time. Al depleted zone forms at thevicinity of TGO layer in BC layer due to the formation of Al2O3 at TBC/BC interface. Further, newlayer has formed at the BC side and TiAl substrate side from the BC/substrate interface. It seems
that interdiffusion is occurring during heat exposure at the interface. Ti and Nb are detected in
CoNiCrAlY BC alloy and Co, Ni and Cr are observed in TiAl substrate.

Fig.1 Scanning electron micrograph of asdeposited TBCs.

Fig.2 Scanning electron micrograph of the TBCs
heat exposed at 1273 K for 100 h.
- 28 -

Lecture 012
Synthesis and Characterization of K2Ti6O13 Whisker by Flux Method
Yeon Bin Choi1, Jeong Hun Son1 and Dong Sik Bae1†
Department of Advanced Materials Science and Engineering, Chnagwon National University1
Department of Advanced Materials Science and Engineering, Changwon National University,
Changwon, Gyeongnam, 641-773, South Korea1
TEL: +82-55-275-5475

E-mail: dsbae7@chanwon.ac.kr

Abstract Potassium titanate whisker using for brake lining material in automotive brake systems.
K2Ti6O13 whisker are a major role in preventing light-hazardous materials to asbestos dust
generated during automobile braking and improves the wear resistance more than twice the asbestos
brake lining. K2Ti6O13 whisker have been synthesized by a flux method. The average size anddistribution of the synthesized K2Ti6O13 whisker can be controlled by mole ratio of potassium
precursor, reaction temperature and time. The average size of the synthesized K2Ti6O13 whisker was
about in the size range of 500nm to 1um and diameter range of 20 to 50nm. The size distribution of
the synthesized K2Ti6O13 whisker was uniform. The synthesized K2Ti6O13 whisker wascharacterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope(FE-SEM), Energy Dispersive X-ray Spectroscopy (EDS).
Experimental KOH, KNO3, K2CO3 concentration of condition 4, 5 was added to TiO2 and KCl
was added to improve morphology of whisker as a flux. The mixed powders were homogeneously
mixed by ball-milling or mixer. The mixed powder was placed in a box furnace, sintering at 850~1150℃ for 0.5~4 hours and then quenching at 950°C. After quenching, powder was washed forfive times using distilled water (D.I. Water) to remove KCl. Thereafter, it was dried at 100°C for 24hours.
Results and Discussion The aspect ratio of the synthesized K2Ti6O13 whisker was decreased
with adding potassium chloride as flux and quenching reactant. The measured aspect ratio of thesynthesized K2Ti6O13 whisker was less than 10 when reacted at condition 5. The average length of
the synthesized K2Ti6O13 whisker was about in the range of 1um to 10um. The average diameter ofthe synthesized K2Ti6O13 whisker was about in the range of 500nm to 1um.

Fig. 1. FE-SEM image of potassium titanate
whisker synthesized by Flux method atcondition 5 with flux X & quenching O

Fig. 2. FE-SEM image of potassium titanate
whisker synthesized by Flux method atcondition 5 with flux O & quenching O

References[1] M. A. Siddiquia, V. S. Chandel and A. Azam, ‘‘Comparative study of potassium hexatitanate(K2Ti6O13) whiskers prepared by sol–gel and solid state reaction routes’’, Appl Surf Sci. 258 (2012)7354.
[2] T. Endo, H. Nagayama, T. Sato and M. Shimada, ‘‘Crystal growth of poatassium titanates in thesystem K2O-Fe2O3-TiO2’’, J Cryst Growth. 78 (1986) 423.

- 29 -

Lecture 013
Effect of Preparation Methods on the Electrochemical
Performance of All-solid-state Li-S battery

Han Ul Choi, Ju Sung Jin, Hyung-Tae Lim*
School of Materials Science and Engineering, Changwon National University
20 Changwondaehak-ro, Changwon, Gyeongnam 641-773 Korea
TEL: +82-55-213-3716 E-mail: htaelim@changwon.ac.kr

Abstract
Lithium/sulfur (Li-S) batteries are one of the most promising rechargeable storage devices due totheir high energy density (~ 2, 500 Wh/kg), which is ~ 5 times higher than that of lithium ion
batteries1, 2). All-solid-state Li-S batteries were fabricated with lithium silicide anodes (Li4.4Si),
sulfide-based glass electrolyte (Li2S-P2S5), and sulfur composite cathode. The sulfur based
composite cathode was prepared by two methods; (Case 1) mortar-mixing and (Case 2) planetaryball milling at a rotation speed of 370 rev/min for 10min. SEM analysis results indicate that ‘Case
2’ method improved distribution of sulfur, carbon and solid electrolyte particles, with the reductionof particle size. This effect was reflected in impedance spectra, and eventually charge-discharge
capacity: the electrode/electrolyte interface resistance was reduced so that the averagecharge-discharge capacities increased in ‘Case 2’. Thus, the present work indicates the preparation
method of sulfur composite cathode profoundly affects the performance of solid state Li-S batteries.

(a)

(b)
Fig.2 Galvanostatic charge/discharge
voltage curves of Case 2

Fig.1 SEM Images of sulfur composite powders
prepared by Case 1 (a) and Case 2 (b)References
1) T. Kobayashi, Y. Imade, D. Shishihara, K. Homma, M. Nagao, R. Watanabe, T. Yokoi, A. Yamada, R.
Kanno and T. Tatsumi, J. Power Sources. 182, 621 (2008).

2) M. Nagao, A. Hayashi and M. Tatsumisago, Electrochim. Acta, 56, 6055 (2011).

- 30 -

Lecture 014
Control of Electron Coupled State in Superlattice of PbS Quantum Dots by
Replacing Ligands
Fumimasa Suetsugu, Keisuke Niwa, Kohki Mukai
Graduate School of Engineering, Yokohama National University79-5 Tokiwadai, Hodogaya-Ku, Kanagawa, 240-8501, Japan
TEL: +81--45-339-3853 E-mail: mukai-kohki-cv@ynu.ac.jp
Abstract We report that the emission wavelength of superlattice prepared by dense packing of
colloidal PbS quantum dots (QDs) became longer by replacing the ligands with shorter ones. The
dense packing was achieved by the aid of pyramidal hole array prepared on Si substrate using facet
selective etching. Emission energy shift was accompanied with the increase of emission lifetime.
These emission properties were attributed to the de-localization of electron wavefunction in the
ground state of QD superlattice.
Experimental We investigated chain lengths, replacement methods, and optical properties ofligands to be replaced. Chain lengths of various ligands were compared by using the calculation.
After the selection, replacement of ligands was performed. The successful replacement was
confirmed by fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy(TEM) . To compose superlattice film, PbS QDs were deposited in solvent into the pyramidal holearray prepared on Si substrate(Fig.1)[1]. The pyramidal hole array is effective to achieve QD orderingwith long periodicity. Scanning electron microscope and atomic force microscope were used toevaluate the arrangement of QDs. Photoluminescence (PL) spectra and emission lifetime were
measured by using conventional lock-in system and time correlation measurement system.
Results and Discussion As candidates of ligands to be replaced, n-butylamine (BA),2-methyl-2-propanol, pyridine (PD), octylamine, oleic acid (OA), trioctylphosphine, oleylamine(OLA) were studied. The calculation by the semi-empirical molecular orbital method and the energy
minimization method was done using the free software "Winmostar"[2]. As a result of the studies, weselected BA and PD, which are shorter than OA used in our previous work, and OLA, which are
longer than OA, for comparison. We first replaced ligands from OA to BA. We observed the QD
interval became shorten by TEM measument, and the peak appearance in FT-IR spectra, that suggests
the ligand replacement was successful. Then, we precipitated OA and BA treated QDs on the
pyramidal hole arrays for 3 days, respectively. As result of the PL measurement, we observed theemition peak shift for 190nm by forming films of BA-treated QDs, that was not clearly seen using
OA-treated QDs. We also confirmed the emition lifetime becoming longer by forming films of
BA-treated QDs and observed QDs ordering in the film. These results suggest that the dense packing
of BA-treated PbS QDs resulted in the de-localization of electrons at the ground state in QD
superlattice, rather than the mere coupling of neighboring ground-state electrons. We will also reportdetails including the results of other ligands.

Fig.1 Method to realize long periodic QD

Fig.2 PL spectra of BA-treated and OA-treatedstructure with pyramidal holes on Si substrate.

PbS QD in liquid and film, respectively.

References[1] K. Mukai et al., Semicond. Sci. Technol., vol.30, pp.044006 (2015)[2] X-Ability Co.,Ltd, https://winmostar.com/jp/- 31 -

Lecture 015
The effect of hydrogen sulfide(H2S) on sulfur poisoning of nickel-yttria stabilized
zirconia(Ni-YSZ) anode supported solid oxide fuel cells
Hyun Mi Lee, Hyung-Tae Lim*
School of Materials Science and Engineering, Changwon National University
20 Changwondaehak-ro, Changwon, Gyeongnam 641-773 korea
TEL: +82-55-213-3716
E-mail: htaelim@changwon.ac.kr
Abstract Solid oxide fuel cells(SOFCs) operate under various type of fuel, such as biogas andsyngas, due to their high operating temperature( >700℃) without the need of pre-reforming. H2S
poisoning is an important issue for solid oxide fuel cells operated with biogas and syngas 1-3). This
study investigates the effect of hydrogen sulfide (H2S) concentration of Ni/YSZ anode-supported
degradation rates of SOFCs. The electrochemical impedance spectra (EIS) of the cells were
measured in pure hydrogen fuel and compared to H2S additives (before poisoning). The
performance degradation was studied with concentration of H2S (0~50ppm) at 700℃ under aconstant current(500mA/cm2) condition. In all cases, the H2S contained in the fuel caused a rapid
drop in the cell performance (named 1st drop), followed by a slow and steady deterioration (named
2nd drop). In the 2nd drop section, the high concentration of H2S accelerated the voltage loss.
While, the voltage drop was not observed at the low H2S concentration (5ppm). For post-test
analyses, X-ray Diffraction Spectroscopy (XRD), scanning electron microscopy (SEM) with energy
dispersive X-ray spectroscopy (EDS), and Raman spectroscopy were used. Raman results indicate
nickel sulfides were formed in the anode layer, especially at the high H2S concentration. Thus, thedegradation of SOFCs under H2S containing fuel is attributed to the formation of the nickel sulfide
at Ni anode.
Constant Current Test - 3rd RIST cell
2500mA/cm

Cell Voltage (V)1.0

H2S 5ppm
H2S 10ppm
H2S 25ppm
H2S 50ppm

0.9

0.8

0.7

0

10

20

30

Time (h)4050

Fig.1 Constant current test with hydrogensulfide contained fuel respectively 5ppm,
10ppm, 25ppm, and 50ppm at 500mA/cm2

60

Fig.2 Raman spectra (A) anode(Ni-YSZ cermet)
after exposure to H2 containing 25ppm H2S, (B)anode(Ni-YSZ cermet) after exposure to H2
containing 10ppm H2S, (C) YSZ pellet, and (D)anode(Ni-YSZ cermet)

References
1) T. S. Li, H. Miao, T. Chen, W. G. Wang, and C. Xu, J. Electrochem. Soc, 156, 1383 (2009)2) B.C.H Steele, A. Heinzel, Nature, 414, 345 (2001)
3) J. Dong, Z. Cheng, S. Zha, M. Liu, J. Power Sources, 516, 461 (2006)- 32 -

Lecture 016
Competition Behavior Between Defect Propagation and Self-Healing under High
Temperature Creep in Fiber-Reinforced Self-Healing Ceramics
Jang Won LEE1, Wataru NAKAO2
1

Graduate School of Engineering, 2Faculty of Engineering

Yokohama National University, 79-5, Tokiwadai, Hodogayaku, Yokohama 240-8501, Japan
TEL: +81-80-9803-3331
E-mail: Lee-jangwon-dp@ynu.jp
Abstract Fiber-reinforced self-healing ceramics1) exhibit unique damage tolerance, thereby,
anticipated to be next generation structural material, such as turbine blades in jet engine. Its damage
tolerance originates from the competition between crack propagation and crack re-bonding due toself-healing. Self-healing function is generated from the high temperature oxidation of healing agent,
which is located at the interface between ceramic fiber bundle and matrix, thus, influenced strongly
by service temperature. In order to actualize the components made of the fiber-reinforced ceramics,
the fracture criteria with the competition is necessary.
Experimental In the present study, the creep fracture behaviour of the fiber-reinforced self-healing
ceramics was investigated at high temperatures. From the time change in displacement under tensilestress, the competition behaviour between crack propagation and crack re-bonding was discussed.
The used sample is typical fiber-reinforced ceramics, which consists of alumina fiber bundle, alumina
matrix and SiC interlayer as healing agent.
Results and Discussion Fig. 1 shows the creep curves of the sample at 1000 oC. As shown infigure, when tensile stress is 160MPa, the specimen fractured after 6 s. On the other hand, under
tensile stress of 137 MPa the creep rate reached to 0 and the specimen could survive for more than
300 h. And, under tensile stress of 150MPa the creep rate reached to 0 and the specimen survived
for 1000h. The specimen has cracking strength at 1000 oC of 47 MPa and final fracture strength of
147 MPa, thus, the creep behaviour was found to include the competition between crack propagationand crack re-bonding due to self-healing. Moreover, creep strength of 137 MPa is quite high,compared to the final fracture strength, therefore, it was found that self-healing function affects the
creep strength of self-healing materials strongly.

Fig.1 Creep curves of the fiber-reinforced self-healing ceramics at 1000oC

References
1) NAKAO, W, HAGA, Y,: Japanese Patent, 5788309, (2015)- 33 -

Memo- 34 -

- 35 -

Organized by
Yokohama National University, Department of Solid State Materials and Eng., Japan
Changwon National University, Department of Nano and Advanced Materials Eng., Korea
Supported by
Yokohama National University, Japan
Changwon National University, Korea- 36 -