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Nuclear Engineering & Radiological Science, University of Michigan

1(Li21-The University of Michigan HP
Dr. Fei Gao
https://ners.engin.umich.edu/people/gao-fei/

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Nuclear Engineering & Radiological Science, University of Michigan1(Li21-ab-initio“If you want to learn computational material science, you got the right person. Dr. Gao is legendary.”3 / 18

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―LAMMPS

4 / 18⚫ 第4族遷移金属ホウ化物は、高温特性から様々な技術への応用が期待されている。
期待される応用

Arc-jettesting ofZrB2-based
CMC for areusablerocket[4].

⚫

>3000
>20 GPa⚫

>60 W/m·K
4.5-11.2 g/cm3[2]M.M. Opeka, et al., JMater Sci 39 (2004) 5887–5904.
[3]W.G. Fahrenholtz, et al.,Scr Mater 129 (2017) 94–99.
[4]R. Savino, et al., Advancesin Applied Ceramics 117(2018) s9–s18.
[5]A. Nisar, et al., Ceram Int
48 (2022) 8852–8881.
[6]L. Silvestroni, et al., J EurCeram Soc 38 (2018) 2467–2476.

etc[1] B.R. Golla, et al., Prog MaterSci 111 (2020) 100651.

etc⚫ 緻密化プロセスにおいて厳しい条件を要する。
一般的なホウ化物の焼結条件

温度>1800

圧力>30 MPa 焼結法が限定される。
••Hot Press
Spark plasma sintering→ 形状に制限

結晶粒の粗大化••

母相複合材における強化材→ 機械的特性の劣化(e.g., fiber & whisker)

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焼結助剤の添加による焼結温度低下の試み⚫

機械的合金化 Ti-B 共晶合金助剤 (our previous work[10])[7] D. Aĝaoĝullari et al., J. Eur. Ceram. Soc. 32 (2012) 1949–
1956. [8] C. Yang, et al., Materials (Basel). 7 (2014) 7105–7117. [9] Z.H. Zhang et al., Scr. Mater. 66 (2012) 167–170.

Z.H. Zhang et al.
“ TiBによりTiB2粒子の結合が強化された.”[9]6 / 18

Professor Gao’s Group, US分子動力学法による原子レベルシミュレーション(Angstrom ~ submicron scale)

Professor Kasada’s Group, Japan

FIBおよびナノインデンターによる超微小試験(micrometer scale)7 / 18

Professor Gao’s Group, US

1. TiB-TiB2e.g., LAMMPS commands, boundary conditions, scales, etc.

2.
e.g., the interior of TiB or TiB2 crystal, interface, etc.

分子動力学法による原子レベルシミュレーション(Angstrom ~ submicron scale)3.

.(

7 / 18)1.
Modelsa2c a1 TiB2 {001}2.

TiB2 (Hexagonal)

ca2

TiB (Orthorhombic)

a1 TiB {100}2cabc
TiB {001}

ab

TiB {100}

Conditions

Code: LAMMPS code
Interatomic Potential: the second nearest-neighbor modified

Stress type: shear/tensile
Loading: constant speed of 5 m/s in Y or X direction

embedded atom method (S. Attarian et al.
Comput. Mater. Sci. 2022)
Temperature: 300 K (NPT ensemble)
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Side viewccb

TiB {001}

a-58

Total potential energy (keV)

Total potential energy (keV)-59-60-61-62-63-64-65-66
0200Time (ps)TiB {100}-58

Peak-59.84 keV-59b

a400-60-61

Peak-59.86 keV-62-63-64-65-660

Stress distribution YY

200Time (ps)400

Stress distribution YY
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a2cca1 TiB

2 {001}

a2

TiB2 {100}-60-60-60.5

-60.5

-61

Total potential energy (keV)-61

Total potential energy (keV)

a1-61.5-62-62.5

Peak-61.07 keV-63-63.5-64-64.5-65
0100

200Time (ps)

300

400

Stress distribution YY-61.5

Peak-63.93 keV-62-62.5-63-63.5-64-64.5-65
0100

200Time (ps)

300

400

Stress distribution YY
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1.

2.

Interfacial models
TiB-TiB2
a2a1TiB2 {100}ccaTiB-TiB2’a2

TiB {001}

a2

TiB2 {001}{001}{100} c a1c bb

TiB2-TiB2’a{100}{100}{100}{001}c a1a2

TiB {001}

TiB2 {001}ca1

TiB2 {100}11 / 18

1.

2.

Interfacial models
TiB-TiB2a2a1

TiB2 {100}cca{001}{100}bTiB {001}

TiB2
X, Y, Z
Unit cells:
XXX, YYY, ZZZ
Dimension (Å): XXX.X, YYY.Y, ZZZ.Z
TiB
X, Y, Z
Unit cells:
XXX, YYY, ZZZ
Dimension (Å): XXX.X, YYY.Y, ZZZ.Z

Conditions
Code: LAMMPS code
Interatomic Potential: the second
nearest-neighbor modified
embedded atom method (S.
Attarian et al. Comput. Mater.
Sci. 2022)
Temperature: 300 K (NPTensemble)
Stress type: shear/tensile
Loading: constant speed of 5 m/s
in Y or X direction

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1.

2.

Interfacial models
TiB-TiB2’a2

TiB2 {001}c a1
c ba{100}{100}TiB {001}

TiB2
X, Y, Z
Unit cells:
XXX, YYY, ZZZ
Dimension (Å): XXX.X, YYY.Y, ZZZ.Z
TiB
X, Y, Z
Unit cells:XXX, YYY, ZZZ
Dimension (Å): XXX.X, YYY.Y, ZZZ.ZConditions
Code: LAMMPS code
Interatomic Potential: the second
nearest-neighbor modified
embedded atom method (S.
Attarian et al. Comput. Mater.
Sci. 2022)
Temperature: 300 K (NPTensemble)
Stress type: shear/tensile
Loading: constant speed of 5 m/s
in Y or X direction

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TiB-TiB2’

TiB-TiB2a2ca1

TiB2 {100}c ba TiB {001}

{001}
{100}

a2 TiB2 {001}{100}c a1{100}c ba TiB {001}

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TiB-TiB2’

TiB-TiB2
a2ca1

TiB2 {100}c ba TiB {001}{001}{100}a2 TiB2 {001}{100}c a1{100}c ba TiB {001}14 / 18

TiB-TiB2a2ca1

TiB2 {100}c ba TiB {001}

{001}
{100}

TiB or TiB2

TiB-TiB2’
a2 TiB2 {001}{100}c a1{100}c ba TiB {001}TiB TiB2TiB”

TiB2

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Ann ArborAnn Arbor”Michigan Memorial
Phoenix
Project””Harlan Hatcher
Graduate Library”

ICACC2023

17 / 18✓✓✓Photo ”Michigan Union”

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