㜞ᒝᐲ࡜ࠗࡦࡄࠗࡊ↪㍑ߩ㜞ㅦ߈ⵚવ᠞ᛶ᛫ߩേ⊛᷹ቯ㩷⎇ⓥઍ⴫⠪㩷 ᧲੩ᄢቇᄢቇ㒮Ꮏቇ♽⎇ⓥ⑼䉲䉴䊁䊛ഃᚑቇኾ᡹㩷 ☿㘵ේ๟ੑ㩷㩷䋱䋮✜⸒㩷
21 ਎♿ߪ᳇૕ࠛࡀ࡞ࠡ࡯ߩᤨઍߣ⸒ࠊࠇߡ߅ࠅ‫ޔ‬਎⇇⊛ߦᄤὼࠟࠬߩ೑↪߇᜛ᄢߒ‫ޔ‬዁᧪⊛ߦߪ᳓⚛ࠟࠬ೑↪߳ᄌㆫߒߡ޿ߊ߽ߩߣ੍ᗐߐࠇߡ޿ࠆ‫ߦࠇߎޕ‬๭ᔕߒߡ‫ޔ‬㜞࿶ᄤὼࠟࠬࡄࠗࡊ࡜ࠗࡦߩᑪ⸳ߣ⸘↹߇ᚒ߇࿖ࠍ฽߻਎⇇ฦ࿖ߢዷ㐿ߐࠇߡ޿ࠆ‫ࠍࠇߎޕ‬ታ⃻ߔࠆߚ߼ߦ‫ޔ‬㋕㍑ฦ␠ߢߪ㜞ᒝᐲ࡜ࠗࡦࡄࠗࡊ↪㍑߇㐿⊒ߐࠇߡ޿ࠆ‫ޕ‬ 㜞࿶࡮㜞ᒝᐲࠟࠬࡄࠗࡊ࡜ࠗࡦߩା㗬ᕈ⏕଻ߪ༛✕ߩ㊀ⷐ⺖㗴ߢ޽ࠆ‫ߩߎޕ‬ਛߢᦨ߽㊀ⷐߥ߽ߩߪ㜞ㅦਇ቟ቯᑧᕈ⎕უ㧔100m/s એ਄ߩ㜞ㅦߢ߈ⵚ߇㐳〒㔌વ᠞ߔࠆ㧕ࠍ㒐ᱛߔࠆߎߣߢ޽ࠅ‫ߦߢ߹ࠇߎޔ‬⒳‫⹏ߩޘ‬ଔᚻᴺ߇⏕┙ߐࠇߡ޿ࠆ㪲㪈㪴‫޿ߥߦߢ߹ࠇߎޔ߇ࠈߎߣޕ‬㜞࿶࡮㜞ᒝᐲߩࡄࠗࡊ࡜ࠗࡦߢߪᓥ᧪ߩᚻᴺߢߪ‫♖ޔ‬ᐲࠃ޿⹏ଔ߇ߢ߈ߥ޿ߎߣ߇ᜰ៰ߐ
ࠇߡ߅ࠅ‫ޔ‬ᣧᕆߥ⸃᳿߇ᔅⷐߢ޽ࠆ㪲㪉㪴‫ޕ‬ ᓥ᧪ߩ㜞ㅦਇ቟ቯᑧᕈ⎕უߦኻߔࠆ⹏ଔߪඨℂ⺰࡮ඨ⚻㛎⊛ߥ߽ߩߢ޽ࠅ‫ࠗࡄࡦࠗ࡜ޔ‬ࡊ᧚ߩᑧᕈ߈ⵚવ᠞ᛶ᛫߽ࠪࡖ࡞ࡇ࡯ⴣ᠄⹜㛎߿ DWTT㧔Drop Weight Tear Test㧕⹜㛎ߦࠃࠆๆ෼ࠛࡀ࡞ࠡ࡯ࠍᜰᮡߣߒߡ޿ࠆ‫ߡ޿↪ࠍ࠲࡯ࡔ࡜ࡄߩࠄࠇߎޕ‬ታᄢ⹜㛎ߩ࠺࡯࠲ࠍᢛℂߒߡ޿ࠆ߇‫⚻ޔ‬㛎⊛ߥⷐ⚛߇ᄙߊ‫ޔ‬ᓥ᧪એ਄ߩ㜞ᒝᐲ࡮㜞࿶ࡄࠗࡊ࡜ࠗࡦࠍኻ⽎ߣߔࠆ႐วߩ♖ᐲૐਅߩේ࿃ߩ߭ߣߟߣ⠨߃ࠄࠇࠆ‫ޕ‬ ᧄ⎇ⓥߢߪ‫ޔ‬⎕უജቇߦၮߠ޿ߚ㜞ㅦਇ቟ቯᑧᕈ⎕უߩ⹏ଔᚻᴺࠍ⏕┙ߔࠆߚ߼ߩ╙৻ᱠߣߒߡ‫ޔ‬⎕უജቇᜰᮡࠍ↪޿ߡ࡜ࠗࡦࡄࠗࡊ᧚ߩᑧᕈ߈ⵚવ᠞ᛶ᛫ࠍ⹏ଔߒ‫․ߩߘޔ‬ᕈߦߟ޿ߡ⠨ኤߔࠆ߽ߩߢ޽ࠆ‫ޕ‬㩷䋲䋮⸃ᨆᣇᴺ㩷㩷 ৻⥸䈮䇮㜞ᒝᐲ䊶㜞ᑧᕈ㍑᧚䈱ᑧᕈ䈐ⵚવ᠞䈲ᄢⷙᮨ႟ᕈᄌᒻ䉕઻䈉႐ว䈏ᄙ䈒䇮㕖✢ᒻ⎕უജቇ䈱ㆡ↪䈏ᔅⷐ䈪䈅䉎䇯ᧄ⎇ⓥ䈪䈲䇮㕖✢ᒻ⎕უജቇ䊌䊤䊜䊷䉺䈫䈚䈩 㪡 Ⓧಽ㪲㪊㪴䉕ㆡ↪䈚䇮㪡 Ⓧಽ䈮ၮ䈨䈇䈢ᑧᕈ䈐ⵚᛶ᛫ᦛ✢㩿㪡㪄㪩 ᦛ✢㪀䈮䉋䉍䊤䉟䊮䊌䉟䊒᧚䈱⹏ଔ䉕ⴕ䈉䈖䈫䈫䈚䈢䇯㩷㪞㪸㫉㫎㫆㫆㪻㩷㪲㪋㪴䈲䇮ಾᰳઃᦛ䈕⹜㛎䈮䈧䈇䈩䇮ၮᧄ⊛䈭㪡㩷 Ⓧಽ▚ቯᑼ䈎䉌䇮䈐ⵚᚑ㐳䈮䉋䉎䉣䊈䊦䉩䊷ᶖ⾌䉕⠨ᘦ䈚䈢ᰴᑼ䈱㪡㩷 Ⓧಽ▚ቯᑼ䉕ዉ಴䈚䈢䇯㩷Jn䈖䈖䈪䇮㪮㩷 䈲⹜㛎㑆䈮⹜㛎J n1᏷䇮㪙㩷 䈲⹜㛎W  an2U 4㩷 㩷 㩷 㩷 㩷 㩷 㩷 㩷 㩷 㩷 㩷 㩷 㩷 㩷 㩿㪈㪀㩷W  an1 B(W  an1 )᧼ෘ䇮㪸㩷 䈲䈐ⵚ㐳䈘䇮㪬㪋䈲䈐ⵚ䈏㪸㫅㪄㪈䈎䉌㪸㫅䉁䈪ᚑ㐳䈜䉎䈮૞↪䈜䉎઀੐䈪䈅䉎䋨㪝㫀㪾㪅㪈䋩䇯䈖䉏䉕䉅䈫䈮䇮㪡㪄㪩㩷 ᦛ✢䉕ዉ䈒ᓸಽᣇ⒟ᑼ䉕ᰴᑼ㧙㧙䈱䉋䈉䈮᳞䉄䈢䇯㩷dJd'

J da2P㩷 㩷 㩷 㩷 㩿㪉㪀㩷W  a d' B (W  a )䈖䈖䈪䇮㪧䇮䈍䉋䈶䇮㰱䈲ฦ䇱䇮ಾᰳ䈐ઃ䈐䋳ὐᦛ䈕⹜㛎䈮૞↪䈜䉎⩄㊀䈫ᄌ૏䈪䈅䉎䇯㩷ᑼ㩿㪉㪀䉕૶䈋䈳䇮㪧㪄㰱ᦛ✢䈫㪸㪄㰱ᦛ✢䉕ታ㛎䈮䉋
Fig.1 Three-point bend specimen䉍᳞䉄䉏䈳䇮㪡㪄㪩㩷 ᦛ✢䉕▚ቯ䈪䈐䉎䇯㩷㩷䋳䋮ታ㛎ᣇᴺ㩷
㧟㧚㧝 േ⊛⹜㛎ᣇᴺḰ㕒⊛⽶⩄ߦኻߔࠆᑧᕈ߈ⵚવ᠞ᛶ᛫ߩ᷹ቯߦ㑐ߒߡߪᣢߦታ㛎ᣇᴺ߇⏕┙ߐࠇߡ޿ࠆ‫ޕ‬৻ᣇ‫ޔ‬േ⊛⽶⩄ߦኻߔࠆ⹜㛎ᴺߦ㑐ߒߡߪ⏕┙ߐࠇߚ߽ߩߪሽ࿷ߒߥ޿‫⎇ᧄޕ‬ⓥߢߪ‫⪭ޔ‬㊀⹜㛎ᯏߦേ⊛⸘᷹ߩᯏ⢻ࠍઃߌട߃ࠆߎߣߦࠃࠅ‫ޔ‬㜞ㅦᑧᕈ߈ⵚવ᠞ᛶ᛫ᦛ✢ߩ⸘᷹ࠍน⢻ߣߔࠆ⎕უ⹜㛎ࠪࠬ࠹ࡓࠍ᭴▽ߒߚ‫ޕ‬
Fig.2 ߦ‫⹜ޔ‬㛎ᯏߩᄖⷰࠍ␜ߔ‫⪭ޕ‬㍝ߪ⚂ 100
㨪200kg ߩ▸࿐ߢ‫⪭ޔ‬ਅ㜞ߐߪᦨᄢ⚂ 3m ߹ߢ⺞ᢛน⢻ߢ޽ࠆ‫ᦨޕ‬ᄢๆ෼ࠛࡀ࡞ࠡ࡯ߪ⚂6,000J ߢ޽ࠅ‫᧼ޔ‬ෘ߇ 20mm ⒟ᐲ߹ߢߩ⹜㛎ࠍଏߔࠆߎߣ߇ߢ߈ࠆ‫⩄ࠅࠃߦ࡞࠮࠼࡯ࡠޕ‬㊀ࠍേ⊛ߦ⸘᷹ߔࠆߣߣ߽ߦ‫ࠩ࡯࡟ޔ‬ᄌ૏⸘ߦࠃࠅ⹜㛎ߦਈ߃ࠆᄌ૏ࠍേ⊛ߦ⸘᷹ߔࠆ‫ޕ‬ਔ⸘᷹୯߆ࠄ‫ޔ‬㪧㪄㰱ᦛ✢ࠍᓧࠆߎߣ߇ߢ߈ࠆ‫ޕ‬৻ᣇ‫ޔ‬㜞ㅦࠞࡔ࡜ߦࠃࠅ⹜㛎ߩ߈ⵚવ᠞㐳ߐࠍേ⊛ߦ⸘᷹ߔࠆߎߣߦࠃࠅ‫ޔ‬㪸㪄㰱ᦛ✢䉕᳞䉄䉎䈖䈫䈮䈚䈢䇯㩷Ḱ㕒⊛‫ޔ‬෸߮‫ޔ‬േ⊛⹜㛎ߦࠃࠅ࡜ࠗࡦࡄࠗࡊ᧚ߩᑧᕈ߈ⵚવ᠞ᛶ᛫ࠍ⸘᷹ߒ‫⹜ޔ‬㛎ᓟߩ⎕㕙ࠍ SEM ╬ߩㅢᏱߩᣇᴺߦࠃࠅⷰኤߒߚ‫ޕ‬

Fig.2 Drop-weight test machine㧟㧚㧞 ଏ⹜㍑
ଏ⹜㍑ߪ‫ޔ‬ᄖᓘ߇ 267mm‫ޔ‬ෘߐ߇ 6mm ߩ API 5LX 65mod.㍑▤ߢ޽ࠆ‫ޕ‬Table 1 ߦᯏ᪾⊛․ᕈࠍ␜ߔ‫ޕ‬Fig.3 ߦ␜ߔಾᰳ߈ઃ߈ 3 ὐᦛߍ⹜㛎

ࠍ㍑▤๟ᣇะߦណขߒߚ‫ޕ‬ಾᰳ߈ߩవ┵ߪ 0.2mm ᏷ߩᯏ᪾ടᎿߣߒߚ‫ޕ‬

Table 1 Mechanical property of tested steel
YS (MPa)TS (MPa)El (%)

vE(0͠) (J)

503

659

2770

(Transverse direction)㧙㧙

200䋴䋮ታ㛎⚿ᨐ㩷10㩷 㪝㫀㪾㪅㪋 䈮䇮Ḱ㕒⊛⹜㛎䇮෸䈶䇮േ

ѳ6100

10035⊛⹜㛎䈮䈍䈔䉎タ⩄ㅜਛ䈱⹜㛎๟ᣇะ䈱ᄌᒻ䈫䈐ⵚવ᠞䈱᜼േ䈱଀䉕␜䈜䇯㩷

Fig.3 Three point bend specimen (unit in mm)

㩷 㪝㫀㪾㪅㪌㩿㪸㪀㪃㩿㪹㪀䈮䇮Ḱ㕒⊛⹜㛎䈮䈍䈔䉎 㪧㪄㰱ᦛ✢ߣ 㪸㪄㰱ᦛ✢䉕␜䈜䇯䉁䈢䇮㪝㫀㪾㪅㪍㩿㪸㪀㪃㩿㪹㪀䈮䇮േ⊛⹜㛎䈮䈍䈔䉎 㪧㪄㰱ᦛ✢ߣ 㪸㪄㰱ᦛ✢䉕␜䈜䇯㜞ㅦ䉦䊜䊤䈮䉋䉍᷹ ቯ 䈚 䈢 䈐 ⵚ વ ㅦ ᐲ 䈲㪭㪔㪊㪅㪇㫄㪆㫊 䈪䈅䈦䈢䇯㩷㩷 㪝㫀㪾㪅㪎 䈮䇮⸘᷹⚿ᨐ䉕䉅䈫䈮䇮ᑼ㩿㪉㪀䈎䉌᳞䉄䈢 㪡㪄㪩 ᦛ✢䉕␜䈜 䇯 䈐 ⵚ વ ᠞ 〒 㔌 䈏 ⚂ 㪈㪇 䌾㪈㪌㫄㫄 䈱▸࿐䈪ᛶ᛫୯䈲䈾䈿৻ቯ䈫䈭䉎䈖䈫䈏䉒䈎䉎䇯䈖䈱୯䉕 㪡㫇㫃㪸㫋㪼㫌 䈫䈚䈩䇮Ḱ㕒⊛⹜㛎䇮෸䈶䇮േ⊛⹜㛎䈮䈍䈇䈩⪭㍝㜞䈘䉕ᄌൻ䈘䈞䉎䈖䈫䈮䉋䉍䈐ⵚવ᠞ㅦᐲ䉕ᄌൻ䈘䈞䈢႐ว䈱୯(a) quasi-static䉕᳞䉄䈢䇯⚿ᨐ䉕 㪝㫀㪾㪅㪏 䈮␜䈜䇯(b) dynamic

Fig.4 Deformation and crack propagation behaviors.

Ḱ㕒⊛䇮෸䈶䇮䈐ⵚવ᠞ㅦᐲ䈏⚂ 㪋㪅㪌㫄㪆㫊 એਅ䈱▸࿐䈪䈲 㪡㫇㫃㪸㫋㪼㫌䈲䈾䈿৻ቯ䈪䈅䈦䈢䇯㩷
0.020

Load MN
Load(MN)

㪟㪣0.015

Length mCrack Length(m)㪟㪣0.025

0.010

0.005

0.000
0.000

0.005

0.010

㪟㪣

0.015

0.020

Displacementm
Displacement(m)

0.020
0.015
0.010
0.005
0.000
0.000

0.005

0.010

㪟㪣

0.015

Displacementm
Displacement(m)Fig.5 Load-displacement curve and crack length-displacement curve, quasi-static.

㩷㩷㩷㧙㧙0.020

0.035㪟㪣

0.025

Load(MN)
Load MN㪟㪣

Length m
Crack Length(m)

0.030
0.025
0.020
0.015
0.010
0.005
0.000
0.000

0.005

0.010

0.015

㪟㪣
0.020

0.025

0.020
0.015
0.010

0.000
0.000

0.030

㪟㪣

0.005

0.005

Displacementm
Displacement(m)

0.010

0.015

0.020

Displacementm
Displacement(m)Fig.6 Load-displacement curve and crack length-displacement curve, dynamic.

3.0

2.0

1.5

1.0

0.5

0.0
0.000

0.002

0.004

0.006

0.008

0.010

㪟㪣

0.012

Ductile Crack Length(m)Length m

2.0
1.5
1.0
0.5
0.0
0.000

0.014

Jplateau

V= 3.0 m/s

2.5

㪟㪣

J㪄 Integral MPa 䍵m JJIntegral(MPa㨯m)

Jplateau㪟㪣J㪄 Integral MPa 䍵m JJJIntegral(MPa㨯m)

2.5

0.002

0.004

0.006

0.008

0.010

㪟㪣

0.012

Ductile Crack Length(m)Length m'a(a) quasi-static

0.014'a(b) dynamic (V=3.0m/s)
Fig.7 J-R curves䋵䋮⠨ኤ㩷㩷 㪝㫀㪾㪅㪏 䈮␜䈚䈢䈫䈍䉍䇮䈐ⵚ࿐䈪䈲䇮㪡㪄㪩 ᦛ✢䈱㘻๺୯䈱䈐ⵚવ᠞ㅦᐲଐሽᕈ䈲䈾䈫䉖䈬⹺䉄䉌䉏䈭䈎䈦䈢䇯䈫䈖䉐䈪䇮䈐ⵚવ᠞ㅦᐲ䈏ᄢ䈐䈒䈭䉎䈫䇮䈐ⵚవ┵ㄭற႟ᕈၞ䈱ᱡㅦᐲ䈏਄᣹䈜䉎䈖䈫䈮઻䈇䇮J㪉㪅㪌J -plateau (MPa m)

વ᠞ㅦᐲ䈏Ყセ⊛ዊ䈘䈇▸

㪊

㪉

㪈㪅㪌

㪈

㪇㪅㪌

㪇
㪇

㪇㪅㪌

ㄭற䈱ᄌᒻ䈱⒟ᐲ䈣䈔䈪䈭䈒䇮

㪈㪅㪌

㪉

㪉㪅㪌

㪊

Crack Velocity (m/s)

㒠ફᒝᐲ䈲਄᣹䈜䉎䈖䈫䈏੍ᗐ䈘䉏䉎䇯㪡 Ⓧಽ䈲䈐ⵚవ┵

㪈

㪊㪅㪌

㪋

㪋㪅㪌

V

Fig.8 Dependence of J-plateau value on crack velocity.

᧚ᢱ䈱ᄌᒻᛶ᛫䈮䉅ଐሽ䈜䉎䇯䈖䈖䈪䈲䇮◲න䈱䈢䉄䈮䇮䈐ⵚవ┵ㄭறᄌᒻ䈱ᜰᮡ䈫䈚䈩㪚㪫㪦㪘㩿㪚㫉㪸㪺㫂㪄㪫㫀㫇㩷㪦㫇㪼㫅㫀㫅㪾㩷㪘㫅㪾㫃㪼䋻䈐ⵚవ┵㐿ญⷺ㪀䉕ណ䉍䇮᧚ᢱ䈱ᄌᒻᛶ᛫䈫䈚䈩䇮⹜㛎䈮䈍䈔䉎ᦨᄢ⩄㊀䋨䈐ⵚવ᠞㐿ᆎὐ䈮䈾䈿৻⥌䈜䉎䈫⠨䈋䉎䈖䈫䈏䈪䈐䉎䋩䉕ណ䉍䇮䈐ⵚવ᠞ㅦᐲ䈮㧙㧙㪉㪍㪇㪅㪇㪉㪍ኤ䈎䉌䇮વ᠞ਛ䈱䈐ⵚవ┵䈎䉌⚂㪉㪋㪇㪅㪇㪉㪌㪌㫄㫄 䈱▸࿐䈮䈍䈔䉎㐿ญⷺᐲ䈎㪉㪉㪇㪅㪇㪉㪋㪉㪇㪇㪅㪇㪉㪊㪈㪏㪇㪅㪇㪉㪉㪈㪍㪇㪅㪇㪉㪈㪈㪋㪇㪅㪇㪉䈢䇯ਔ⠪䈱⋧ਸ਼૞↪䈮䉋䉍 㪡㫇㫃㪸㫋㪼㫌㪈㪉㪇㪅㪇㪈㪐䈏䈐ⵚવ᠞ㅦᐲ䈮ଐሽ䈚䈭䈇⚿㪈㪇䉌᳞䉄䈢䇯⚿ᨐ䉕 㪝㫀㪾㪅㪐 䈮␜䈜䇯䈐ⵚવ᠞ㅦᐲ਄᣹䈮઻䈇䇮ᦨᄢ⩄㊀䈲਄᣹䈚䇮㪚㪫㪦㪘 䈲ᷫዋ䈚

CTOA(degree)㪚㪫㪦㪘㩿㫦㪀

䈪䇮㪚㪫㪦㪘 䈲䇮㪝㫀㪾㪅㪋 䈫ห᭽䈭ⷰ㪇㪅㪇㪈㪏㪇㪇㪅㪌㪈㩷 ਄⸥䈱⚿ᨐ䈎䉌䇮䈐ⵚવ᠞ㅦᐲ䈏਄᣹䈜䉎䈾䈬䇮㪚㪫㪦㪘 䈏ᷫዋ㪈㪅㪌㪉㪉㪅㪌㪊㪊㪅㪌㪋㪋㪅㪌䈐ⵚㅴዷㅦᐲ㩿㫄㪆㫊㪀
Crack Velocity (m/s)ᨐ䈏ᓧ䉌䉏䈢䉅䈱䈫⠨䈋䉎䈖䈫䈏䈪䈐䉎䇯㩷Max.
Load (MN)ᦨᄢ⩄㊀㩿㪤㪥㪀

䉋䉎ਔ⠪䈱ᄌൻ䉕⺞ᩏ䈚䈢䇯䈖䈖Fig.9 Dependence of CTOA and maximum loadon crack velocity䈜䉎䈖䈫䈏᣿䉌䈎䈫䈭䈦䈢䇯䈖䈱ℂ↱䉕⸃᣿䈜䉎䈢䉄䈮䇮ᑧᕈ䈐ⵚ⎕㕙䈱 㪪㪜㪤 ⷰኤ䉕ታᣉ䈚䈢䇯ᑧᕈ䈐ⵚ䈲᧼ෘ䈱䈾䈿ో૕䈮ਗ਼䈦䈩 㪋㪌㫦䈱䈞䉖ᢿ⎕უ䉕๒䈚䈩䈇䈢䈱䈪䇮䈖䈱ㇱಽ䉕ⷰኤ䈚䈢䇯⚿ᨐ䉕 㪝㫀㪾㪅㪈㪇 䈮␜䈜䇯⎕㕙䈲䈜䈼䈩䊂䉞䊮䊒䊦䉕๒䈚䈩䈇䈢䇯䈐ⵚવ᠞ㅦᐲ䈏਄᣹䈜䉎䈮ᓥ䈦䈩䇮䊂䉞䊮䊒䊦ᓘ䈏ዊ䈘䈒䈭䈦䈩䈇䉎௑ะ䈏⹺䉄䉌䉏䈢䇯䈘䉌䈮䇮䋳ᰴర⸘᷹ 㪪㪜㪤 䈮䉋䉍ห䈛⎕㕙䈱ⷰኤ䉕ⴕ䈦䈢䇯⚿ᨐ䉕 㪝㫀㪾㪅㪈㪈 䈮␜䈜䇯䈖䉏䉌䈱ⷰኤ⚿ᨐ䈎䉌䇮䈐ⵚવ᠞ㅦᐲ䈏਄᣹䈜䉎䈾䈬䇮䊂䉞䊮䊒䊦䈏ᵻ䈒䈭䈦䈩䈇䉎䈖䈫䈏䉒䈎䉎䇯䈖䉏䉌䈱ⷰኤ⚿ᨐ䈎䉌䇮䈐ⵚવ᠞䈮઻䈉䈐ⵚవ┵ㄭற䈱ᱡ䈲䈐ⵚવ᠞ㅦᐲ䈏ᄢ䈐䈇䈾䈬ૐਅ䈜䉎น⢻ᕈ䈏␜ໂ䈘䉏䉎䇯䈖䉏䈏 㪚㪫㪦㪘䈱䈐ⵚવ᠞ㅦᐲଐሽᕈ䈱ᄢ䈐䈭ේ࿃䈪䈅䉎䈫ផኤ䈘䉏䉎䇯䈐ⵚવ᠞ㅦᐲ਄᣹䈮䉋䉍ᑧᕈ⎕㕙਄䈱䊂䉞䊮䊒䊦䈏ዊ䈘䈒䇮਌䈧䇮ᵻ䈒䈭䉎ේ࿃䈲᣿䉌䈎䈪䈲䈭䈇䈏䇮ᱡㅦᐲ਄᣹䈮䉋䉎㒠ફᒝᐲ䈱਄᣹䈮䉋䉍੺࿷‛䉇╙ੑ⋧䈫࿾㋕⇇㕙䈮૞↪䈜䉎೸㔌ᔕജ䈏਄᣹䈚䇮䊂䉞䊮䊒䊦↢ᚑ䈏ଦㅴ䈘䉏䈢䈖䈫䈏ផኤ䈘䉏䉎䇯⹦⚦䈱ᬌ⸛䈏ᔅⷐ䈪䈅䉎䇯㩷㩷 ታ㓙䈱䊌䉟䊒䊤䉟䊮䈮䈍䈔䉎ᑧᕈ⎕უ䈱વ᠞ㅦᐲ䈲 㪈㪇㪇㫄㪆㫊 એ਄䈪䈅䉍䇮ᧄ⎇ⓥ䈪䈲⸘᷹䈪䈐䈭䈇ㅦᐲ▸࿐䈪䈅䉎䇯䈖䈱䉋䈉䈭ㅦᐲၞ䈮䈍䈔䉎䊂䉞䊮䊒䊦↢ᚑ䉇䈠䉏䈮઻䈉 㪚㪫㪦㪘 䈱ᄌൻ䉕⹏ଔ䈜䉎ᔅⷐ䈏䈅䉎䇯䈘䉌䈮䇮႟ᕈᵄ਄㒢ㅦᐲ䈮ẋㄭ䈜䉎䈖䈫䈮䉋䉍䇮䈐ⵚవ┵ㄭற䈱႟ᕈᄌᒻ᜼േ䈏ᧄ⎇ⓥ䈱䉋䈉䈭ૐㅦᐲၞ䈎䉌ᄢ䈐䈒ᄌൻ䈜䉎น⢻ᕈ䉅⠨䈋䉌䉏䉎䇯㜞ㅦၞ䈮䈍䈔䉎ᑧᕈ⎕უ᜼േ䈱䊚䉪䊨⊛䊶䊙䉪䊨⊛䈭⺞ᩏ䈏ᔅⷐ䈪䈅䉎䇯㩷㩷㩷㧙㧙(a) quasi-static(b) V=0.7m/s(c) V=3.0m/s(d) V=4.2m/s

Fig.10 SEM fractography of the fractured surfaces.

(a) quasi-static(b) V=0.7m/s(c) V=3.0m/s㩷(d) V=4.2m/s

Fig.11 3-D images of the fractured surfaces.
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