ᒝ䈵䈝䉂ടᎿ䈮䉋䉍૞⵾䈚䈢䊅䊉䊶䉰䊑䊚䉪䊨䊮⚿᥏☸䊋䊦䉪 㪠㪝 ㍑䈱∋ഭ․ᕈ㩷⎇ⓥઍ⴫⠪ ⼾ᯅᛛⴚ⑼ቇᄢቇ ಎᢎ᝼ ᚭ㜞⟵৻౒ห⎇ⓥ⠪ ⼾ᯅᛛⴚ⑼ቇᄢቇ ᢎ᝼ ᪢ᧄታ䋱䋮㩷 ✜⸒⚿᥏☸ᓸ⚦ൻ䈮䉋䉎ജቇ․ᕈะ਄䈲䇮ว㊄ర⚛ᷝട╬䈱ᣇᴺ䈮Ყ䈼䈩䈠䈱⒟ᐲ䈏ᄢ䈐䈒䇮Ⅳ Ⴚ ໧ 㗴 䉇 ర ⚛ ᚢ ⇛ 䈱 ⷰ ὐ 䈎 䉌 䉅 ㊀ ⷐ 䈪 䈅 䉎 䇯 ᒝ 䈵 䈝 䉂 ട Ꮏ 䋨 Severe Plastic
Deformation: SPD䋩䈲䇮ઁ䈱⚿᥏☸ᓸ⚦ൻᴺ䈫Ყ䈼䈩᧚ᢱ䈱⒳㘃䈱೙⚂䈏ዊ䈘䈒䇮◲ଢ䈪䇮䉁䈢䇮ㄭᐕ HPT[1], ECAP[1,2], ARB[3]╬䈱ᒻ⁁ਇᄌടᎿ䈏㐿⊒䈘䉏䈢䈖䈫䈪Ყセ⊛ᄢ䈐䈭䊅䊉䊶䉰䊑䊚䉪䊨䊮⚿᥏☸䊋䊦䉪᧚ᢱ䉕૞⵾䈜䉎䈖䈫䈏น⢻䈫䈭䈦䈢䇯䈠䉏䉌䈱ടᎿᣇᴺ䈱ਛ䈪䇮HPT䋨High-Pressure Torsion䋩䈲ૐ᷷䈪⪺䈚䈒ᄢ䈐䈭ᱡ㊂䊶ᱡ൨㈩䉕⹜ᢱ䈮ઃਈ䈜䉎䈖䈫䈏䈪䈐䉎䈢䉄䇮⚿᥏☸ᓸ⚦ൻ䈮᦭೑䈪䈅䉎[4-6]䇯䊅䊉䊶䉰䊑䊚䉪䊨䊮⚿᥏☸䊋䊦䉪᧚䈏૞⵾䈪䈐䉎䉋䈉䈮䈭䈦䈢䈖䈫䈪䇮䈠䈱ജቇ․ᕈ䈏᣿䉌䈎䈮䈭䉍䈧䈧䈅䉎䇯䈠䈱ਛ䈱⥝๧ᷓ䈇․ᕈ䈱৻䈧䈮䇮㜞ᒝᐲ䈫㜞ᑧᕈ䈱ਔ┙䈏᜼䈕䉌䉏䉎䇯৻⥸⊛䈮㊄ዻ᧚ᢱ䈲ᒝᐲ䈏㜞䈇䈫ᑧᕈ䈲ૐਅ䈜䉎䇯䈚䈎䈚䈭䈏䉌䇮ᒝ䈵䈝䉂ടᎿ䈪૞⵾䈚䈢䊅䊉䊶䉰䊑䊚䉪䊨䊮⚿᥏☸᧚ᢱ䈪䈲䇮ㅢᏱ᧚䈪䈲ᓧ䉌䉏䈭䈇㜞ᒝᐲ䊶㜞ᑧᕈ䉕␜䈜䈖䈫䈏ႎ๔䈘䉏䈩䈇䉎[7-10]䇯䉁䈢䇮䈠䈱䉋䈉䈭ఝ䉏䈢ᒁᒛ․ᕈ䉕᦭䈜䉎䈖䈫䈎䉌䇮∋ഭ․ᕈ䈱ะ਄䉅ႎ๔䈘䉏䈩䈇䉎䈏[10,11]䇮ᧂ䈣චಽ䈮⺞ᩏ䈘䉏䈩䈇䈭䈇䈱䈏⃻⁁䈪䈅䉎䇯ᧄ⎇ⓥ䈪䈲䇮HPT ടᎿ䈮䉋䉍૞⵾䈚䈢䉰䊑䊚䉪䊨䊮⚿᥏☸䊋䊦䉪 IF ㍑䈱ᒁᒛ․ᕈ䈫∋ഭ․ᕈ䉕⺞ᩏ䈚䈢[12]䇯
䋲䋮㩷 ታ㛎ᣇᴺ
ଏ⹜᧚䈫䈚䈩䇮IF ㍑䋨11C, <30Si, <30Mn, <20P, <3S, <2B, 8N, 14O, 300Al, <20Ti,<30Cr, <30Cu, mass ppm䋩䉕⚐ Ar 㔓࿐᳇䈪 1000 㷄, 3.6 ks 䈱ဋ⾰ൻಣℂ䉕ᣉ䈚䈩↪䈇䈢䇯⋥ᓘ 10 mm, ෘ䈘 0.85 mm 䈱౞᧼䉕䇮Fig. 1 䈮␜䈜䉋䈉䈮䇮⋥ᓘ 10 mm, ᷓ䈘 0.25mm 䈱┄䉂䈱䈅䉎 2 䈧䈱ᴦౕ䈪᜽䉂䇮࿶❗ᔕജ 5 GPa, ࿁ォㅦᐲ 0.2 rpm, ቶ᷷䈱᧦ઙ䈪
HPT ടᎿ䈚䈢䇯(a)Thermocouple(b)

Load(K-type)

Upper anvil

LubricantLower anvil

SpecimenRotationFig. 11mm

LoadInitial shape:
I10mm㬍t0.85 mm(a) Schematic illustration of a set up for HPT-straining and (b)overview of anvil.

㧙㧙

HPT ടᎿ䈮䈍䈔䉎⋧ᒰᱡ㊂䈲ᰴᑼ䉋䉍᳞䉄䉌䉏䉎䇯Heq = J / 㺕3, J = 2 Sҏ 䍃 NHPT 䍃 r / t
J: 䈞䉖ᢿᱡ, NHPT: ࿁ォ࿁ᢙ, r: ౞᧼ਛᔃ䈎䉌䈱〒㔌, t: ⹜ᢱෘ䈘䋨0.6 mm䋩
౞᧼ਛᔃ䈱⴫㕙䈎䉌 1 mm 㔌䉏䈢ᴦౕ䈱᷷ᐲ䉕᷹ቯ䈚䇮⹜ᢱ᷷ᐲ䈫䈚䈢䇯ടᎿ⊒ᾲ䈮䉋䉍⹜ᢱ᷷ᐲ䈲਄᣹䈜䉎䉅䈱䈱䇮40 㷄⒟ᐲ䈪㘻๺䈚䈢䇯ᴦౕ䈱៺⠻䉕㒐䈓⋡⊛䈪䇮⹜ᢱ䉁䉒䉍䈱਄ਅ䈱ᴦౕធ⸅ㇱ䈮䇮MoS2 ẢṖ䉫䊥䊷䉴䉕ႣᏓ䈚䈢䇯䉁䈢䇮⹜ᢱ䋯ᴦౕ㑆䈱䈜䈼䉍䉕ᛥ೙䈜䉎䈢䉄䇮ᴦౕ䈱┄䉂ㇱ⴫㕙䈮ಳಲ䉕⸳䈔䈢䇯ടᎿਛ䈮䈜䈼䉍䈏↢䈛䈢႐ว䇮Fig. 2 䈮␜䈜䉋䈉䈮䇮᣿䉌䈎䈭⹜ᢱ⴫㕙ᒻᘒ䈱ᄌൻ䈏↢䈛䉎䇯⹜ᢱ䈲䇮ടᎿਛ਄ਅ䈱ᴦౕ䈱㑆䈎䉌ᵹ䉏಴䉎䈢䉄䇮ෘ䈘䈲 0.6 mm ⒟ᐲ䉁䈪ᷫዋ䈚䈢䇯Ყセ᧚䈫䈚䈩䇮NHPT = 5 䈱 HPT ടᎿᓟ 200 㷄, 3.6 ks 䈱ᾲಣℂ䉕ᣉ䈚䈢⹜ᢱ䋨NHPT=5+A ᧚䋩䈫䇮90 %಄㑆࿶ᑧ䈚䈢⹜ᢱ䋨90%CR ᧚䋩䉕↪ᗧ䈚䈢䇯NHPT = 5+A ᧚䈱䊎䉾䉦䊷䉴⎬䈘䈲 NHPT = 5 ᧚䈫ᄌ䉒䉌䈝 Hv 3.6 ks 䈪䈅䉍䇮200 㷄એ਄䈱᷷ᐲ䈪ᾲಣℂ䈜䉎䈫⪺䈚䈒エൻ䈚䈢[7]䇯90%CR ᧚䈲䇮1 䊌䉴ᒰ䈢䉍࿶ൻ₸ 10 ~ 20 %䈪✚࿶ਅ₸ 90 %䉁䈪ቶ᷷䈪࿶ᑧ䈚䈢䇯∋ഭ⹜㛎䈮䈍䈔䉎⹜ᢱ⴫㕙☻䈘䈱ᓇ㗀䉕⺞䈼䉎䈢䉄䇮ᯏ᪾⎇⏴䋨#4000 䉣䊜䊥䊷⚕䋩䉁䈢䈲㔚⸃⎇⏴䋨10 vol% HClO4 + 90 vol% C2H5OH ṁᶧ䋩䈮䈩ᦨ⚳઀਄䈕䈚䈢 2 ⒳㘃䈱⹜ᢱ䉕૞⵾䈚䈢䇯ട Ꮏ ᓟ 䈱 ⹜ ᢱ 䈮 䈧 䈇 䈩 䇮 FESEM-EBSP 䋨 JEOL JSM-6500F - OXFORD INCA
Crystal, HKL CHANNEL5 software䋩, TEM䋨HITACHI H-800䋩, ᒁᒛ䊶∋ഭ⹜㛎䋨SHIMADZU EHF-LV020k1䋩, 䊎䉾䉦䊷䉴⎬䈘⹜㛎䋨SHIMADZU HMV-1ADW䋩䉕ⴕ䈦䈢䇯ᒁᒛ⹜㛎䈲䇮ෘ䈘 0.5 mm 䈱䊚䊆䉼䊠䉝⹜㛎s-1 䈪 ⴕ 䈦 䈢 䇯 ᱡ ㊂ H 䈲 䇮 ⹜ 㛎

䋨Fig. 3a䋩䉕↪䈇䈩䇮ೋᦼᱡㅦᐲ 1㬍103⢋ ㇱ 䈱 㑆 㓒 L 䋨 Fig. 3b 䋩 䉕 CCD 䉦 䊜 䊤 䋨 KEYENCECV-200M䋩䈪᷹ቯ䈚䈢䇯CCD 䉦䊜䊤䈱ಽ⸃⢻䈲⚂ 2 Pm 䈪䈅䉎䇯∋ഭ⹜㛎䈲䇮ෘ䈘 0.5 mm 䈱䊚䊆䉼䊠䉝⹜㛎䋨Fig. 4䋩䉕↪䈇䈩䇮ᔕജᲧ R = 0.1, 䉰䉟䊮ᵄᒻ, ๟ᵄᢙ 20 Hz 䈪ㇱಽ䉍ᒁᒛ∋ഭ⹜㛎䉕ⴕ䈦䈢䇯䉁䈢䇮∋ഭ⹜㛎ᓟ䈱⹜㛎䈮䈍䈇䈩䇮⎕ᢿ㕙䈎䉌 0.5 mm 㔌䉏䈢㗔ၞ䈱䊎䉾䉦䊷䉴⎬䈘䉕 0.98 N, 10 s 䈱᧦ઙ䈪᷹ቯ䈚䈢䇯(a)(b)2mm

Fig. 2

Surface morphologies of disks (a) without / (b) with slip between

disk and anvil during HPT-straining. (a) 1050 Al, HPT condition: 5 GPa, 5rpm, NHPT = 1, R.T. and (b) Fe - 3.3 mass%Si steel, 3 GPa, 1 rpm, NHPT = 10,R.T.

㧙㧙ᝄ1.8(b) Upper

3.0die

R0.2
1.0

7.4

3.0

1.5Load1.0(a)1.4L

Unit: mmFig. 3Tensile
specimen
Lower
Loaddie5.0

Schematic illustrations of (a) tensile specimen shape and (b) a setup for tensile test. Miniature tensile specimen was cut from the off-center
position of HPT-processed disk.
1.5

1.0
4.0

1.4

9.4

R1.0
R0.7
2.8

Unit: mmFig. 46.0

Schematic illustration of fatigue specimen shape. Miniature fatigue

specimen was cut from the off-center position of HPT-processed disk.

䋳䋮㩷 ታ㛎⚿ᨐ䈍䉋䈶⠨ኤFig. 5 䈮䇮NHPT = 5 ᧚䈱 FESEM-EBSP ⸃ᨆ⚿ᨐ䉕␜䈜䇯ⷰኤ႐ᚲ䈲䇮౞᧼ਛᔃ䈎䉌 r =1.5mm䋨Heq = 45䋩䈱㗔ၞ䈪䈅䉎䇯⚿᥏ᣇ૏ಽᏓ࿑䉋䉍䇮᏷ 300 nm, 㐳䈘 600 nm ⒟ᐲ䈱િ㐳☸䈏ᒻᚑ䈚䈩䈇䉎䈖䈫䈏ಽ䈎䉎䇯䉁䈢䇮ዪᚲᣇ૏ᏅಽᏓ䉋䉍䇮☸ౝ䈱ォ૏䋨ᐞ૗ቇ⊛䈮ᔅⷐ䈭ォ૏䋨GN ォ૏䋩䋩䈱⫾Ⓧ䈱⒟ᐲ䉕⍮䉎䈖䈫䈏䈪䈐䉎䇯Fig. 5 ਛ䈱⚿᥏☸ A, B 䈲䇮☸ౝ䈮ᣇ૏Ꮕ䈏ᱴ䈬䈭䈇䇯䈖䈱䉋䈉䈭ૐォ૏ኒᐲ䈭⚿᥏☸䈲 TEM ⷰኤ䈮䈍䈇䈩䉅ⷰኤ䈘䉏䈢䋨Fig. 6a䋩䇯
HPT ടᎿ䈮䉋䉍ㅪ⛯ౣ⚿᥏䈏↢䈛䈢䈢䉄䈮ᒻᚑ䈚䈢䈫⠨䈋䉌䉏䉎䇯䉁䈢䇮 NHPT = 5 ᧚䉕
200 㷄, 3.6 ks 䈪ᾲಣℂ䈚䈢 NHPT = 5+A ᧚䈱 TEM ⷰኤ⚿ᨐ䉕 Fig. 6b 䈮␜䈜䇯NHPT = 5᧚䈫Ყセ䈚䈩ォ૏ኒᐲ䈲ᷫዋ䈚䈩䈇䉎䈏䇮⚿᥏☸ᓘ䈱ᄢ䈐䈭ᄌൻ䈲⹺䉄䉌䉏䈭䈇䇯
Fig. 7 䈮⒳䇱䈱࿁ォ࿁ᢙ䈪 HPT ടᎿ䈚䈢⹜ᢱ䈱ᒁᒛ․ᕈ䉕␜䈜䇯࿁ォ࿁ᢙ䋨ᱡ㊂䋩䈱Ⴧട䈮઻䈦䈩ᒝᐲ䈏Ⴧട䈚䇮NHPT = 5 એ਄䈱 HPT ടᎿ᧚䈪䈲䇮ᒁᒛᒝᐲ䈏 1.9 GPa 䈮㆐䈚䈢䇯ᒁᒛᒝᐲ TS 䈫䊎䉾䉦䊷䉴⎬䈘 Hv 䈲᭎䈰 TS = Hv/3 䈱㑐ଥ䈏ᚑ䉍┙䈧䈏䇮NHPT = 5 ᧚䇮

NHPT = 10 ᧚䈪䈲䈠䈱㑐ଥ䈎䉌ㅺ⣕䈜䉎㜞䈇ᒁᒛᒝᐲ䉕␜䈜䇯䈖䈱ℂ↱䈮䈧䈇䈩䈲ᧂ䈣᣿䉌䈎䈮䈭䈦䈩䈇䈭䈇䇯ᑧᕈ䈲䇮NHPT = 5 䉁䈪䈱 HPT ടᎿ䈪䈲䇮ᒝᐲ䈱Ⴧട䈮઻䈦䈩ᓥ᧪䈱ടᎿ᧚䈫ห᭽䈮ૐਅ䈚䈢䇯䈚䈎䈚䈭䈏䉌䇮䈘䉌䈮ടᎿ䈚䈢 NHPT = 10 ᧚䈪䈲䇮ᒁᒛᒝᐲ䈱ૐਅ䈭㧙㧙

Orientation map

Local misorientation map

AB>15㫦㪔㪈㪇㪇㩷 㱘㫄 㪒㩷㪞㪙㩷㪒㩷 㪪㫋㪼㫇㪔㪈㩷䍓㫄 㪒㩷㪞㫉㫀㪻㪉㪌㪍㫏㪈㪐㪉

Subgrain angle

0㫦

1Pm

3㫦

EBSD maps at the region of r = 1.5 mm after HPT-straining forFig. 5

NHPT = 5 (Heq = 45).
(a) NHPT = 5Fig. 6(b) NHPT = 5+A

500nm

TEM micrographs at the region of r = 3.2 mm after (a)HPT-straining for NHPT = 5 (Heq = 97) and (b) subsequent annealing at200 㷄 for 3.6 ks.
䈒ᑧᕈ䈏Ⴧട䈚䈢䇯䈖䉏䈲 HPT ടᎿ䈮䉋䉍ᒻᚑ䈜䉎ㅪ⛯ౣ⚿᥏☸䈏䇮ᔕജ㓸ਛ䉕✭๺䈚䇮ᄌᒻ䉕ᜂ䈦䈢䈢䉄䈪䈅䉎䈫⠨䈋䉌䉏䉎䇯ᾲಣℂ䈮䉋䉍ㅪ⛯ౣ⚿᥏☸䉕Ⴧട䈘䈞䈢 NHPT = 5+A ᧚䈮䈍䈇䈩䉅ᒁᒛᒝᐲ䈱ૐਅ䈭䈒ᑧᕈ䈱ะ਄䈏⏕⹺䈪䈐䈢䈖䈫䈎䉌䋨Fig. 7b䋩䇮ૐォ૏ኒᐲ䈱⚿᥏☸䈏ᑧᕈ䈱ะ਄䈮ነਈ䈚䈩䈇䉎䈖䈫䈏᣿䉌䈎䈪䈅䉎䇯䉁䈢䇮ォ૏ኒᐲ䉕ᄌൻ䈘䈞䈢 NHPT = 5
᧚, NHPT = 10 ᧚, NHPT = 5+A ᧚䈱ᒝᐲ䈏ห⒟ᐲ䈪䈅䈦䈢䈖䈫䈎䉌䇮䈖䉏䉌䈱ᒝᐲ䈲⚿᥏☸ᓸ⚦ൻ䈮ਥ䈮⿠࿃䈜䉎䈖䈫䈏ಽ䈎䉎䇯NHPT = 5+A ᧚䈮䈍䈇䈩䈲㒠ફ⃻⽎䈏⹺䉄䉌䉏䈢䋨Fig. 7b䋩䇯䈖䈱䉋䈉䈭㒠ફ⃻⽎䈲ᒝ䈵䈝䉂ടᎿ䈍䉋䈶䈠䈱ᓟᾲಣℂ䈚䈢䇮৻⥸䈮㒠ફ⃻⽎䉕␜䈘䈭䈇䇮⚐ Al 䈪䉅ႎ๔䈘䉏䈩䈇䉎[13,14]䇯䈖䉏䈲ᾲಣℂ䈮䉋䉍⚿᥏☸⇇䈏቟ቯൻ䈚䇮ォ૏䈏⊒↢䈚㔍䈒䈭䈦䈢䈖䈫䈮⿠࿃䈜䉎䈫⠨䈋䉌䉏䉎[14]䇯৻ᣇ䈪ᒝ䈵䈝䉂ടᎿ᧚䈪䈲䇮☸⇇䈏㜞䈇ේሶ䈱⒖േᐲ䉕䉅䈧䈢䉄䇮㒠ફ⃻⽎䈲⹺䉄䉌䉏䈭䈇䇯ਇဋ৻ᄌᒻ䈏ᄢ䈐䈒↢䈛䉎⹜ᢱ䈪䈲䇮䊚䊆䉼䊠䉝ᒁᒛ⹜㛎䉵䈱⹜㛎䉕૶↪䈜䉎䈫䇮ᑧᕈ䈏ㅢᏱ䉰䉟䈮䉋䉎⚿ᨐ䈮Ყ䈼䈩䉇䉇ᄢ䈐䈒䈭䉎[15]䇯NHPT = 10 ᧚䈱ᒁᒛᒝᐲ䈍䉋䈶િ䈶䈲䇮หᒻ⁁䈱⹜㛎䉕↪䈇䈢䊙䊦䉣䊷䉳䊮䉫㍑䈱⹜㛎䈮䈍䈇䈩䇮䈾䈿ห╬䈱ᒁᒛ․ᕈ䉕␜䈚䈢

[16]䇯ᒝ䈵䈝䉂ടᎿ䈜䉎䈖䈫䈪 IF ㍑䈏䊙䊦䉣䊷䉳䊮䉫㍑䈮඘ᢜ䈜䉎ᒁᒛ․ᕈ䉕␜䈚䈢䈖䈫䈲㛳䈐䈮୯䈜䉎䇯

㧙㧙

(a)

(b)

2000

2000

1500

Engineering stress, V / MPa

Engineering stress, V / MPa

NHPT=5+A (Heq=45, Hv3.6GPa)
NHPT=10(Heq=91, Hv3.6GPa)
NHPT=5 (Heq=45, Hv3.6GPa)

1000

NHPT=2 (Heq=18)

500090%CR(Heq=2.7, Hv2.1GPa)

NHPT=1(Heq=9, Hv2.8~3.2GPa)

1500

NHPT=5 (Heq=45, Hv3.6GPa)

1000

Fig. 7

0.1

0.2
0.3
0.4
Engineering strain, H

0.5

NHPT=2 (Heq=18)

500

As-prepared (Hv0.6GPa)

0NHPT=10(Heq=91, Hv3.6GPa)

0.6090%CR(Heq=2.7, Hv2.1GPa)

NHPT=1(Heq=9, Hv2.8~3.2GPa)

As-prepared (Hv0.6GPa)

00.1

0.2
0.3
0.4
Engineering strain, H

0.5

0.6

Engineering tensile stress-strain curves of (a) HPT-processedspecimens after various turns and (b) subsequent annealing at 200 㷄 for
3.6 ks. Vickers microhardness, Hv, was measured under an applied load of
4.9 N for 10 s.
Fig. 8 䈮∋ഭ․ᕈ䈮෸䈿䈜⴫㕙☻䈘䈱ᓇ㗀䉕␜䈜䇯90%CR ᧚䈲䇮ᯏ᪾⎇⏴, 㔚⸃⎇⏴䈱೎䈮䉋䉌䈝䇮ห᭽䈭∋ഭ․ᕈ䉕␜䈚䈢䇯৻ᣇ䇮NHPT = 5 ᧚䈪䈲䇮㔚⸃⎇⏴䉕ᣉ䈜䈖䈫䈪䇮⪺䈚䈇∋ഭ․ᕈ䈱ᡷༀ䈏⹺䉄䉌䉏䈢䇯
Fig. 9 䈮䇮㔚⸃⎇⏴䈮䈩ᦨ⚳઀਄䈕䉕ᣉ䈚䈢ฦ⒳⹜ᢱ䈱∋ഭ․ᕈ䉕␜䈜䇯NHPT = 5, 10,5+A ᧚䈱․ᕈ䈲ห⒟ᐲ䈪䈅䉍䇮ᑧᕈ䈱㆑䈇䈮䉋䉎∋ഭ․ᕈ䈱ᄌൻ䈲⹺䉄䉌䉏䈭䈎䈦䈢䇯ૐ䉰䉟䉪䊦㗔ၞ䈪䈲䇮90%CR ᧚䈮Ყ䈼䈩ઁ䈱⹜ᢱ䈲 2 ୚⒟ᐲ䈱∋ഭᒝᐲ䈱਄᣹䈏⹺䉄䉌䉏䈢䇯䈚䈎䈚䈭䈏䉌䇮㜞䉰䉟䉪䊦㗔ၞ䈪䈲䇮䈇䈝䉏䈱⹜ᢱ䈱․ᕈ䉅ᄢ䈐䈭㆑䈇䈲⹺䉄䉌䉏䈭䈎䈦䈢䇯䈖䈱ℂ↱䈫䈚䈩䇮ᒝ䈵䈝䉂ടᎿ䈚䈢䉰䊑䊚䉪䊨䊮⚿᥏☸᧚ᢱ䈱ಾᰳᗵฃᕈ䈏㜞䈇䈖䈫䈏⠨䈋䉌䉏䉎[11]䇯䉁䈢䇮➅㄰䈚ᄌᒻ䈮䉋䉎エൻ䈱ᓇ㗀䉅⠨䈋䉌䉏䉎[17]䇯䈚䈎䈚䈭䈏䉌䇮NHPT = 5, 10,5+A ᧚䈪䈲∋ഭ⹜㛎೨ᓟ䈪ᄢ䈐䈭⎬䈘ᄌൻ䈲⹺䉄䉌䉏䈭䈎䈦䈢䇯䈖䉏䈲䇮ᒁᒛ⹜㛎䈱⚿ᨐ䈎䉌᣿䉌䈎䈭䉋䈉䈮䇮NHPT = 5, 10, 5+A ᧚䈲⚿᥏☸ᓸ⚦ൻᒝൻ䈏ਥ䈪䈅䉍䇮➅㄰䈚ᄌᒻ䈮䉋䉎ォ૏䈱ᶖṌ䋨࿁ᓳ䋩䈏ᒝᐲ䈮ᄢ䈐䈒ᓇ㗀䈚䈭䈇䈢䉄䈪䈅䉎䇯৻ᣇ䈪䇮90%CR ᧚䈪䈲䇮∋ഭ⹜
㛎䋨Nf = 1.6㬍105䋩ᓟ 81 %䈱⎬䈘䉁䈪エൻ䈚䈢䇯䉁䈢䇮Fig. 9 䈮䈍䈇䈩䇮NHPT = 10 ᧚䈱∋ഭ․ᕈ䈏 NHPT = 5, 5+A 䈮Ყ䈼䈩䈳䉌䈧䈇䈩䈇䉎䈖䈫䈏ಽ䈎䉎䇯Fig. 10 䈮␜䈜䉋䈉䈮䇮NHPT = 10 ᧚䈱ᦨ⚳∋ഭ⎕㕙䈮䈍䈇䈩䈻䈐㐿㕙䈏ㇱಽ⊛䈮ⷰኤ䈘䉏䈢䇯90%CR ᧚, NHPT = 5, 5+A ᧚䈪䈲䇮ᑧᕈ⊛䈭⎕უ䉕␜䈜䊂䉞䊮䊒䊦䈱䉂䈏ⷰኤ䈘䉏䈢䇯NHPT = 10 ᧚䈪䈲䇮⹜ᢱౝㇱ䈮⣀ᕈ⊛䈭㗔ၞ䈏ሽ࿷䈜䉎䈢䉄䈮∋ഭ․ᕈ䈏䈳䉌䈧䈇䈢䈫⠨䈋䉌䉏䉎䇯䈖䈱䉋䈉䈭䈻䈐㐿㕙䈱ᒻᚑ䈲䇮HPT ടᎿਛ䈱ਇ⚐‛ర⚛䈱ಝ㓸䈮⿠࿃䈜䉎䈫⠨䈋䉌䉏䉎䇯㧙㧙

1600

Maximum stress, V / MPa

1400
1200
1000
800
600
40090%CR EP
90%CR #4000
NHPT=5 EP
NHPT=5 #4000

2000102103104

105106107

108

Cycles to failure, NfFig. 8

Effect of surface roughness on the fatigue property in theHPT-processed (NHPT = 5) and the cold-rolled (90% reduction) specimens.
EP: electrical polishing, #4000: mechanical polishing by using emery paperwith #4000.

1600

Maximum stress, V / MPa

1400
1200
1000
800
600
40090%CR
NHPT=5NHPT=10NHPT=5+A2000102103104105106107

108Cycles to failure, NfFig. 9S-N diagram of the electrical polished specimens after cold-rolling,HPT-straining and annealing. Arrows indicate that no fracture has been
observed at a given stress and number of cycles.

㧙㧙

90%CR
V=550MPa, Nf=1.63㬍105

NHPT = 5
V=1000MPa, Nf=2.66㬍103

NHPT = 5+A
V=600MPa, Nf=2.02㬍106

NHPT = 10
V=700MPa, Nf=1.12㬍105

1PmFig. 10

Morphologies of fracture surface at the final fracture areas afterfatigue tests.

䋴䋮㩷 䉁䈫䉄(1)㩷 HPT ടᎿ䈮䉋䉍䇮᏷ 300 nm, 㐳䈘 600 nm ⒟ᐲ䈱િ㐳☸䈎䉌䈭䉎䉰䊑䊚䉪䊨䊮⚿᥏☸᧚ᢱ䈏૞⵾䈪䈐䈢䇯䈠䈱䊎䉾䉦䊷䉴⎬䈘䈲 Hv 3.6 GPa 䈪䈅䈦䈢䇯(2)㩷 NHPT = > 5䋨Heq = > 45䋩䈱 HPT ടᎿ᧚䈪䈲䇮ᒁᒛᒝᐲ䈏 1.9 GPa 䈮㆐䈚䈢䇯NHPT = > 5
䋨Heq = > 45䋩䈱 HPT ടᎿ䈫ᾲಣℂ䈮䉋䉍䇮ᒁᒛᒝᐲ䈱ૐਅ䈭䈒ᑧᕈ䈱ะ਄䈏⹺䉄䉌䉏䈢䇯䈠䉏䉌䈱୯䈲䊙䊦䉣䊷䉳䊮䉫㍑䈮඘ᢜ䈜䉎䇯(3)㩷 HPT ടᎿ䈮䉋䉍ᒁᒛᒝᐲ䈱ૐਅ䈭䈒ᑧᕈ䈏ᡷༀ䈚䈢ℂ↱䈲䇮HPT ടᎿ䉁䈢䈲ᾲಣℂ䈮䉋䉍ㅪ⛯ౣ⚿᥏䈏↢䈛䇮㜞ⷺ☸⇇䉕䉅䈧ૐォ૏ኒᐲ䈭⚿᥏☸䈏ᒻᚑ䈚䈢䈖䈫䈪䇮ォ૏䈱࿁ᓳ䈏ଦㅴ䈘䉏䇮䉁䈢䇮ᔕജ㓸ਛ䈏✭๺䈘䉏䈢䈢䉄䈪䈅䉎䈫⠨䈋䉌䉏䉎䇯(4)㩷 ⴫㕙☻䈘䈱∋ഭ․ᕈ䈻䈱ᓇ㗀䈲 90%CR ᧚䈪䈲ᱴ䈬䈭䈎䈦䈢䈏䇮NHPT = 5 ᧚䈮䈍䈇䈩䈲⴫㕙☻䈘䈱ᡷༀ䈮䉋䉍∋ഭ․ᕈ䈏⪺䈚䈒ะ਄䈚䈢䇯(5)㩷 ૐ䉰䉟䉪䊦㗔ၞ䈪䈲䇮90%CR ᧚䈮Ყ䈼䈩 NHPT = 5, 10, 5+A ᧚䈲 2 ୚⒟ᐲ䈱∋ഭᒝᐲ䈱਄᣹䈏⹺䉄䉌䉏䈢䇯䈚䈎䈚䈭䈏䉌䇮㜞䉰䉟䉪䊦㗔ၞ䈪䈲䇮䈇䈝䉏䈱⹜ᢱ䉅ᄢ䈐䈭㆑䈇䈲⹺䉄䉌䉏䈭䈎䈦䈢䇯䈖䉏䈲䇮ᒝ䈵䈝䉂ടᎿ䈚䈢䉰䊑䊚䉪䊨䊮⚿᥏☸᧚ᢱ䈱ಾᰳᗵฃᕈ䈏㜞䈇䈖䈫䈏ේ࿃䈫⠨䈋䉌䉏䉎䇯㧙㧙⻢ㄉᧄ⎇ⓥ䈲䇮JFE䋲䋱਎♿⽷࿅ᛛⴚ⎇ⓥഥᚑ䈍䉋䈶⑼ቇ⎇ⓥ⾌⵬ഥ㊄䉋䉍េഥ䉕ฃ䈔䈩ታᣉ䈚䉁䈚䈢䇯㑐ଥฦ૏䈮ᷓ䈒ᗵ⻢↳䈚਄䈕䉁䈜䇯ෳ⠨ᢥ₂[1]

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