放射光CTによる鋳造アルミニウム合金の内在欠陥調査と破壊力学的評価: 沖縄地域学リポジトリ

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Author(s)

政木, 清孝; 佐野, 雄二

Citation

沖縄工業高等専門学校紀要 = Bulletin of Okinawa National

_{College of Technology(7): 1-10}

Issue Date

2013-03

URL

http://hdl.handle.net/20.500.12001/18694

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1 ؗථࢥުࣞ൝୺࿝ڠࢷܮါȁల7 ࣢ȇp.1-10, 2013 ISSN：1881-722X

ᨺᑕග &7 ࡟ࡼࡿ㗪㐀࢔࣑ࣝࢽ࣒࢘ྜ㔠ࡢෆᅾḞ㝗ㄪᰝ࡜◚ቯຊᏛⓗホ౯

㸨_ᨻᮌΎᏕ㸯_{㸪బ㔝㞝஧}㸰㸯_{Ἀ⦖ᕤᴗ㧗➼ᑓ㛛Ꮫᰯ ᶵᲔࢩࢫࢸ࣒ᕤᏛ⛉㸪}㸰_{ᰴᘧ఍♫ ᮾⰪ} せ᪨ 㗪㐀࢔࣑ࣝࢽ࣒࢘ྜ㔠ࡢ⑂ປ◚ቯ≉ᛶࡣࠊ㗪㐀᫬࡟Ⓨ⏕ࡋࡓᮦᩱෆ㒊ࡢ㗪㐀Ḟ㝗ࡢᩘࡸ኱ࡁࡉ࡟ࡼࡿ ࡜ࡇࢁࡀ኱ࡁ࠸ࠋࡑࡢࡓࡵ㒊ᮦෆ㒊ࡢ㗪㐀Ḟ㝗ࡢ㠀◚ቯ᳨ᰝ࡜ホ౯ࡀ㔜せ࡛࠶ࡿࡀࠊᮏ◊✲࡛ࡣᨺᑕග ࢆ฼⏝ࡋࡓ᩿ᒙ᧜ᙳᢏ⾡㸦CT㸧࡟ὀ┠ࡋࡓࠋᨺᑕග CT ࡟ࡼࡗ࡚ヨ㦂∦ෆ㒊ࡢḞ㝗ㄪᰝ࡜◚ቯຊᏛⓗᡭ ἲ࡟ᇶ࡙ࡃḞ㝗ࡢホ౯ࢆ⾜࠸ࠊ㗪㐀Ḟ㝗ࡀ⑂ປ≉ᛶ࡟ཬࡰࡍᙳ㡪ࢆᐃ㔞ⓗ࡟ண ࡋࡓࠋෆᅾḞ㝗ࢆㄪᰝ ࡋࡓヨ㦂∦࡟ࡘ࠸࡚⑂ປヨ㦂ࢆᐇ᪋ࡋࡓ࡜ࡇࢁࠊෆᅾࡍࡿ㗪㐀Ḟ㝗ࡢᙧ≧࣭ศᕸ≧ែ࡟ࡼࡗ࡚ࡣࠊ᳨ฟ ࡉࢀࡓḞ㝗ࡢⲴ㔜㍈᪉ྥ࡬ࡢᢞᙳ㠃✚࠿ࡽᛂຊᣑ኱ಀᩘࢆ⟬ฟࡍࡿ୍⯡ⓗ࡞᪉ἲ࡟ࡼࡿホ౯ࡀ㐺ษ࡛ ࡞࠸ࡇ࡜ࡀ᫂ࡽ࠿࡜࡞ࡗࡓࠋࡓࡔࡋࠊᏳ඲ഃ࡬ࡢホ౯࡜࡞ࡿࡓࡵࠊᐇ⏝ⓗ࡟ࡣၥ㢟࡞࠸ࡇ࡜ࢆ♧ࡋࡓࠋ ࣮࣮࢟࣡ࢻ㸸ᨺᑕගࠊ᩿ᒙ᧜ᙳᢏ⾡ࠊ㗪㐀࢔࣑ࣝࢽ࣒࢘ࠊ㗪㐀Ḟ㝗ࠊᛂຊᣑ኱ಀᩘ 㸯㸬⥴ゝ ᵓ㐀≀ࡢᦆയࡣ⑂ປ࡟ࡼࡿࡇ࡜ࡀከࡃࠊ࡞࠿࡛ࡶ⾲㠃࠿ࡽ◚ቯࡍࡿሙྜࡀ኱༙ࢆ༨ࡵࡿࠋࡋ࠿ࡋࠊ㍺㏦ᶵჾ࡞࡝࡟ከ⏝ࡉࢀ࡚࠸ࡿ࢔࣑ࣝࢽ࣒࢘ྜ㔠〇ࡢ㗪㐀㒊ရࡸࢲ࢖࢝ࢫࢺ㒊ရࡣࠊᮦᩱෆ㒊࡟ከࡃࡢ㗪㐀Ḟ㝗ࢆྵࡴࡓࡵࠊᮦᩱෆ㒊ࡢ㗪㐀Ḟ㝗ࢆ㉳Ⅼ࡜ࡋ࡚⑂ປ◚ቯࡍࡿྍ⬟ᛶࡀ࠶ࡿࠋࡇࡢࡼ࠺࡞ᮦᩱෆ㒊 ࡢ㗪㐀Ḟ㝗ࡀࡁ⿣ࡢⓎ⏕㉳Ⅼ࡜࡞ࡿሙྜ࡟ࡣ⾲㠃࠿ࡽࡁ⿣ࡢⓎ⏕ࡸ㐍ᒎࢆ᳨ฟ࡛ࡁ࡞࠸ࡓࡵࠊ㒊ᮦࡢ✺ ↛◚ቯࢆᘬࡁ㉳ࡇࡍྍ⬟ᛶࡀ࠶ࡾࠊ኱ࡁ࡞஦ᨾ࡬࡜⧅ࡀࡾ࠿ࡡ࡞࠸㹿ࡑࡢࡓࡵࠊᮦᩱෆ㒊ࡢ㗪㐀Ḟ㝗ࡢ ṇ☜࡞ᢕᥱ࡜ホ౯ࡀᚲせ࡛࠶ࡿࠋ ᮦᩱෆ㒊ࡢ㗪㐀Ḟ㝗ࢆㄪᰝࡍࡿ࡟ࡣᗄࡘ࠿ࡢ㠀◚ቯ᳨ᰝᡭἲࡀ࠶ࡿࡀࠊ᭱㏆࡛ࡣ X ⥺࡟ࡼࡿ᩿ᒙ᧜ᙳ ᢏ⾡㸦Computing Tomography : CT㸧ࡀὀ┠ࡉࢀ࡚࠸ࡿࠋ㏆ᖺ࡟࡞ࡗ࡚ࠊ⏘ᴗ⏝ X ⥺ CT ⿦⨨ࡢග※ࡢȣ ࢫ࣏ࢵࢺ໬ࡀ㐍ࡳࠊᮦᩱෆ㒊ࡢᚤᑠ࡞Ḟ㝗ࡲ࡛ࡶ⏘ᴗ⏝ X ⥺ CT ⿦⨨࡟ࡼࡗ᳨࡚ฟࡀྍ⬟࡜࡞ࡾࡘࡘ࠶ ࡿࡀࠊⴭ⪅ࡽࡣࡑࢀ࡟ඛ❧ࡕࠊ㧗㍤ᗘ࣭㧗࢚ࢿࣝࢠ࣮࡛ᖹ⾜ᗘࡀ㧗࠸኱ᆺᨺᑕග᪋タ㸦SPring-8㸧ࡢᨺ ᑕගࢆ฼⏝ࡋࡓ CT㸦ᨺᑕග CT㸧ࡢ◊✲ࢆ⾜ࡗ࡚ࡁࡓࠋࡑࡢ㐣ཤࡢ୍㐃ࡢ◊✲࡟ࡼࡾࠊⴭ⪅ࡽࡣ㏻ᖖࡢ ⑂ປヨ㦂࡛౑⏝ࡉࢀࡿࢧ࢖ࢬ㸦┤ᚄᩘ mm㸧ࡢ࢔࣑ࣝࢽ࣒࢘ྜ㔠୸Წ࡟࠾࠸࡚ࠊヨᩱෆ㒊ࡢ㗪㐀Ḟ㝗ࡢ ᵝᏊࡸ⑂ປࡁ⿣㐍ᒎᣲື࡟ࡘ࠸࡚ࠊ㠀◚ቯ࡛୕ḟඖⓗ࡟ほᐹࡍࡿᡭἲࢆ☜❧ࡋࡓ 1)-4)_{ࠋᮏ◊✲࡛ࡣᮦᩱ} ෆ㒊ࡢ㗪㐀Ḟ㝗ࢆ㉳Ⅼ࡜ࡍࡿ⑂ປ◚ቯࡢ㜵Ṇࢆ୺ࡓࡿ┠ⓗ࡜ࡋࠊᨺᑕග CT ࢆ⏝࠸ࡓᮦᩱෆ㒊ࡢ㗪㐀Ḟ 㝗ㄪᰝ࡜ࠊᛂຊᣑ኱ಀᩘࢆ⏝࠸ࡓᐃ㔞ⓗホ౯ࢆヨࡳࡓࠋ

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౪ヨᮦ࠾ࡼࡧᐇ㦂᪉ἲ ౪ヨᮦ࠾ࡼࡧヨ㦂∦ᙧ≧ᐇ㦂ᮦᩱ ౪ヨᮦ࡟ࡣᕷ㈍ࡢ Al-Si-Mg ⣔㗪㐀࢔࣑ࣝࢽ࣒࢘ྜ㔠ࡢ AC4CH ࢆ౑⏝ࡋࡓࠋ⣲ᮦ࡬ࡢ㗪㎸ࡳࡣࠊ㗪㐀 Ḟ㝗ࡢⓎ⏕ࢆ㜵Ṇࡍࡿࡓࡵࡢ≉ู࡞⁐‮ฎ⌮࡞࡝ࢆ᪋ࡉࡎࠊ㔠ᆺࢆ⏝࠸ࡿ㏻ᖖࡢ㔜ຊ㗪㐀࡟࡚ࠊᗏ㠃ᖜ ⣙ 150mm × ᗏ㠃ཌࡉ⣙ 22mm × 㧗ࡉ⣙ 100mm ࡢ⯚ᙧࣈࣟࢵࢡࢆసᡂࡋࡓࠋࡑࡢᚋࠊ⯚ᙧࣈࣟࢵࢡ࡟ࡘ ࠸࡚ࡣࠊ⁐య໬㸦813K × 4hrs ಖᣢᚋỈ෭㸧࡜᫬ຠ㸦433K × 4hrs㸧ࡢ T6 ⇕ฎ⌮ࢆ᪋ࡋࡓࠋᮏ◊✲࡛౑⏝ ࡍࡿヨ㦂∦ࡣࠊᅗ 1 ࡟♧ࡍ᭱ᑠ㒊┤ᚄ 7mm ࡢ༢⣧࡞◁᫬ィᆺࡢᅇ㌿᭤ࡆ⑂ປヨ㦂∦࡛࠶ࡾࠊ⣲ᮦࡢ⯚ ᙧୗ㠃࠿ࡽࡢ㧗ࡉ⣙ 30mm ࡢ఩⨨࡜ヨ㦂∦ࡢ୰ᚰ㍈ࡀ࡯ࡰ୍⮴ࡍࡿࡼ࠺࡞఩⨨࠿ࡽ඲ 19 యษฟࡋࡓࠋ ヨ㦂∦ࡣᶵᲔຍᕤࡢᚋ࡟ࠊ୰ኸ㒊ࢆ㸡400 ࠿ࡽ㸡2000 ࡢ࢚࣓࣮ࣜ⣬ࢆ⏝࠸࡚◊☻ࡋࠊ᪕┙࡟ࡼࡿຍᕤയ ࢆ㝖ཤࡋࡓࠋࡇࡢヨ㦂∦ᙧ≧ࡢᛂຊ㞟୰ಀᩘࡣȘ=1.05 ࡛࠶ࡿࠋ౪ヨᮦࡢගᏛ㢧ᚤ㙾ほᐹ࡟ࡼࡿ⤌⧊ほ ᐹ⤖ᯝࢆᅗ 2 ࡟♧ࡍࠋ⤌⧊ࡣᆒ㉁࡞ࢹࣥࢻࣛ࢖ࢺ≧⤌⧊࡛࠶ࡾࠊ⤖ᬗ⢏ࡢ኱ࡁࡉࢆ⾲ࡍᣦᶆࡢ஧ḟࢹࣥ ࢻࣛ࢖ࢺ࢔࣮࣒㛫㝸㸦DAS II㸸dendrite arm spacing㸧ࡀ⣙ 30Pm ࡛࠶ࡗࡓࠋ

ᐇ㦂᪉ἲ ᮏ◊✲࡛ࡣࠊヨ㦂∦ෆ㒊࡟Ꮡᅾࡍࡿ㗪㐀Ḟ㝗࠿ࡽࡢ⑂ປࡁ⿣Ⓨ⏕ᣲືࢆᐃ㔞ⓗ࡟ホ౯ࡍࡿࡓࡵࠊ௨ୗ ࡢᡭ㡰࡛◊✲ࢆᐇ᪋ࡋࡓࠋ 1㸬ᨺᑕග CT ࡟ࡼࡿヨ㦂∦ࡢࢫࢡ࣮ࣜࢽࣥࢢ ヨ㦂∦ෆ㒊ࡢ㗪㐀Ḟ㝗ㄪᰝ࠾ࡼࡧィ ࡜ࠊ⑂ປヨ㦂⏝ࡢヨ㦂∦ࡢ㑅ᐃࠋ 2㸬㑅ᐃࡋࡓヨ㦂∦࡬ࡢ࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮ ⑂ປヨ㦂᫬ࡢ⾲㠃ࡁ⿣Ⓨ⏕ࢆᢚไࡍࡿࡓࡵࠊヨ㦂∦⾲㠃࡬ᅽ⦰ṧ␃ᛂຊࢆ௜୚ࠋ 3㸬⑂ປヨ㦂ࡢᐇ᪋ 㗪㐀Ḟ㝗ࡢᐃ㔞ⓗホ౯ጇᙜᛶࡢ☜ㄆࠋ ヨ㦂∦ࡢࢫࢡ࣮ࣜࢽࣥࢢ ࡲࡎ⏝ពࡋࡓ඲࡚ࡢヨ㦂∦࡟ࡘ࠸࡚ࠊᨺᑕග CT ࢆ⏝࠸ࡓෆᅾḞ㝗ࡢᙧ≧ࠊ఩⨨ࠊ㔞࡞࡝ࢆㄪᰝࡋࡓࠋ ᨺᑕග CT ࡣࠊ⊂❧⾜ᨻἲே ⌮໬Ꮫ◊✲ᡤࡀᡤ᭷ࡋࠊබ┈㈈ᅋἲே 㧗㍤ᗘග⛉Ꮫ◊✲ࢭࣥࢱ࣮ 㸦JASRI㸧ࡀ⟶⌮࣭㐠㌿ࢆ⾜࠺ࠊරᗜ┴ࡢ᧛☻⛉Ꮫබᅬ㒔ᕷ࡟࠶ࡿ኱ᆺᨺᑕග᪋タ㸦SPring-8㸧ࢆ฼⏝ࡋ

Fig.2 Microstructure of tested material. 400Pm Unit : mm

Fig. 1 Shape of the test specimen.

5 ȭ ȭ 0 ῝ ࢧ

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3

沖縄高専紀要第 7 号Ȫ2013ȫ

ࡓࠋࠕSPring-8ࠖ࡜ࡣࠊࠕSuper Photon ring-8 GeVࠖ࡟⏤᮶ࡋ࡚ྡ௜ࡅࡽࢀࠊග࡜࡯ࡰ➼ࡋ࠸㏿ᗘࡲ࡛ຍ㏿ ࡋࡓ㟁Ꮚࢆᙉຊ࡞☢ሙ࡛㐍⾜᪉ྥࢆ᭤ࡆࡓ᫬࡟Ⓨ⏕ࡍࡿ㟁☢Ἴ㸦ᨺᑕග㸧ࢆ฼⏝ࡋ࡚ྛ✀ࡢ ᐃࡀ⾜࠼ ࡿ᪋タ࡛࠶ࡾࠊ⵳✚ࣜࣥࢢ᪉ᘧࡢ X ⥺ග※㸦➨㸱ୡ௦ࢩࣥࢡࣟࢺࣟࣥᨺᑕග※㸧࡜ࡋ࡚ࡣୡ⏺᭱㧗ࡢ࢚ ࢿࣝࢠ࣮ࢆ᭷ࡋ࡚࠸ࡿᨺᑕග᪋タ࡛࠶ࡿࠋᮏ◊✲࡛ࡣࠊ⏘ᴗ฼⏝ࣅ࣮࣒ࣛ࢖ࣥࡢ BL19B2 ࢆ฼⏝ࡋࠊࡑ ࡢ➨ 1 ࣁࢵࢳ࡟࡚ ᐃࢆ⾜ࡗࡓࠋࡇࡢ࡜ࡁࡢࣁࢵࢳෆ㒊ࡢᵝᏊ࡜ほᐹయ⣔ࢆᅗ 3 ࡟♧ࡍࠋX ⥺࢚ࢿࣝࢠ ࣮ࢆ 28keV ࡟タᐃࡋࠊ㏻ᖖ࡛ࡣⓑⰍࡢᨺᑕගࢆ༢⤖ᬗ Si ࡟ࡼࡾ༢Ⰽ໬ࡋ࡚ࠊヨ㦂∦࡟ධᑕࡋࡓࠋヨ㦂 ∦㏱㐣ീࡢ᧜ᙳࡣヨ㦂∦࡜᳨ฟჾ㸦෭༷ CCD ࣓࢝ࣛ㸧ࡢ㊥㞳ࢆ 800mm ࡜ࡋ࡚ࠊヨ㦂∦ࡢ᭱ᑠ᩿㠃఩⨨ ࢆ୰ᚰ࡜ࡍࡿཌࡉ⣙ 4mm ࡢ㡿ᇦࢆᑐ㇟࡟⾜ࡗࡓࠋࡇࡢほᐹయ⣔࡛ࡢᐇຠⓗ࡞ࣆࢡࢭࣝࢧ࢖ࢬࡣ⣙ 2.85Pm/pixel ࡛࠶ࡿࠋヨ㦂∦ࡢ෌ᵓᡂ࡟ᚲせ࡞㏱㐣ീࡣ 0~180 ᗘࡲ࡛ 0.5 ᗘࡈ࡜࡟ࠊ✚⟬᫬㛫 2 ⛊࡟࡚ ྲྀᚓࡋࡓࠋ࡞࠾ࠊ⏬ീ෌ᵓᡂ࡟࠶ࡓࡗ࡚ࡣࠊSPring-8 ഃ࡛ᥦ౪ࡋ࡚࠸ࡿࢥ࣮ࣥ࣎ࣜࣗࢩ࣭ࣙࣥࣂࢵࢡࣉ ࣟࢪ࢙ࢡࢩࣙࣥ࢔ࣝࢦࣜࢬ࣒࡟ᇶ࡙࠸ࡓ෌ᵓᡂࢯࣇࢺࢆ౑⏝ࡋࡓࠋ඲ヨ㦂∦࡟ࡘ࠸࡚෌ᵓᡂീࢆసᡂࡋ ࡚Ḟ㝗ࢆྍど໬ࡋࡓᚋࠊᮏ◊✲࡛ࡣヨ㦂∦ෆ㒊࠿ࡽࡢ⑂ປࡁ⿣Ⓨ⏕ࢆᑐ㇟࡜ࡍࡿࡓࡵࠊヨ㦂∦ࡢ㍈᪉ྥ ㏱㐣ീ࠿ࡽෆ㒊࡟㐺ᙜ࡞኱ࡁࡉࡢḞ㝗ࡀ࠶ࡿヨ㦂∦ࢆ㑅ูࡋࡓࠋࡇࡢ㑅ู࡟ࡘ࠸࡚ࡣᚋ㏙ࡍࡿࠋ

(b) Experimental setup for CT

(a) Inside measuring hutch No.1of BL19B2

Fig.3 Synchrotron radiation CT

࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮ 㑅ูࡋࡓヨ㦂∦ࢆ⑂ປヨ㦂ࡋ࡚ࠊᮦᩱෆ㒊ࡢḞ㝗࠿ࡽ⑂ປ◚ቯࡉࡏࡿࡓࡵ࡟ࠊヨ㦂∦⾲㠃ࢆ㉳Ⅼ࡜ࡍ ࡿ⑂ປ◚ቯࢆ㜵Ṇࡍࡿᚲせࡀ࠶ࡿࠋᮏ◊✲࡛ࡣࡇࡢ┠ⓗࡢࡓࡵ࡟ࠊඛ࡟㑅ᐃࡋࡓヨ㦂∦࡟ᑐࡋ࡚࣮ࣞࢨ ࣆ࣮ࢽࣥࢢฎ⌮ࢆ᪋ࡋࡓࠋ࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮࡜ࡣࠊᅗ 4 ࡟♧ࡍࡼ࠺࡟ࠊࣃࣝࢫ࣮ࣞࢨࢆỈ୰࡛㔠ᒓ ᮦᩱ⾲㠃࡟↷ᑕࡋࠊࡑࡢ࡜ࡁ࡟Ⓨ⏕ࡍࡿ㔠ᒓࣉࣛࢬ࣐ࡢ⭾ᙇ࢚ࢿࣝࢠ࣮ࢆỈࡢ័ᛶຊ࡟ࡼࡗ࡚ᢚ࠼㎸ࡳࠊ ᮦᩱ୰࡟ᙎᛶἼࢆⓎ⏕࣭ఏ᧛ࡉࡏ࡚ࣆ࣮ࢽࣥࢢฎ⌮ࡍࡿᢏ⾡࡛࠶ࡿࠋᮏ◊✲࡛ࡣඹⴭ⪅ࡽࡀ㛤Ⓨࡋࡓ Nd:YAG࣮ࣞࢨࡢ➨ 2 㧗ㄪἼࢆ⏝࠸ࡿ᪥ᮏᘧ࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮ࢆ㐺⏝ࡋࡓࠋࡇࡢ࣮ࣞࢨࣆ࣮ࢽࣥࢢ ฎ⌮࡟ࡼࡗ࡚ヨ㦂∦⾲㠃㏆ഐ࡟ᅽ⦰ṧ␃ᛂຊࢆ௜୚ࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡾ 5)-6)_{ࠊࡇࡢᅽ⦰ṧ␃ᛂຊࢆ฼} ⏝ࡋ࡚⾲㠃࠿ࡽࡢࡁ⿣Ⓨ⏕ࢆᢚไࡍࡿࠋ࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮ࡣ㐣ཤࡢ◊✲⤖ᯝࢆࡶ࡜࡟⾲ 1 ࡢ᮲௳࡜ ࡋࡓ 5)_{ࠋࡇࡢฎ⌮᮲௳࡛௜୚ࡉࢀࡿᅽ⦰ṧ␃ᛂຊࡣࠊ㐣ཤࡢ◊✲⤖ᯝ࠿ࡽ⾲㠃㏆ഐ࡛ 100MPaࠊ⾲㠃ୗ} 1mm⛬ᗘ࡛࡯ࡰ 0MPa ࡜࡞ࡿ┤⥺ศᕸ࡜௬ᐃࡋࡓ5)ࠋ SPring-8 Slit 1 Slit 2 Si(111) Monochromator X-ray CCD camera BL19B2 Sample 800mm

(5)

⑂ປヨ㦂 ࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮ࡋࡓヨ㦂∦ࢆ⑂ປヨ㦂ࡍࡿࡇ࡜࡛ࠊヨ㦂∦ෆ㒊ࡢ㗪㐀Ḟ㝗ࢆ㉳Ⅼ࡜ࡋ࡚⑂ປ◚ ቯࢆ⏕ࡌࡿ࠿☜ㄆࡋࠊ㗪㐀Ḟ㝗ࡢᛂຊᣑ኱ಀᩘ࡟ࡼࡿホ౯ࡀ㐺ษ࡛࠶ࡗࡓ࠿᳨ウࡍࡿࠋ㐣ཤࡢ◊✲࡟ࡼ ࡗ࡚ᚓࡽࢀࡓྠ୍ᮦ㸦AC4CH-T6 ᮦ㸧ࡢ⑂ປヨ㦂⤖ᯝ㸦S-N ≉ᛶ㸧ࢆᅗ 5 ࡟♧ࡍ5)_{ࠋᅗ୰ࠕNDࠖࡀ㏻ᖖ} ࡢ㗪㐀࡟ࡼࡗ࡚స〇ࡋࡓ㗪㐀Ḟ㝗ࡢከ࠸ヨ㦂∦ࠊᅗ୰ࠕDGࠖࡀ㗪㐀᫬ࡢ⁐‮⬺࢞ࢫฎ⌮࡟ࡼࡗ࡚㗪㐀 Ḟ㝗ࡢⓎ⏕ࢆᢚไࡋࡓヨ㦂∦ࠊࡑࡋ࡚ᅗ୰ࠕDG-LPࠖࡀࠕDGࠖᮦ࡟࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮ࢆ᪋ࡋࡓヨ㦂 ∦࡛࠶ࡿࠋྛᮦࡢ⑂ປ㝈ᗘ㸦107_{ᅇ⑂ປᙉᗘ㸧ࡣࠊND ᮦ㸸100MPaࠊDG ᮦ㸸130MPaࠊDG-LP ᮦࡀ 160MPa}

࡛࠶ࡿࠋࡇࡢヨ㦂⤖ᯝࢆᇶ࡟ࠊヨ㦂∦ࡢෆ㒊ほᐹ࡟ࡼࡗ᳨࡚ฟࡉࢀࡓ㗪㐀Ḟ㝗ࡢ኱ࡁࡉ࡟ࡼࡗ࡚ࠊ160MPaࠊ 180MPaࠊ200MPa ࡢ࠸ࡎࢀ࠿ࡢᛂຊ᣺ᖜ࡟࡚⑂ປヨ㦂ࢆᐇ᪋ࡍࡿࡇ࡜࡜ࡋࡓࠋ⑂ປヨ㦂࡟ࡣࠊᅗ 6 ࡟♧ ࡍⴭ⪅ࡽࡢ㛤Ⓨࡋࡓ஧㐃ᘧᑠᆺ∦ᣢࡕᅇ㌿᭤ࡆ⑂ປヨ㦂ᶵ㸦ᅇ㌿ᩘ 3000rpm㸧ࢆ౑⏝ࡋࡓ4)_ࠋ

Fig.5 S-N diagram of AC4CH-T6 material5). Fig.6 Cantilever type fatigue machine.

104 105 106 107

100 200 300

Number of cycles to failure N_f , cycles

S tr es s a m plitude V a , MP a DG–LP DG ND /HQV PDWHULDO 3ODVPD /DVHU ,Q WKH ZDWHU 6KRFN ZDYH

Fig.4 Laser Peening treatment.

Pulse energy

Spot diameter

Pulse number density

100 [mJ]

0.6 [mm]

27.3 [pulse/mm

2

]

(6)

5

(7)

ึᮇᑍἲࢆᑐ㇟࡜ࡋ࡚ᛂຊᣑ኱ಀᩘࡢ⟬ฟࢆ⾜ࡗࡓࠋ౛࡜ࡋ࡚ヨ㦂∦ No.2008-5 ࡟㛵ࡍࡿᛂຊᣑ኱ಀᩘ ࡢィ⟬⤖ᯝࢆᅗ 8 ࡟♧ࡍࠋࡇࡢヨ㦂∦࡟ᑐࡋ࡚ࡣࠊ㈇Ⲵᛂຊ᣺ᖜ࡜ࡋ࡚ 200MPa ࢆ᝿ᐃࡋ࡚࠸ࡿࠋ AC4CH-T6ᮦࡢ㐣ཤࡢ◊✲࠿ࡽࠊ㗪㐀Ḟ㝗ࡢᛂຊᣑ኱ಀᩘࡀ 1.5MPam1/2ࢆ㉸࠼ࡿ࡜ࡁ⿣ࡢⓎ⏕ࡀண᝿ࡉ ࢀࡇ࡜࠿ࡽ8) 9)_{ࠊ ౛࠼ࡤᅗ 8 ࡟♧ࡉࢀࡓ㗪㐀Ḟ㝗 DࠊEࠊF ࡣ࠸ࡎࢀࡶ⑂ປࡁ⿣ࡀⓎ⏕ࡍࡿ᮲௳ࢆ‶ࡓ} ࡋ࡚࠸ࡿࡇ࡜࡟࡞ࡿࠋ ⑂ປヨ㦂࡜◚㠃ほᐹ 㑅ᐃࡋࡓヨ㦂∦࡟࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮ࢆᐇ᪋ࡋࠊヨ㦂∦ẖ࡟タᐃࡋࡓᛂຊ᣺ᖜ࡛⑂ປヨ㦂ࢆ⾜ࡗࡓ ⤖ᯝࠊ඲࡚ࡢヨ㦂∦ࡀ⑂ປ◚ቯࡋࡓࠋᮏ◊✲࡛ࡣ౛࡜ࡋ࡚ࠊヨ㦂∦ No.2008-5 ࡟ࡘ࠸᳨࡚ウࢆ⾜࠺ࠋヨ㦂∦ No.2008-5 ࡢ⑂ປ◚㠃ࡢ࣐ࢡࣟ෗┿ࢆᅗ 9 ࡟♧ࡍࠋ࣐ࢡࣟ෗┿࠿ࡽࡣᅗ୰▮༳㒊ศ࡟⑂ປࡁ⿣ࡢⓎ ⏕㉳Ⅼࡀ࠶ࡿࡇ࡜ࡀࢃ࠿ࡿࠋᅗ 8 ࡟♧ࡋࡓࡼ࠺࡟ࠊᮏヨ㦂∦୰࡟Ꮡᅾࡍࡿẚ㍑ⓗ኱ࡁ࡞୕ಶࡢ㗪㐀Ḟ㝗 ࡢᛂຊᣑ኱ಀᩘࡣࡁ⿣ࡢⓎ⏕ୗ㝈⏺ 1.5MPam1/2_{ࢆୖᅇࡿ್࡛࠶ࡾࠊ≉࡟᭱ࡶ㧗࠸ᛂຊᣑ኱ಀᩘ࡜࡞ࡗࡓ} 㗪㐀Ḟ㝗 D ࡀ⑂ປࡁ⿣ࡢⓎ⏕㉳Ⅼ࡜࡞ࡿࡇ࡜ࡀண᝿ࡉࢀࡓࠋࡋ࠿ࡋࠊ⑂ປ◚㠃ࢆ㉮ᰝᆺ㟁Ꮚ㢧ᚤ㙾㸦SEM㸧࡟ࡼࡗ࡚ほᐹࡋࡓ⤖ᯝࢆᅗ 10 ࡟♧ࡍࡼ࠺࡟ࠊ⑂ປࡁ⿣Ⓨ⏕㉳Ⅼ௜㏆࡟ࡣ⣽㛗࠸⥺≧ࡢ㗪㐀Ḟ 㝗ࡀほᐹࡉࢀࡓࠋࡇࡢ㗪㐀Ḟ㝗ࡣࠊᨺᑕග CT ࡟ࡼࡗ࡚ほᐹࡉࢀࡓ㗪㐀Ḟ㝗 F ࡜᥎ ࡉࢀࡿࠋᅗ 9 ࡢ⑂ ປ◚㠃ࡢ࣐ࢡࣟ෗┿࠿ࡽࡣࠊᅗ୰ࡢ G ࡢ఩⨨࡟ࡶ᭱⤊◚㠃࡜ࡣ␗࡞ࡿᵝ┦ࡀ☜ㄆࡉࢀࡓࠋᨺᑕග CT ࡢ ほᐹ࡟ࡼࢀࡤࠊᅗ୰ G ࡢ఩⨨࡟ࡣ㗪㐀Ḟ㝗 E ࡀᏑᅾࡋ࡚࠸ࡿ㡿ᇦ࡛࠶ࡿࡀࠊ᫂░࡞㗪㐀Ḟ㝗ࡣ☜ㄆࡉࢀ Defect D E F Area [Pm2_] 2.6810 5_2.42₁₀5_7.92₁₀4 KImax [MPam1/2 ] 3.14 2.60 2.07

Fig.8 Example of stress intensity factor estimation of defects. (Specimen No.2008-5)

Defect D Defect E

Defect F

1mm

Fig.9 Macro image of fracture surface. G

Crack initiation site

Specimen No.2008-5 Va : 200 [MPa]

Nf : 3896704 [cycles]

(8)

沖縄高専紀要第 7 号Ȫ2013ȫ 7 ࡞࠿ࡗࡓࠋࡇࡢ఩⨨ࢆ SEM ࡟ࡼࡗ࡚ヲ⣽࡟ほᐹࡋࡓ࡜ࡇࢁࠊ◚㠃ࡣᅗ 11 ࡟♧ࡍࡼ࠺࡟㠀ᖖ࡟ᖹᆠ࡞㠃 ࡛ᵓᡂࡉࢀ࡚࠸ࡿࡇ࡜࠿ࡽࠊᨃ࡬ࡁ㛤◚㠃(ὀ1)_{࡜᥎ ࡉࢀࡓࠋࡲࡓࠊࡇࡢᖹᆠ࡞◚㠃ୖ࡟ࡣࠊᚤᑠ࡞࣎} ࢖ࢻ(ὀ2)_{ࡀ↓ᩘ࡟ほᐹࡉࢀࡓࠋ} ◚ቯ㉳Ⅼ࡜㗪㐀Ḟ㝗ᙧ≧ ᛂຊᣑ኱ಀᩘࡢ್ࡀࡁ⿣Ⓨ⏕ୗ㝈⏺್ࡼࡾࡶ኱ࡁ࠸࡜ぢ✚ࡶࡽࢀࡓ㗪㐀Ḟ㝗࡟࠾࠸࡚ࠊ⑂ປࡁ⿣Ⓨ⏕ ㉳Ⅼ࡜࡞ࡽ࡞࠿ࡗࡓ⌮⏤࡟ࡘ࠸᳨࡚ウࡍࡿࠋ㗪㐀Ḟ㝗ࡢᛂຊᣑ኱ಀᩘ࡟ࡘ࠸࡚ࡣࠊ㏻ᖖࠊⲴ㔜㍈᪉ྥ࡬ ᢞᙳࡋࡓ㠃✚ࢆࡶ࡜࡟ᮧୖࡽࡢ᪉ἲࢆ⏝࠸࡚ィ⟬࣭ホ౯ࡉࢀࡿࡓࡵࠊᮏ◊✲࡟࠾࠸࡚ࡶほᐹࡉࢀࡓ㗪㐀 Ḟ㝗ࢆ㍈᪉ྥ࡟ᢞᙳࡋࡓ㠃✚ࢆ⏝࠸࡚⟬ฟࡋࡓࠋᙜึࠊ㗪㐀Ḟ㝗ࡣᅗ 12 ࡟♧ࡍࡼ࠺࡞ẚ㍑ⓗ኱ࡁ࡞ᘬ ࡅᕢࡢࡼ࠺࡞ࡶࡢࢆண᝿ࡋ࡚࠸ࡓࡀࠊ◚㠃ୖ࡟⌧ࢀࡓࡢࡣᅗ 10 ࡸᅗ 11 ࡟♧ࡋࡓࡼ࠺࡞ᑠࡉ࡞࣎࢖ࢻ≧ Ḟ㝗ࡢ㞟ྜయ࡛࠶ࡗࡓࠋࡑࡇ࡛ࠊᨵࡵ࡚ᨺᑕග CT ࡢ෌ᵓᡂ⏬ീ࡟ࡘ࠸࡚෌☜ㄆࢆ⾜ࡗࡓࠋ 㗪㐀Ḟ㝗ࡢᛂຊᣑ኱ಀᩘࡀ᭱ࡶ኱ࡁࡃぢ✚ࡶࡽࢀࡓ࡟ࡶ࠿࠿ࢃࡽࡎࠊ⑂ປ◚㠃ୖ࡛ほᐹࡉࢀ࡞࠿ࡗࡓ 㗪㐀Ḟ㝗 D ࡟ࡘ࠸࡚ࠊࡑࡢ୕ḟඖᙧ≧ࢆㄪᰝࡋࡓࠋ㗪㐀Ḟ㝗ࢆ୕ḟඖⓗ࡟⌧ࡋࡓࡶࡢࡀᅗ 13 ࡛࠶ࡿࠋ ࡇࡢᅗ࡟࠾࠸࡚ࠊヨ㦂∦㍈᪉ྥࡣ O-Z ᪉ྥ࡟ᑐᛂࡍࡿࠋࡍ࡞ࢃࡕᅗ 8 ࡢヨ㦂∦㍈᪉ྥ࡟ᑐࡍࡿ㗪㐀Ḟ㝗 ࡢᢞᙳീࡣᅗ 13 ࡢ X-O-Y 㠃࡟┦ᙜࡍࡿࠋࡇࡢᅗ 13 ࡢ Z-O-X 㠃ࠊY-O-Z 㠃࠿ࡽࠊ㗪㐀Ḟ㝗 D ࡣヨ㦂∦ ㍈᪉ྥ࡟ 200Pm ௨ୖࡢ⠊ᅖ࡟ศᕸࡋࡓᚤᑠ࡞࣎࢖ࢻ≧Ḟ㝗ࡢ㞟ྜయ࡛࠶ࡿࡇ࡜ࡀࢃ࠿ࡿࠋࡘࡲࡾࠊࡇࡢ ࡼ࠺࡞㗪㐀Ḟ㝗ࡢሙྜ࡟ࡣࠊ㍈᪉ྥ࡟ᢞᙳࡍࡿࡇ࡜ࡀᚲࡎࡋࡶ㐺ษ࡞ホ౯᪉ἲ࡛ࡣ↓࠸࡜࠸࠼ࡿࠋ ⥆࠸࡚ࡁ⿣Ⓨ⏕㉳Ⅼ௜㏆࡟ほᐹࡉࢀࡓ㗪㐀Ḟ㝗 F ࡟ࡘ࠸࡚ࡶྠᵝࡢㄪᰝࢆ⾜ࡗࡓࠋ㗪㐀Ḟ㝗 F ࢆ୕ḟ ඖⓗ࡟⌧ࡋࡓࡶࡢࢆᅗ 14 ࡟♧ࡍࠋᅗ 13 ࡜ྠᵝ࡟ࠊࡇࡢᅗ࡟࠾࠸࡚ࡶヨ㦂∦㍈᪉ྥࡣ O-Z ᪉ྥ࡟ᑐᛂࡍ ࡿࠋ㗪㐀Ḟ㝗 F ࡣ㍈᪉ྥ࡟ 150Pm ⛬ᗘࡢ⠊ᅖ࡟ศᕸࡋࡓᚤᑠ࡞࣎࢖ࢻ≧Ḟ㝗ࡢ㞟ྜయ࡛࠶ࡿࡇ࡜ࡀࢃ ࠿ࡿࠋᅗ 10 ࡟♧ࡋࡓ◚㠃ࡢ SEM ほᐹ࡟࠾࠸࡚ࠊ㗪㐀Ḟ㝗 F ࡣ☜࠿࡟㉳Ⅼ௜㏆࡟☜ㄆࡉࢀ࡚࠸ࡿࡇ࡜࠿ 150Pm 500Pm

Fig.10 Fracture surface observed by SEM. (Crack initiation site)

Fig.11 Fracture surface observed by SEM. (Area G in Fig.9) (ὀ 1) ᨃ࡬ࡁ㛤◚ቯ 㔠ᒓࡢࡐ࠸ᛶ◚ቯ㸦ረᛶኚᙧࢆకࢃࡎ࡟ᛴ㏿࡟㐍ᒎࡍࡿ◚ቯ㸧ࡢ୍✀࡛࠶ࡾࠊ࡬ࡁ㛤◚ቯ㸦≉ᐃࡢ⤖ᬗ㠃㸦࡬ࡁ㛤㠃㸧࡛ศ㞳 ◚᩿ࡍࡿ◚ቯᵝᘧ㸧ࡼࡾࡶ◚ቯ㏿ᗘࡀ㐜࠸ሙྜ࡟⏕ࡌࡿ◚ቯᵝᘧࡢࡇ࡜ࠋᇶᮏⓗ࡟ࡣࡐ࠸ᛶ◚ቯ࡛ࡣ࠶ࡿࡀࠊ࡬ࡁ㛤◚ቯࡢࡼ ࠺࡟᫂░࡞⤖ᬗ⢏ࡢ๭ࢀ࡞࡝ࡀほᐹࡉࢀ࡞࠸ሙྜ࡟ࠊࠕᨃ࡬ࡁ㛤◚ቯࠖ࡜⛠ࡍࡿࡇ࡜ࡀከ࠸ࠋ (ὀ 2) ࣎࢖ࢻ ࡇࡢሙྜࠕẼᏍࠖ࡜ࡶゝ࠸ࠊ≀య࡟ྵࡲࢀࡿᚤᑠ࡞✵Ὕࡢࡇ࡜ࠋ

(9)

ࡽࠊ⑂ປࡁ⿣ࡢⓎ⏕࡟㛵୚ࡋࡓྍ⬟ᛶࡀ࠶ࡿࠋࡋ࠿ࡋࠊࡇࡢ㗪㐀Ḟ㝗ࡀࡁ⿣Ⓨ㉳Ⅼ࡜࡞ࡗࡓ࠿ྰ࠿ࡣ୙ ࡛᫂࠶ࡿࠋ࠸ࡎࢀ࡟ࡋ࡚ࡶࠊࡇࡢࡼ࠺࡞ᚤᑠ࡞࣎࢖ࢻ≧Ḟ㝗ࡢ㞟ྜయ࡛࠶ࡿ㗪㐀Ḟ㝗࡟࠾࠸࡚ࠊⲴ㔜㍈ ᪉ྥ࡬ࡢᢞᙳ㠃✚ࢆࡶࡗ࡚௦⾲ᑍἲ࡜ࡍࡿᛂຊᣑ኱ಀᩘࡢホ౯ᡭἲࡣࠊ㗪㐀Ḟ㝗ࡢ㐣኱ホ౯࡜࡞ࡿྍ⬟ ᛶࡀ࠶ࡿࠋ㐣ᑠホ౯࡛ࡣ࡞࠸ࡓࡵᏳ඲ୖࡢၥ㢟ࡣ࡞࠸ࡀࠊࡇࡢࡼ࠺࡞࣎࢖ࢻ≧Ḟ㝗ࡢ㞟ྜయࡢホ౯࡟ࡘ ࠸࡚ࡣࠊⲴ㔜㍈᪉ྥ࡬ࡢศᕸ≧ែ࡞࡝ࡶྵࡵ࡚᭦࡞ࡿ᳨ウࡀᚲせ࡛࠶ࡿࠋ ⤖ ゝ㗪㐀࢔࣑ࣝࢽ࣒࢘ྜ㔠ࡢෆᅾḞ㝗ࢆᨺᑕග CT ࡟ࡼࡗ࡚ㄪᰝࡋࠊ㗪㐀Ḟ㝗࠿ࡽࡢࡁ⿣Ⓨ⏕࡜ᛂຊᣑ኱ ಀᩘ࡜ࡢ㛵ಀ࡟ࡘ࠸࡚ᐃ㔞ⓗ࡞ホ౯ࢆヨࡳࡓ⤖ᯝࠊ௨ୗࡢࡇ࡜ࡀ᫂ࡽ࠿࡜࡞ࡗࡓࠋ 1㸬ᑠࡉ࡞࣎࢖ࢻ≧ࡢḞ㝗ࡀヨ㦂∦㍈᪉ྥ࡬ศᩓࡋ࡚Ꮡᅾࡍࡿࡼ࠺࡞ሙྜࠊⲴ㔜㍈᪉ྥ࡬ࡢᢞᙳ㠃✚ ࢆᇶ‽࡜ࡋࡓᛂຊᣑ኱ಀᩘホ౯ࡣᚲࡎࡋࡶⓗ☜࡛ࡣ࡞࠸ࠋࡓࡔࡋࠊᏳ඲ഃ࡟ᛂຊᣑ኱ಀᩘࢆぢ✚ ࡶࡿࡓࡵࠊᐇ⏝ୖࡢၥ㢟ࡣ࡞࠸㸬 2㸬ᨺᑕග CT ࡟ࡼࡗ࡚࢔࣑ࣝࢽ࣒࢘ྜ㔠ෆ㒊࡟ᏑᅾࡍࡿḞ㝗ᙧ≧ࢆㄪᰝࡋࡓሙྜࠊほᐹࡉࢀࡓḞ㝗 ࡢ୕ḟඖᙧ≧࣭ศᕸ≧ἣ࡞࡝࠿ࡽࠊḞ㝗ࡢᛂຊᣑ኱ಀᩘࢆ㐺ษ࡟ホ౯ࡍࡿࡓࡵࡢᡭἲࢆ☜❧ࡍࡿ ᚲせࡀ࠶ࡿࠋ 100_Pm

Fig.12 Example of a casting defect of AC4CH4).

Fig.13 3D-image of the defect D in Fig.8

Z X Y O Y-O-Z X-O-Y Z-O-X 100_Pm Y Z O X Y O Z X O whole view

Fig.14 3D-image of the defect F in Fig.8

Z X Y O whole view X-O-Y Z-O-X Y-O-Z Y X O X Z O O Y Z 100Pm

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9 沖縄高専紀要第 7 号Ȫ2013ȫ ㅰ㎡ ᮏ◊✲ࡢ୍㒊ࡣࠊ㸦㈈㸧㧗㍤ᗘග⛉Ꮫ◊✲ࢭࣥࢱ࣮㸦JASRI㸧ࡢ኱ᆺᨺᑕග᪋タ㸦SPring-8㸧ࡢ⏘ᴗ⏝ ࣅ࣮࣒ࣛ࢖ࣥ㸦BL19B2㸧࡛ᐇ᪋ࡋࡓㄢ㢟␒ྕ 2007B1954ࠊ2008A1887 ࡢᡂᯝࡢ୍㒊࡛࠶ࡿࠋࡲࡓࠊ㸦♫㸧 ᪥ᮏ࢔࣑ࣝࢽ࣒࢘༠఍ࡢᖹᡂ 20 ᖺᗘࠊᖹᡂ 21 ᖺᗘ࡟࠾ࡅࡿࠕ࢔࣑ࣝࢽ࣒࢘◊✲ຓᡂࠖࡢᑐ㇟ㄢ㢟࡜ࡋ ࡚ᐇ᪋ࡋࡓࡶࡢ࡛࠶ࡿࠋ㛵ಀྛ఩࡟ㅰពࢆ⾲ࡍࡿࠋ ᘬ⏝ᩥ⊩ 㸯㸧బ㔝㞝஧ࠊᨻᮌΎᏕࠊ⛅⏣㈉୍ࠊஂಖ㐩ஓࠊబ⸨┾┤ࠊᲚཎሀኴ㑻ࠊ࣮ࣞࢨࣆ࣮ࢽࣥࢢฎ⌮ࡋࡓᮦ ᩱࡢ㧗࢚ࢿࣝࢠ࣮ᨺᑕග࡟ࡼࡿ㠀◚ቯホ౯ࠊᨺᑕගࠊ21ࠊ270㸫278ࠊ㸦2008㸧㸰㸧బ㔝㞝஧ࠊᨻᮌΎᏕࠊ㉺ᬛಖ㞝ࠊ⛅⏣㈉୍ࠊᲚཎሀኴ㑻ࠊᨺᑕගࢆ౑⏝ࡋࡓ࣐࢖ࢡࣟ CT ࡟ࡼࡿ࢔ ࣑ࣝࢽ࣒࢘ྜ㔠⑂ປࡁ⿣ࡢྍど໬ࠊᮦᩱࠊ57ࠊ395㸫400ࠊ㸦2008㸧

㸱㸧Y. SanoࠊM. ObataࠊK. AkitaࠊK. MasakiࠊY. OchiࠊH. SuzukiࠊM. SatoࠊK. KajiwaraࠊCharacterization of Laser-peened Materials by Synchrotron Radiation and Neutron Diffraction TechniquesࠊJikken Rikigakuࠊ7ࠊ 61㸫67ࠊ㸦2007㸧

㸲㸧K. MasakiࠊY. SanoࠊY. OchiࠊK. AkitaࠊK. KajiwaraࠊInvestigation of Fatigue Crack Behavior with Synchrotron Radiation on AC4CH Casting Aluminum AlloyࠊJ㸬Solid Mech. Mater. Eng.ࠊ2ࠊ1104㸫1113ࠊ㸦2008㸧. 㸳㸧Y. SanoࠊK. AkitaࠊK. MasakiࠊY. OchiࠊI. AltenbergerࠊB. ScholtesࠊLaser Peening without Coating as a Surface Enhancement TechnologyࠊJ. Laser Micro/Nanoengineeringࠊ1ࠊ161㸫166ࠊ㸦2006㸧

㸴㸧ᨻᮌΎᏕࠊ㉺ᬛಖ㞝ࠊ⇃㇂ὒᖹࠊబ㔝㞝஧ࠊෆ⸨ⱥᶞࠊᯇᮧ㝯ࠊ⁐‮ฎ⌮㗪㐀࢔࣑ࣝࢽ࣒࢘ྜ㔠ࡢ ⑂ປ≉ᛶ࡟ཬࡰࡍ࣮ࣞࢨࣆ࣮ࢽࣥࢢࡢᙳ㡪ࠊᮦᩱࠊ55ࠊ706㸫711ࠊ㸦2006㸧㸵㸧ᮧୖᩗᐅࠊ㔠ᒓ⑂ປ ᚤᑠḞ㝗࡜௓ᅾ≀ࡢᙳ㡪ࠊ㣴㈼ᇽࠊ16㸫17ࠊ㸦1993㸧㸶㸧㉺ᬛಖ㞝ࠊᨻᮌΎᏕࠊ࢔࣑ࣝࢽ࣒࢘ྜ㔠ࡢ㟼ⓗ࣭ືⓗᙉᗘ≉ᛶ࡟࠾ࡼࡰࡍ⤌⧊࠾ࡼࡧḞ㝗ࡢᙳ㡪ࠊ 㸦♫㸧㍍㔠ᒓᏛ఍◊✲㒊఍ሗ࿌᭩ࠊ46ࠊ31㸫36ࠊ㸦2005㸧㸷㸧ᨻᮌΎᏕࠊబ㔝㞝஧ࠊ㉺ᬛಖ㞝ࠊ⛅⏣㈉୍ࠊᯇᮧ㝯ࠊᲚཎሀኴ㑻ࠊ࣮ࣞࢨࣆ࣮ࢽࣥࢢ࡟ࡼࡿ AC4CH ᮦࡢ⑂ປࡁ⿣㐍ᒎᢚไ࡜PCT ᢏ⾡࡟ࡼࡿࡁ⿣ᙧ≧ࡢྍど໬ࠊ᪥ᮏᮦᩱᏛ఍ ➨ 28 ᅇ⑂ປࢩ࣏ࣥࢪ࣒࢘ ㅮ₇ண✏㞟ࠊ160㸫164ࠊ㸦2006㸧

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Kiyotaka Masaki㸯, Yuji Sano㸰

㸯_{Department of Mechanical Systems Engineering,}㸰_{Toshiba Corporation}

Fatigue fracture of casting aluminum alloy is influenced by fatigue crack initiation from a casting defect inside the material. In this study, visualization of casting defects by computing tomography (CT) with synchrotron radiation at SPring-8 was carried out for a casting aluminum alloy AC4CH. Quantitative evaluation by fracture mechanics was performed with the visualization results to estimate the effect of casting defects on the fatigue strength of the material. Compared to the rotating bending fatigue test results, the conventional method using root area parameter tends to overestimate the stress intensity factor of casting defects, depending on the shape and dimensions. Since the conventional method results in a conservative estimation of the stress intensity factor, the method is still useful in actual applications

Key word: Synchrotron radiation, Computing tomography, Casting aluminum alloy, Casting defects, Stress intensity factor