Prediction of Development of Inhomogeneous Plastic Deformation and Fracture Based on Change in Elastic Height Distribution in Polycrystalline Metals

• Project/Area Number: 18H01337
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Okayama University
• Principal Investigator: Tada Naoya 岡山大学, 自然科学研究科, 教授 (70243053)
• Co-Investigator(Kenkyū-buntansha): 上森 武 岡山大学, 自然科学研究科, 准教授 (70335701) ; 坂本 惇司 岡山大学, 自然科学研究科, 助教 (50752052)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥17,940,000 (Direct Cost: ¥13,800,000、Indirect Cost: ¥4,140,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2019: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2018: ¥13,000,000 (Direct Cost: ¥10,000,000、Indirect Cost: ¥3,000,000)
• Keywords: 弾性不均一変形 / 塑性不均一変形 / 表面高度分布 / 多結晶金属材料 / 表面あれ

Outline of Final Research Achievements

Tensile tests were carried out using plate and thin sheet specimens of polycrystalline pure titanium. Microscopic inhomogeneous deformations under elastic and plastic conditions were discussed focusing on the deformation of thin sheet specimens where the effect of interior crystal grains was week. The following resutls were obtained. Height changes at the center of grains were correlated with those near the grain boundaries. Correlation between the height changes on the front and back surfaces changed when the deformation changed from elastic to plastic. The initiation of slip lines near the notch could be predicted by slip activity.

Academic Significance and Societal Importance of the Research Achievements

本研究では純チタンの微視的不均一変形を変形初期に相当する弾性状態から塑性状態まで詳細に観察・測定し，弾性不均一変形と塑性不均一変形の関係等を明らかにした．本材料では，塑性不均一変形が主としてすべりによって生じるが，切欠き材のような応力集中部が存在する場合を含め，すべり線の発生を予測する手法を提案した．すべりの発生予測や弾性不均一変形と塑性不均一変形の関係は，材料の破壊と深く関連するため，各種構造材料の破壊防止に有用であると考える．

Research Products

• [Journal Article] Prediction of the Fracture Location by Tensile Tests of Gray Cast Iron Based on the Dimensional Changes of Graphite Flakes (2021)
  • Author(s): Naoya Tada, Takeshi Uemori, Junji Sakamoto
  • Journal Title: Transactions of the ASME, Journal of Pressure Vessel Technology Volume: 143 Issue: 2 Pages: 1-8
  • DOI: 10.1115/1.4048063
  • NAID: 120007161126
  • Peer Reviewed
• [Journal Article] Finite Element Study of the Effect of Internal Crack on Surface Profile Change due to Low Loading of Turbine Blade (2020)
  • Author(s): Junji Sakamoto, Naoya Tada, Takeshi Uemori, Hayato Kuniyasu
  • Journal Title: Applied Sciences Volume: 10 Issue: 14 Pages: 1-14
  • DOI: 10.3390/app10144883
  • NAID: 120006877907
  • Peer Reviewed / Open Access
• [Journal Article] Analysis of the change of direct current potential difference and diameter distribution of thin pure titanium wire subjected to tensile and fatigue loads for fracture prediction (2020)
  • Author(s): 坂本惇司，高木佑輔，上森武，多田直哉
  • Journal Title: Transactions of the JSME (in Japanese) Volume: 86 Issue: 882 Pages: 19-00351-19-00351
  • DOI: 10.1299/transjsme.19-00351
  • NAID: 130007801826
  • ISSN: 2187-9761
  • Peer Reviewed / Open Access
• [Journal Article] Crystal Plasticity Finite Element Analysis of Effects of Microscopic Non-Uniform Deformation on Surface Roughness of Pure Titanium Sheet (2019)
  • Author(s): 上森武，柿原大毅，多田直哉
  • Journal Title: Journal of the Society of Materials Science, Japan Volume: 68 Issue: 6 Pages: 478-484
  • DOI: 10.2472/jsms.68.478
  • NAID: 130007665157
  • ISSN: 0514-5163, 1880-7488
  • Year and Date: 2019-06-15
  • Peer Reviewed / Open Access
• [Journal Article] Microscopic Elastic and Plastic Inhomogeneous Deformations and Height Changes on the Surface of a Polycrystalline Pure-Titanium Plate Specimen under Cyclic Tension (2018)
  • Author(s): Naoya Tada, Takeshi Uemori
  • Journal Title: Applied Sciences Volume: 8 Issue: 10 Pages: 1-16
  • DOI: 10.3390/app8101907
  • Peer Reviewed / Open Access
• [Presentation] 切欠きを有する純チタン薄膜試験片の引張に伴う結晶粒のすべり変形挙動に関する検 (2021)
  • Author(s): 石田諭史，多田直哉，上森武，坂本惇司，石丸恵太
  • Organizer: 日本機械学会中国四国支部第59期総会・講演会
• [Presentation] Microscopic Deformation of Thin Sheet of Polycrystalline Pure Titanium Under Tension (2020)
  • Author(s): Naoya TADA, Kentaro KISHIMOTO, Takeshi Uemori, Junji Sakamoto
  • Organizer: ASME 2020 Pressure Vessels and Piping Conference (PVP2020)
  • Int'l Joint Research
• [Presentation] 多結晶純チタンの繰返し引張後の微視的残留応力とすべり線の関係 (2020)
  • Author(s): 松本大樹，多田直哉，上森武，坂本惇司
  • Organizer: 日本材料学会第6回材料WEEK材料シンポジウム
• [Presentation] Slip Deformation of Crystal Grains in Semi-Circular Notched Thin Sheet Specimen of Pure Titanium during Tensile Test (2019)
  • Author(s): Takashi Ishida, Naoya Tada, Takeshi Uemori, Junji Sakamoto
  • Organizer: International Conference on Advanced Technology in Experimental Mechanics 2019 (ATEM ‘19)
  • Int'l Joint Research
• [Presentation] 低荷重負荷による表面性状変化を用いた内在欠陥の検出 (2019)
  • Author(s): 坂本惇司，國安隼人，多田直哉，上森武
  • Organizer: 日本機械学会材料力学部門M&M若手シンポジウム2019
• [Presentation] 純チタン薄膜の引張変形に伴う表面と裏面の微視的高度分布の関係 (2019)
  • Author(s): 岸本健太郎，多田直哉，上森武，坂本惇司
  • Organizer: 日本材料学会第5回材料WEEK材料シンポジウム
• [Presentation] 多結晶純チタンの引張りにおける結晶方位変化を考慮に入れた微視的すべり変形の評価 (2019)
  • Author(s): 佐藤宏樹，多田直哉，上森武，坂本惇司
  • Organizer: 日本金属学会2019年春期(第164回)講演大会
• [Presentation] Numerical Investigation of Relation between Surface Roughness and Microscopic Interior Deformation in Polycrystalline Pure Titanium Sheet (2018)
  • Author(s): Takeshi Uemori, Naoya Tada
  • Organizer: Asia-Pacific Conference on Fracture and Strength 2018
  • Int'l Joint Research
• [Presentation] 純チタン細線の引張試験における変形と直流電位差の関係 (2018)
  • Author(s): 高木佑輔，多田直哉，上森武
  • Organizer: 日本機械学会2018年度年次大会