Condition of internal void closure with multi-axial stress induce in additive manufactured metallic body
| Project/Area Number |
20K05165
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 26050:Material processing and microstructure control-related
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| Research Institution | Gifu University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2021: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
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| Keywords | 積層造形 / ウェッジ鍛造 / 内部欠陥 / 未溶融欠陥 / 高強度 / 内部空孔 / 表面粗さ / 金属積層造形 / 塑性加工 / 空孔欠陥 / 空孔体積率 / 延性 / 粉末床 / SLM / 画像解析 / 微小空孔 / 多軸応力 / 鍛造 |
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| Outline of Research at the Start |
粉末床選択的レーザ溶融を用いた金属積層造形法で得られる造形物内の微小空孔に対し，多軸応力状態下における鍛造を施すことによってこれらを消失させる条件を学術的に検討する．当該手法において，低荷重でかつ大変形を付与する条件を塑性力学的に検討し，最適な応力比および導入すべきひずみの大きさと内部微小空孔の圧着条件との関係を解析的に検討することで，組織制御すなわち内部空孔圧着条件を明らかにする.
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| Outline of Final Research Achievements |
Powder bed fusion (PBF) and selective laser melting (SLM) method was used for maraging steel block manufacturing. Internal void volume fraction and mechanical properties of the products were investigated under the experimental condition of constant energy density with 4 combinations of laser scanning rate and hatching space distance. Micro tensile test specimens were cut out from the build blocks and tensile test was performed. In addition, the wedge forging process was proposed for the purpose of internal defect closure, and its experiment and finite element analyses were performed. As the result, the forging process realizes employment of large strain in low compression load.
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| Academic Significance and Societal Importance of the Research Achievements |
金属積層造形を用いて金型を製造する際，どうしても内部に微小空洞が残存し，これが製品の機械的特性を低下させる要因となりうる．現状では，熱間等方圧加圧法（HIP）処理などの後続加工によってこれらを減少させているが，必ずしも０とはならない．一方，塑性加工には鍛造という技術があり，内部中心近辺の欠陥を圧着する．しかしながら内部欠陥の理論的消失条件は必ずしも明らかにはなっていない．本研究では，積層造形における内部欠陥予測の基礎知見を得ること，同時に垂直方向偏差応力を効率よく増大させることで，低荷重で大ひずみを付与することが可能とするウェッジ鍛造法の機構を解明する．
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Report
(4 results)
Research Products
(2 results)
