2013 Fiscal Year Final Research Report
Influence of Previous Particle Boundary on high-temperature strengths of PM superalloy
| Project/Area Number |
23560844
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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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| Research Field |
Structural/Functional materials
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
KAKEHI Koji 首都大学東京, 理工学研究科, 准教授 (70185726)
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| Project Period (FY) |
2011 – 2013
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| Keywords | ニッケル基超合金 / 粉末冶金 / 旧粉末粒子界面 / プラズマ回転電極法 / インコネル７１８ / 熱間静水圧法 |
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| Research Abstract |
PPB (prior particle boundary) is known to decrease the toughness and ductility of PM alloys. The forging process is generally applied after sintering by HIP to crush PPBs, which are caused by impurities on the surface of the powder. The PREP(Plasma Rotating Electrode Process) is known to capable of reducing impurities in refractory-metals powder. In this study, to reduce PPBs, PREP was applied to alloy 718 powder. The alloy powder was HIPed at a delta-subsolvus temperature to achieve a superfine grain and high strength. The influence of PREP treatment on tensile properties and the microstructure of P/M 718 were investigated. After PREP treatment, the impurities in the powder were reduced. The PREP was found to increase the density of the sintered specimen. However, it did not improve ductility as expected due to an insufficient reduction of the oxygen content and fine precipitates in PPB.
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