1996 Fiscal Year Annual Research Report

ECAP法による超微細粒合金の組織と力学特性

Research Project

Project/Area Number	08242221
Research Institution	Kyushu University
Principal Investigator	根本実九州大学, 工学部, 教授 (90005265)
Co-Investigator(Kenkyū-buntansha)	田文懐九州大学, 工学部, 助手 (50223631) 堀田善治九州大学, 工学部, 助教授 (20173643)
Keywords	ECAP / ECAE / 超塑性 / 微細粒 / 靭性 / TEM / Al合金 / 強度
Research Abstract	ECAP(Equal Channel Angular Pressing)法とは,ある角度で交わる同じ径の溝をもつ金型を通して材料を強制的に押し出し,溝の交差面で強いせん断変形を与えると同時に結晶粒径を微細化する方法で,これによれば材料の大きさは加工の前後で変わらず,環境からの汚染もなく,孔のないバルク状態の超微細結晶粒材料が得られる.適用できる材料に原理的に制約がなく,従来の材料の組成を変えることなく特性を飛躍的に向上できる可能性がある.純Alについて歪の各段階での組織を電子顕微鏡で観察した結果,結晶粒の微細化は動的再結晶により起こること,せん断方向の組み合わせにより形成される組織が異なり,結晶粒の微細化には最適条件があることなどが明らかとなった.形成される微細粒の粒界は準安定状態で,移動抑制粒子がない場合には容易に粒界移動を起こした.Al-MgおよびAl-Mg-Li-Zr系合金での実験によれば,硬度は結晶粒径の-1/2乗に比例して増加し,いわゆるホール・ペッチの関係が成立する.673KでECAPしたAl-Mg-Li-Zr合金を603Kで引張変形すると,3.3×10^<-3>S^<-1>の歪速度で500%を超える超塑性伸びが観測され,3.3×10^<-2>S^<-1>の早い歪速度でも300%の伸びが得られた.この合金はECAP後に溶体化処理・時効すると強度が大幅に上昇し,かつ高い延性が保たれ,ECAP法が材料の靭性改善にもきわめて有効であることが示された.現在,ECAPによる超微細粒組織の形成機構の解析,Cu合金,Mg合金,Zn合金なども含めて組織の最適化条件の探索を進めると同時に,これらの材料の力学特性評価を継続して進めている.

Research Products
(13 results)

All Other

All Publications (13 results)

[Publications] Y.Iwahashi: "Principles of Equal-Channel Angular Pressing for the Processing of Ultra-Fine Grained Materials" Scripta Materialia. 35-2. 143-146 (1996)
[Publications] Y.Ma: "Significance of Microstructural Control for Superplastic Deformation and Forming" Materials Transactions JIM. 37・3. 336-339 (1996)
[Publications] M.Furukawa: "Structural Evolution and Validity of Hall-Petch Relationship in an Al-3%Mg Alloy with Submicron Grain Size" Materials Science Forum. 204-206. 431-436 (1996)
[Publications] J.Wang: "An Investigation of Microstructural Stability in an Al-Mg Alloy with Submicrometer Grain Size" Acta metallurgica et materialia. 44・7. 2973-2982 (1996)
[Publications] Z.Horita: "An Investigation of Grain Boundaries in Submicrometer-grained Al-Mg Solid Solution Alloy using High-resolution Electron Microscopy" Journal of Matererials Research. 11・8. 1880-1890 (1996)
[Publications] M.Furukawa: "Microhardness Measurements and the Hall-Petch Relationship in an Al-Mg Alloy with Submicrometer Grain Size" Acta metallurgica et materialia. 44・11. 4619-4629 (1996)
[Publications] P.Berbon: "An Investigation of the Properties of an Al-Mg-Li-Zr Alloy after Equal-Channel-Angular Pressing" Materials Science Forum. 217・222. 1013-1018 (1996)
[Publications] M.Furukawa: "Fablication of Submicrometer-Grained Zn-22%Al by Torsion Straining" Journal of Matererials Research. 11・9. 2128-2130 (1996)
[Publications] Z.Horita: "High-Resolution Electron Microscopy Study of Submicrometer-Grained Al-Mg Solid Solution Alloys" Proceedings of Microscopy and Microanalysis 1996. 524-525 (1996)
[Publications] Z.Horita: "Effect of Annealing on Grain Boundary Structure in Submicrometer-Grained Al-3%Mg Alloy Observed by High-Resolution Electron Microscopy" Annales de Chimie de France. 21. 417-425 (1996)
[Publications] M.Furukawa: "The Significance of the Hall-Petch Relationship in Ultra-Fine Grained Materials" Annales de Chimie de France. 21. 493-502 (1996)
[Publications] J.Wang: "Enhaced Grain Growth in an Al-Mg Alloy with Ultrafine Grain Size" Materials Science and Engineering A. 216. 41-46 (1996)
[Publications] M.Furukawa: "Production of Ultrafine-grained Metallic Materials Using an Intense Plastic Straining Technique" Proc.Int.Symp.on Interface Science and Materials Interconnection,JIM. (印刷中). (1996)

1996 Fiscal Year Annual Research Report

ECAP法による超微細粒合金の組織と力学特性

Principal Investigator

根本 実 九州大学, 工学部, 教授 (90005265)

Research Products

[Publications] Y.Iwahashi: "Principles of Equal-Channel Angular Pressing for the Processing of Ultra-Fine Grained Materials" Scripta Materialia. 35-2. 143-146 (1996)

[Publications] Y.Ma: "Significance of Microstructural Control for Superplastic Deformation and Forming" Materials Transactions JIM. 37・3. 336-339 (1996)

[Publications] M.Furukawa: "Structural Evolution and Validity of Hall-Petch Relationship in an Al-3%Mg Alloy with Submicron Grain Size" Materials Science Forum. 204-206. 431-436 (1996)

[Publications] J.Wang: "An Investigation of Microstructural Stability in an Al-Mg Alloy with Submicrometer Grain Size" Acta metallurgica et materialia. 44・7. 2973-2982 (1996)

[Publications] Z.Horita: "An Investigation of Grain Boundaries in Submicrometer-grained Al-Mg Solid Solution Alloy using High-resolution Electron Microscopy" Journal of Matererials Research. 11・8. 1880-1890 (1996)

[Publications] M.Furukawa: "Microhardness Measurements and the Hall-Petch Relationship in an Al-Mg Alloy with Submicrometer Grain Size" Acta metallurgica et materialia. 44・11. 4619-4629 (1996)

[Publications] P.Berbon: "An Investigation of the Properties of an Al-Mg-Li-Zr Alloy after Equal-Channel-Angular Pressing" Materials Science Forum. 217・222. 1013-1018 (1996)

[Publications] M.Furukawa: "Fablication of Submicrometer-Grained Zn-22%Al by Torsion Straining" Journal of Matererials Research. 11・9. 2128-2130 (1996)

[Publications] Z.Horita: "High-Resolution Electron Microscopy Study of Submicrometer-Grained Al-Mg Solid Solution Alloys" Proceedings of Microscopy and Microanalysis 1996. 524-525 (1996)

[Publications] Z.Horita: "Effect of Annealing on Grain Boundary Structure in Submicrometer-Grained Al-3%Mg Alloy Observed by High-Resolution Electron Microscopy" Annales de Chimie de France. 21. 417-425 (1996)

[Publications] M.Furukawa: "The Significance of the Hall-Petch Relationship in Ultra-Fine Grained Materials" Annales de Chimie de France. 21. 493-502 (1996)

[Publications] J.Wang: "Enhaced Grain Growth in an Al-Mg Alloy with Ultrafine Grain Size" Materials Science and Engineering A. 216. 41-46 (1996)

[Publications] M.Furukawa: "Production of Ultrafine-grained Metallic Materials Using an Intense Plastic Straining Technique" Proc.Int.Symp.on Interface Science and Materials Interconnection,JIM. (印刷中). (1996)

根本実九州大学, 工学部, 教授 (90005265)