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Phase Decomposition of Heat Resistant Magnesium Alloys Containing Heavy Rare Earth Elements and Its Control

Research Project

Project/Area Number 07455257
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Physical properties of metals
Research InstitutionNagaoka University of Technology

Principal Investigator

KOJIMA Yo  Department of Mechanical Engineering Nagaoka University of Technology, Professor, 工学部, 教授 (60016368)

Co-Investigator(Kenkyū-buntansha) KAMADO Shigeharu  Department of Mechanical Engineering Nagaoka University of Technology, Associate, 工学部, 助教授 (30152846)
Project Period (FY) 1995 – 1996
Project Status Completed (Fiscal Year 1996)
Budget Amount *help
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 1996: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1995: ¥6,900,000 (Direct Cost: ¥6,900,000)
KeywordsMagnesium Alloy / Rare Earth Containing Alloy / Phase Diagram / Aging Characteristics / Hot Workability / Microstructural Control / Corrosion Resistance / High Temperature Tensile Property / ミクロ組織
Research Abstract

The aim of this study is to develop a new magnesium alloy which has more excellent heat and corrosion resistance than that of the conventional heat resistant aluminum and magnesium alloys that could be applicable to piston and other engine parts undergoing the highest thermal load among automobile parts. The Mg-rich portion of phase diagrams, aging characteristics, hot workability, corrosion behavior and microstructural control of magnesium alloys containing heavy rare earth elements were investigated. Finally, the alloys were hot-forged into a piston shape and their tensile properties were also evaluated. (1) The solid solubilities of heavy rare earth elements in magnesium shift largely to lower concentrations than those of Mg-Gd or -Dy binary alloys by Nd or Y addition with decreasing temperature. As a result, alloys containing Gd or Dy of more than 6% and Nd or Y of more than 3% show marked age hardening even at 250゚C and have higher tensile strength than the conventional magnesium … More alloys. (2) The precipitation sequences of the investigated alloys are as follows : Magnesium supersaturated solid solution* beta" (DO_<19>) *beta' (bco) *Equilibrium beta (Nd containing alloy : fcc, Y containing alloy : bcc). The remarkable age hardening is caused by the precipitation of metastable beta"-phase. The beta"-phase precipitate preferentially on the dislocations introduced by the hot rolling or hot forging and, therefore, precipitation free zone near the grain boundaries is reduced. As a result, tensile properties are enhanced by the hot working. (3) It is possible for the investigated alloys to suppress grain coarsening and to reduce the amount of remained eutectic compound by lowering the homogenizing temperature to just above the solubility limit and, therefore, to directly dieforge all specimens into a piston shape without an intermediate upset forging. Die-forged Mg-10%Gd-3%Y alloys exhibits a tensile strength of 290MPa and 0.2% proof stress of 250MPa at 250゚C,which are superior to those of the conventional heat resistant magnesium alloys and are more than double those of the conventional heat resistant aluminum alloys. (4) A fine Mg (OH)_2 layr is formed as the stable protective film on the surface of all investigated alloys by the additions of rare earth elements under a corrosive environment containing a chloric ion. Less

Report

(3 results)
  • 1996 Annual Research Report   Final Research Report Summary
  • 1995 Annual Research Report
  • Research Products

    (18 results)

All Other

All Publications (18 results)

  • [Publications] 桐生雅夫,奥村勇人,鎌土重晴,小島陽,二宮隆二,中津川勲: "重希土類元素を含む耐熱マグネシウム合金の耐食性" 軽金属. 46. 39-44 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] S. Kamado, Y. Kojima, T. Nishimura, R. Ninomiya and K. Kubota: "Aging Characteristics and Mechanical Properties of Heat-Resistant Magnesium Alloys Containing Heavy Rare Earth Metals" Proceedings of the International Symposium of Recent Metallurgical Advances in Light Metals Industries. 229-242 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Y. Kojima and S. Kamado: "New Magnesium Alloys with High Tensile Strength at High Temperature can be Hot Forged" Materials Technology. 11. 45-47 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] S. Kamado and Y. Kojima: "Ageing Characteristics and high temperature tensile properties of magnesium alloys containing heavy rare earth elements" Proceedings of 3rd International Magnesium Conference. 327-342 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] I. Nakatsugawa, S. Kamado, Y. Kojima, R. Ninomiya and K. Kubota: "Corrosion behaviour of magnesium alloys containing heavy rare earth elements" Proceedings of 3rd International Magnesium Conference. 687-698 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 谷池茂弘,北口豊,鎌土重晴,小島陽,関伊佐夫,久保田耕平: "Mg-重希土類元素合金の鍛造性および鍛造材の時効特性と引張特性" 軽金属. 47(印刷中). (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] M.Kiryuu, H.Okumura, S.Kamado, Y.Kojima, R.Ninomiya and I.Nakatsugawa: "Corrsion Resistance of Heat Resistant Magnesium Alloys Containing Heavy Rare Earth Elements" Journal of Japan Institute of Light Metals. Vol.46. 39-44 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] S.Kamado, Y.Kojima, T.Nishimura, R.Ninomiya and K.Kubota: "Aging Characteristics and Mechanical Properties of Heat-Resistant Magnesium Alloys Containing Heavy Rare Earth Metals" Proceedings of the International Symposium of Recent Metallurgical Advances in Light Metals Industries. 229-242 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Y.Kojima and S.Kamado: "New Magnesium Alloys with High Tensile Strength at High Temperature can be Hot Forged" Materials Technology. Vol.11. 45-47 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] S.Kamado and Y.Kojima: "Ageing Characteristics and High Temperature Tensile Properties of Magnesium Alloys Containing Heavy Rare Earth Elements" Proceedings of 3rd International Magnesium Conference. 327-342 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] I.Nakatsugawa, S.Kamado, Y.Kojima, R.Ninomiya and K.Kubota: "Corrosion Behavior of Magnesium Alloys Containing Heavy Rare Earth Elements" Proceedings of 3rd International Magnesium Conference. 687-698 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] S.Taniike, Y.Kitaguchi, S.Kamado, Y.Kojima, I.Seki and K.Kubota: "Forgeability of Mg-Heavy Rare Earth Metal Alloys, and Aging Characteristics and Tensile Properties of Their Forged Materials" Journal of Japan Institute of Light Metals. Vol.47 (in press). (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 桐生雅夫,奥村勇人,鎌土重晴,小島陽,二宮隆二,中津川勲: "重希土類元素を含む耐熱マグネシウム合金の耐食性" 軽金属. 46・1. 39-44 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] S.Kamado,Y.Kojima,T.Nishimura,R.Ninomiya and K.Kubota: "Aging Characteristics and Mechanical Properties of Heat-Resistant Magnesium AlloysContaining Heavy Rare Earth Metals" Proceedings of the International Symposium of Recent Metallurgical Advances in Light Metals Industries. 229-242 (1995)

    • Related Report
      1996 Annual Research Report
  • [Publications] Y.Kojima and S.Kamado: "New Magnesium Alloys with High Tensile Strength at High Temperature can be Hot Forged" Materials Technology. 11・2. 45-47 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] S.Kamado and Y.Kojima: "Ageing characteristics and high temperature tensile properties of magnesium alloys containing heavy rare earth elements" Proceedings of 3rd International Magnesium Conference. 327-342 (1997)

    • Related Report
      1996 Annual Research Report
  • [Publications] I.Nakatsugawa,S.Kamado,Y.Kojima,R.Ninomiya and K.Kubota: "Corrosion behaviour of magnesium alloys containing heavy rare earth elements" Proceedings of 3rd International Magnesium Conference. 687-698 (1997)

    • Related Report
      1996 Annual Research Report
  • [Publications] 谷池茂弘,北口豊,鎌土重晴,小島陽,関伊佐夫,久保田耕平: "Mg-重希土類元素合金の鍛造性および鍛造材の時効特性と引張特性" 軽金属. 47・4(印刷中). (1997)

    • Related Report
      1996 Annual Research Report

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Published: 1995-04-01   Modified: 2016-04-21  

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