• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to project page

1996 Fiscal Year Final Research Report Summary

Development of Light Weight-High Temperature Structural L1_2 Compounds in Al_3Ti-Base Alloys.

Research Project

Project/Area Number 07650822
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Structural/Functional materials
Research InstitutionOsaka Prefecture University

Principal Investigator

MABUCHI Hiroshi  Osaka Prefecture University, Coll Engn, Assoc Prof., 工学部, 助教授 (70109883)

Co-Investigator(Kenkyū-buntansha) TSUDA Hiroshi  Osaka Prefecture University, Coll Engn, Research Assoc., 工学部, 助手 (80217322)
Project Period (FY) 1995 – 1996
KeywordsLight weight heat-resistant material / Titanium trialuminide / Intermetallic compound / Crystal structure control / Equilibrium phase diagram / Ductility improvement / Oxidation resistance
Research Abstract

The intermetallic compound Al_3Ti is very attractive as a potential high-temperature structural material. Some of the positive characteristics of this compound are its good oxidation resistance, low density of 3.3 g cm^<-3>, and relatively high melting point of about 1673 K.However, it has the low-symmetry tetragonal D0_<22> structure and is brittle at room temperature. Successful development of this aluminide depends on whether we can overcome its brittleness at ambient temperature. One possible approach to ductilize ordered intermetallics with low-symmetry crystal structures is to change their structures to those of higher symmetry. Indeed, it is known that replacing a certain amount of aluminum atoms in Al_3Ti with Zn, Ni, Cu, or Fe changes the structure of Al_3Ti(D0_<22>) to the L1_2 structure. The authors found the formation of new ternary L1_2 compounds in Al_3Ti-base alloys containing Mn, Cr, Ag, Rh, Pt, and Au. Many studies on the Al-Ti-X (X=Ni, Fe, Cu, Mn, Cr, Ag and Pd etc.) … More alloys have focused on the mechanical properties of the ternary L1_2 trialuminide compounds. However, the ternary L1_2 compounds are still brittle in tension and/or bending, although they exhibit appreciable compressive ductility at ambient temperature.Recently, much work has been made of the microstructure, especially second phases and porosity generally induced by a homogenization treatment, and microstructure-mechanical property relationships of the ternary L1_2 trialuminide compounds. The present authors more recently reported also the effects of manganese on the microstructure and mechanical properties of ternary L1_2 intermetallic compounds in the Al_3Ti-based alloys, and that the titanium trialuminide containing Mn does posses some bend ductility at room temperature when porosity is reduced.
In the present study, sintering of elemental powders was carried out to form ternary L1_2 intermetallic compounds in Al-Ti-Cr alloys. The L1_2 phase field and equilibrium phases surrounding the L1_2 phase at 1423K have been established. Besides the L1_2 phase, the pertinent second phase fields have been also estimated ; TiAl, TiAl_2, Ti_2Al_5, Al_3Ti, Al_<17>Cr_9, AlCr_2, and TiAlCr phase fields. The vertical section of the Al-25mol%Ti-Cr alloys has been experimentally determined, and the presence of the L1_2+ Liquid phase field in the present composition and temperature ranges was confirmed. Button ingots of some ternary L1_2 compounds in the Al-Ti-Cr alloys were prepared by arc-melting to investigate their microstructure (especially second phases and porosity), microhardness, and bend ductility. In general, homogenization of as arc-melted alloys substantially reduced the amount of second phases but introduced extensive porosity. Therefore, the formation of porosity is closely associated with second phase solutionized during homogenization treatment. However, no residual porosity was observed in higher Cr content alloys. The porosity after homogenization was observed when Al_<17>Cr_9 phase is formed and not when TiAlCr or AlCr_2 phase is formed. The ternary L1_2 compounds in the Al-Ti-Cr alloys had some bend ductility at ambient temperature, which can be increased to about 0.9% (plastic bend strain) by increasing the Cr content when porosity is reduced. Less

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] H.Mabuchi: "Formation of Ternary Ll_2 Compounds in Al_3Ti-base Alloys." Intermetallics. 1-1. 41-48 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Mabuchi: "Compositional Effects on Formation and Properties of Ternary Ll_2 Compounds on Al_3Ti." Proc.3rd Japan Inter.SAMPE Symp.3-2. 1530-1535 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Mabuchi: "Combustion Synthesis of TiAl-matrix Composites in the Ti-Al-BN System." Scripta Metall.Mater.32-2. 253-257 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 間渕 博: "燃焼反応プロセスにより作製したTiAl-Ti_2AlC複合材料の組織と機械的性質" 紛体および粉末冶金. 42-11. 1289-1294 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Mabuchi: "Effects of Manganese on the Ll_2 Compound Formation in Al_3Ti-base Alloys." Intermetallics. 4-S. S193-S199 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 間渕 博: "Ll_2型Al_3Ti基合金の燃焼合成" 日本金属学会会報(まてりあ). 35-3. 673-641 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Mabuchi: "Formation of Ternary L1_2 Compounds in Al_3Ti-base Alloys." Intermetallics. 1-1. 41-48 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Mabuchi: "Compositional Effects on Formation and Properties of Ternary L1_2 Compounds on Al_3Ti." Proc.3rd Japan Inter.SAMPE Symp. 3-2. 1530-1535 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Mabuchi: "Combustion Synthesis of TiAl-matrix Composites in the Ti-Al-BN System." Scripta Metall.Mater. 32-2. 253-257 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Mabuchi: "Microstructure and Mechanical Properties of TiAl-Ti_2AlC Composites Produced by Combustion Reaction Process." J.Jpn.Soc.Powder Metall. 42-11. 1289-1294 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Mabuchi: "Effects of Manganese on the L1_2 Compound Formation in A1_3Ti-base Alloys." Intermetallics. 4-S. 193-199 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Mabuchi: "Combustion Synthesis of L12 Compounds in Al_3Ti-base Alloys." J.Inst.Jpn.Materia. 35-3. 673-641 (1996)

    • Description
      「研究成果報告書概要(欧文)」より

URL: 

Published: 1999-03-16  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi