Phase equilibria and Heusler phase stability in the Cu-rich portion of the Cu-Al-Mn system

R. Kainuma, N. Satoh, X. J. Liu, I. Ohnuma, K. Ishida

Research output: Contribution to journalArticlepeer-review

139 Citations (Scopus)

Abstract

Results pertaining to the phase equilibria between the phases α (A1), β (A2, B2 or L21 (D03)) and γ (γ-bronze type), and the two-stage order-disorder transition and decomposition reaction A2-B2-L21 in the ternary system Cu-Al-Mn are reported. Ternary isothermal section diagrams at 800, 700, 600 and 550°C have been constructed using Energy Dispersion X-ray Spectrometry (EDX) analysis results, and it is found that the β single-phase region in the Cu-Al system is very significantly widened on increasing the Mn content. The critical temperatures (Tc) of the A2-B2-L21 order-disorder transitions, determined by Differential Scanning Carolimetory (DSC) analysis are found to be strongly dependent on the Al content rather than on the Mn content. It is confirmed by DSC measurements and TEM-EDX analysis that a miscibility gap island between Cu3Al and Cu2AlMn phases exists in the L21 phase region. The second order ordering reaction between D03 and L21 structures has also been detected by X-ray diffraction. The stability of the bcc β phase is discussed in terms of atomic and magnetic ordering.

Original languageEnglish
Pages (from-to)191-200
Number of pages10
JournalJournal of Alloys and Compounds
Volume266
Issue number1-2
DOIs
Publication statusPublished - 1998 Feb 20

Keywords

  • Heusler alloy
  • Magnetic transformation
  • Miscibility gap island
  • Order-disorder transition
  • Phase equilibria

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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