Enthalpy relaxation behaviour of Al-Si-Cr quasicrystalline and amorphous alloys upon annealing

A. Inoue, A. P. Tsai, H. M. Kimura, T. Masumoto

    Research output: Contribution to journalArticlepeer-review

    9 Citations (Scopus)


    Annealing-induced enthalpy relaxation behaviour was examined calorimetrically in quasicrystalline Al62Si19Cr19 and amorphous Al60Si25Cr15 alloys. When both alloys annealed at temperatures below Tx are reheated, an excess endothermic reaction (enthalpy relaxation) occurs reversibly above the annealing temperature, Ta. The peak temperature of ΔCp,endo rises in a continuous manner with the logarithm of annealing time (ta). The magnitudes of ΔCp,endo and ΔHendo of the amorphous alloy increase with increasing Ta while no appreciable change in ΔCp,endo and ΔHendo of the quasicrystal with Ta is seen. The activation energy, Qm, for the enthalpy relaxation increases from 1.8 to 2.7 eV with the peak temperature of ΔCpTm, for the amorphous alloy, whereas it remains constant (≅1.3 eV) for the quasicrystal. The endothermic reaction with small Om for the quasicrystal is thought to be attributable to the disappearance of short-range ordering of chromium and silicon atoms with stronger attractive interaction, which developed during annealing, i.e. the reversion phenomenon, in the unrelaxed localized regions with high free-energy isolately embedded in the more stable icosahedral structure. The similarity of the enthalpy relaxation behaviour between the quasicrystalline and amorphous phases allows us to infer that short-range atomic configuration is very similar between the quasicrystalline and amorphous phases.

    Original languageEnglish
    Pages (from-to)429-437
    Number of pages9
    JournalJournal of Materials Science
    Issue number2
    Publication statusPublished - 1988 Feb 1

    ASJC Scopus subject areas

    • Materials Science(all)
    • Mechanics of Materials
    • Mechanical Engineering


    Dive into the research topics of 'Enthalpy relaxation behaviour of Al-Si-Cr quasicrystalline and amorphous alloys upon annealing'. Together they form a unique fingerprint.

    Cite this