High pressure induced crystallization of rapidly solidified Al-Fe and Al-Mn quasi-crystalline alloys

Abstract

The presence of phases showing icosahedral point symmetry was reported by Shechtman, Blech, Gratias and Cahn in rapidly quenched alloys of Al-Mn, Al-Fe and Al-Cr, and subsequently many other splat-cooled alloys with the i phase have been reported. In this paper we present the first results of high pressure experiments carried out on Al-Fe and Al-Mn quasi-crystals. The experiments performed at room temperature showed irreversible quasi-crystal-to-crystal transitions in Al?Mn and Al?Fe alloys. The transition pressures are 49 kbar for Al₇₈Mn₂₂, 93 kbar for Al₈₆Mn₁₄, 79 kbar for Al₈₆Fe₁₄, 54 kbar for Al₈₂Fe₁₈ and 108 kbar for Al₇₅Fe₂₅. The high pressure phases are found to be the equilibrium phases.