Regensburg 2002 – wissenschaftliches Programm

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M: Metallphysik

M 10: Quasikristalle III

M 10.2: Fachvortrag

Dienstag, 12. März 2002, 14:45–15:00, H6

Solid state reaction of high strength Al-composites with complex quasicrystalline and intermetallic phases — •Frank Schurack, Jürgen Eckert, and Ludwig Schultz — IFW Dresden, Institut für Metallische Werkstoffe, PF 270016, 01171 Dresden

We investigate the phase formation in Al-Mn-Ce/Fe and Al-Cu-Fe alloys as representative examples for the existence of thermodynamically metastable and stable quasicrystalline (qc) phases, respectively. Samples were prepared via solid state reaction using mechanical alloying and ball milling of arc-melted ingots. We report on the phase transformation reactions upon preparation and during annealing treatment leading to a composite microstructure of Al-matrix, crystalline intermetallic phases and qc-phase. For Al-Mn-Ce/Fe alloys the actual phase composition of the composite is a function of the processing conditions. The existence of a stable qc-phase in Al-Cu-Fe allows to influence the composite structure by stepwise reactions. Therefore, different stoichiometric reaction routes have been explored. Since the actual aim of the work is the synthesis of novel high strength Al-qc-composites the mechanical behaviour was characterized by constant rate compression tests. Ultimate strengths of up to σ_f= 977 MPa were reached at plastic strains of more than ε_pl= 10 %. As a function of the Al-content and the particle morphology the mechanical properties can be taylored in a wide range.