한국주조공학회

In the present study, the microstructural evolution and mechanical properties o f A l71.6Ge28.4 eutectic alloy have been investigated. Stable (fee a-A l and diamond cubic P-Ge) and various metastable crystalline (monoclinic, rhombohedral) phases were produced by competitive phase selection during non-equilibrium processing methods i.e. melt spinning and injection casting. The as-injection casted samples containing metastable-equilibrium eutectic (a-Al + monoclinic) structure showed much higher strength than samples with equilibrium eutectic (a-Al + P-Ge) structure but plasticity disappointingly diminished. In order to endow the enhanced ductility without significant strength drop, the alloys was heat-treated at transition temperature from metastable phase to stable phase. The annealed specimen displayed the phase transformed microstructural evolution and enhanced macroscopic plasticity.

Al-Ge eutectic alloy, Non-equilibrium processing, Metastable phase, Strength, Plasticity, Annealing.