PLASTIC-DEFORMATION IN ALCUFE ICOSAHEDRAL PHASE

Plastic deformation of icosahedral AlCuFe has been studied by compression tests for temperatures ranging from room temperature to 750-degrees-C. Whereas at room temperature no ductility is observed, the samples can be homogeneously deformed up to 130% at high temperatures with no final hardening stage. SEM observations reveal, at the ultimate stage of deformation, a vein pattern similar to that observed in amorphous metals but without slip bands or shear bands. Stress relaxation measurements show two different regimes at low and high temperatures with a transition at 660-degrees-C. It is concluded from these experiments that dislocations are probably not responsible for the plastic deformation of icosahedral quasicrystals.