Mechanical properties of Al based amorphous and devitrified alloys containing different rare earth elements

Abstract

Mechanical properties of Al 87Ni 7RE 6 amorphous and devitrified alloys (RE = Ce, Nd, La) are reported in this work. The microhardness of samples annealed at different devitrification stages is determined and an improvement is observed for all compositions when Al nanocrystals are present in the amorphous matrix. A further increase is found after a second transformation due to precipitation of an unknown phase in Al 87Ni 7Nd 6. The fracture surfaces resulting from tensile tests of amorphous samples are examined both with scanning electron microscopy and transmission electron microscopy, where shear bands, vein patterns and protrusion are seen. There is no sign of crystallisation in shear bands and in vein patterns although their shape suggests a rise in temperature during deformation. Also in cold rolled samples the crystallization is avoided during deformation.