Mechanical properties of Al-based amorphous/nanocrystalline alloys

The present work deals with testing of mechanical properties of Al87Ni7Nd6 and Al88Fe9Nd3 alloys rapidly quenched in the form of ribbons, having completely and partially amorphous microstructure respectively. Al87Ni7Nd6 Amorphous alloys show three transformation events the first of which involves the formation of Al nanocrystals dispersed in the amorphous phase. The micro-hardness of samples annealed at different devitrification stages was determined. An increment in hardness from 250 HVN (as quenched samples) to 355 HVN (nanocrystalline samples) was observed. The amorphous samples were cold-rolled up to 10% elongation without formation of cracks. Shear bands were evident on the outer surface. Al88Fe9Nd3 nanocrystalline samples were cold-rolled up to 2% of elongation but cracks were detected. Tensile fracture surfaces showed dimples with diameter of the order of a hundred nanometers and no vein patterns are observed.