Influence of heating on structure and mechanical characteristics of amorphous Al86Ni9Gd5 ribbons

Abstract

Changes of structure and mechanical characteristics of amorphous Al86Ni9Gd5 melt-spun ribbons subjected to linear heating at a rate of 10 K/min were investigated by differential scanning calorimetry, X-ray diffraction, transmission electron microscopy, three-point bending testing and microhardness measurements. Non-monotonic changes of all mechanical characteristics were related to the structural variations occurring at three-stage transformation process. It was established that nanocrystallization of amorphous phase led to drop of all properties measured by three-point bend testing (the modulus of elasticity, bending limit at fracture and plasticity) while formation of the intermetallic compounds and coarsening of structure during subsequent transformation stages resulted in their partial recovery. On the contrary, microhardness had a maximum (about 4.5 GPa) in the samples with the ultra-fine grained partially crystallized structure. The potential for practical applications of the established effect of recovery of plasticity from zero in nanocomposite structure to about 1% in the fully crystallized sample with microhardness about 3 GPa was discussed.