Properties of Ni-based amorphous ribbons consolidated by high pressure torsion

Two amorphous ribbons, of compositions (Ni56Cu2)Zr18Ti16Al3Si5 and (Ni36Cu23)Zr18Ti14Al5Si4, were subdued to the similar process of cold consolidation by the high pressure torsion (HPT) method. The first ribbon, that revealed higher thermal stability of the amorphous phase, higher GFA and better mechanical properties like tensile strength, Young modulus and hardness, partially crystallized in the HPT process. The second ribbon, revealing lower Tg and Tx temperatures, tensile strength and hardness, could be consolidated preserving amorphous structure. Such result suggests that the thermal stability against crystallization was not responsible for the preservation of the amorphous phase in the cold consolidation by the HPT. It rather seemed that a proper relation of the undercooled liquid temperature range to the local temperature increase during consolidation is suggested and it was a decisive parameter