STRUCTURE EVOLUTION OF A ZIRCONIUM-BASED AMORPHOUS ALLOY UPON MEGAPLASTIC STRAIN IN THE BRIDGEMAN CHAMBER

摘要

The structure evolution of the Zr_(50)Ni_(18)Ti_(17)Cu_(15) massive metal glass upon megaplastic strain (MPS) in the Bridgeman chamber is investigated in a wide interval of strain degrees at room temperature. It is demonstrated that upon MPS with n = 1/2 rotation of the Bridgeman anvil, nanocrystalline phases are precipitated in the alloy. With increasing strain, these phases are dissolved. It is suggested that nucleation centers of nanocrystalline phases (nanoclusters) are formed in the amorphous matrix upon MPS under compression without shear in the Bridgeman chamber. These phases grow in the shear bands transforming into the nanocrystalline phase upon MPS.