Dispersion of the Structure in Al-Based Alloys by Different Methods of Severe Plastic Deformation

Abstract

Structural and phase transformations in V95 (type of A7075) alloy upon high pressure torsion (HPT) up to high strain and upon dynamic channel angular pressing (DCAP) were studied using electron microscopy (TEM, SEM) and x-rays diffraction. It was established that the nanostructure with average grain size of 80-55 nm and hardness value of 2.5 GPa is formed by HPT at strain of e=5.5-6.4. It was shown the hardening metastable phase MgZn2 precipitates from supersaturated α-solid solution during dynamic deformation aging; its quantity grows with increasing of strain. Ultra fine grained structure with high- angle boundaries is formed in V95 alloy after already 2 cycles of DCAP. The average grain size is 200 nm in DCAP samples.