Size Effects in Strength and Strain Hardening Behavior of Single-Crystal 7075 Aluminum Alloy Micropillars

The article investigates the size effects on strength and strain hardening behavior of single-crystal 7075 Aluminum Alloy micropillars. It highlights the distinctive deformation mechanisms at reduced scales, including size-dependent flow stress and plastic instability. The study introduces high-density second-phase nano-particles through heat treatment and examines their effects on deformation and strain hardening behaviors. The results show that the presence of precipitates significantly enhances plasticity and strain hardening capabilities, virtually eliminating the size effect. The article also discusses the origin of the non-size effect in 7075 Al alloy, attributing it to the strengthening effect of precipitates and the increased pinning points for dislocation sources. The study concludes that the introduction of dense nano-precipitates offers advantages for the application of micro- and nano-sized components in advanced engineering systems.