Effects of pre-straining and coating on plastic deformation of aluminum micropillars

摘要: Abstract The plastic deformation of micropillars is known to be affected by whether dislocations can escape easily from the material volume, and extent which mutually interact during deformation. In this work, pre-straining coating are used modify initial dislocation content constraints on dislocations. Aluminum in size range ∼1 ∼6 μm, with or without thin tungsten deposition 7%, were compressed using a flat-punch nanoindenter study their plasticity behavior. results reveal very different behavior between regime few microns that ∼1 μm. For pillars large, leads significant strengthening, 7% also produces mild strengthening effect. proof strength exhibits good correlation square root residual density measured transmission electron microscopy after deformation, indicating controlled interactions as traditional Taylor hardening. Coating evidently helps retain inside pillar, increases content; both effects lead more severe strain hardening smaller ∼1 μm size, however, softening, although still no density, remains close value even coating. These suggest starvation small availability mobile cannot effectively trap but strengthen presumably because nucleation difficult at coated surface.