Investigating size-dependent strengthening and deformation in Ni-based alloy GH3535 single-crystal micropillars

Abstract

The properties of single crystal GH3535, a solid-solution strengthened Ni-based superalloy have been investigated in compression using micropillars with diameters ranging from 1000 to 3300 nm. Micropillars were fabricated from an EBSD identified [001]-oriented grain using a gallium focused ion beam (Ga-FIB), enabling the determination of resolved shear stress (RSS) on [111] glide planes. The GH3535 pillars exhibit a pronounced size effect, with strength increasing as the pillar size decreases, following a power-law relation with an exponent of -0.67. Deformation was primarily governed by the activation of the {111}<101> slip system, as evidenced by sharply defined slip traces and multiple parallel and non-parallel slip bands observed after compression. The observed size effect was compared with literature data for other Ni-based superalloys and for pure Ni, which serves as a reference for single-element face-centered cubic (fcc) metals. This measured size exponent aligns with the empirical trend observed in fcc metals, confirming that GH3535 material retains the fundamental sizedependent strengthening behavior of fcc materials.