Indentation Size Effects in the Nano and Microhardness of FCC Single Crystal Metals

Abstract

This paper presents the results of the experimental study of nano and micro indentation size effect on selected (001) oriented face centered cubic (FCC) crystals (Ni, Au, and Ag). Following a detailed description of experimental techniques and correction factors, indentation size effects in (001) oriented Au, Ag, and Ni single crystals are elucidated. Material pile-up phenomena are discussed before analyzing the results within the context of mechanism-based strain gradient plasticity (SGP) theories. Microstructure length scales are calculated based on the analysis. These are shown to vary with indentation size. A bi-linear behavior is shown to describe the indentation size effects between the micro-and nano-scales. This is rationalized by considering the limiting cases of plastic deformation by source-limited and established dislocation substructures. A multi-scale framework is proposed for modeling small contacts.

Indentation size effects in face centered cubic single crystal thin films

“…Three distinct pile-up lobes were also observed around the sides of the triangular cross-sections resulting from Berkovich indentations. Similar results were also obtained in a more recent study by Zong et al [25] on (0 0 1) oriented Ni, Au and Ag single crystals. This paper presents the results of an experimental study of contact-induced deformation in (0 0 1), (0 1 1) and (1 1 1)-oriented Au, Ag and Ni single crystals.…”

Indentation size effects in pack carbo-nitrided AISI 8620 steels

“…The results are also compared with prior measurements (of hardness versus indentation depth) by Rodriguez and Gutierrez [25] for alloyed steel. Similar indentation size effects have been reported for both single crystalline [12,23,24] and polycrystalline [38,39] metals in the nano-and micro-scale regimes. Fig.…”

“…Hence, the measured changes in hardness are attributed to effects of strain gradients that give rise to the formation of geometrically necessary dislocations that are the causes of the ISE [22]. The measured ISE was interpreted using the mechanism-based strain gradient plasticity theory of Nix and Gao [22][23][24][25][26][27][28]. The implications of the results are then discussed for the carbo-nitriding of steel surfaces for a range of structural and tribological applications.…”

“…The phenomenon is usually attributed to causes such as work hardening, pile-up, sinkin, roughness, surface energy, crystal anisotropy and the shape of the indenter [21,22]. Zong et al [23,24] have also studied ISE in both single and polycrystalline Au, while Cao et al [13] have studied the indentation size effects in polycrystalline Au and Ag thin films. Rodriguez and Gutierrez [25] have investigated the ISE in several heat treated steels.…”

Influence of strain gradients on lattice rotation in nano-indentation experiments: A numerical study

“…Strain-gradient plasticity theories [12][13][14][15][16] that account for the effects of geometrically necessary dislocations (GNDs) [17] on plastic flow had some success in explaining size effects observed in torsion [18], bending [19] and indentation [20][21][22]. In this paper, a 3D non-local elastic-viscoplastic crystalplasticity finite-element model for the nano-indentation of Ti-15V-3Al-3Sn-3Cr…”