Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1574098 | Materials Science and Engineering: A | 2015 | 11 Pages |
Abstract
This paper explores the indentation size effect (ISE) in pack carbo-nitrided AISI 8620 steel surfaces. The surfaces of the AISI 8620 steel samples were pack carbo-nitrided at 900 °C using cyanide-containing dried cassava leaves (bio-processed waste). This was achieved by quenching in different pH levels of cyanide-based bio-processed solution (BPS). Nanoindentation was carried out (using a Berkovich tip) on the surface modified steels. This was used to measure the hardness and reduced elastic moduli of the quenched-carbonitrided and the as-received steel surfaces. The surface-modified steel was shown to have higher hardness than the as-received steel. The hardness was also found to depend strongly on the indentation size. The paper also considers the potential contributions from microstructure, geometrically necessary dislocations (GNDs) and C/N diffusion on the measured hardness values. However, the measured ISEs are attributed largely to the role of GNDs that are modeled using the Nix and Gao mechanism-based strain gradient plasticity model. The implications of the results are then discussed for the design of hard carbo-nitrided steel surfaces.
Keywords
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Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
E.K. Arthur, E. Ampaw, M.G. Zebaze Kana, K.J. Akinluwade, A.R. Adetunji, O.O. Adewoye, W.O. Soboyejo,