| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 810944 | Journal of the Mechanical Behavior of Biomedical Materials | 2012 | 8 Pages |
The purpose of this work is to study the elastoplastic properties of novel intermetallic coatings grown by hot dipping on medical steel 316 LVM and their correlation with the scratch resistance by means of instrumented ultramicroindentation techniques. Elastoplastic properties are defined by the plasticity index (PI), which correlates the hardness and the Young's modulus, and the yield strength that delimits the elastic–plastic transition. To avoid overestimations of the PI due to the so-called indentation size effect, macroscopic hardness values were determined. The PI of the coating increases from 0.6 to 0.8 with increasing immersion time. These values are always lower than those of the bare substrate (0.9) but higher than those found for ceramics (∼0.5). The increase of the PI is accompanied by a decrease in the yield strength from 0.73 to 0.34 GPa, which highlights the relevance of the compressive residual stresses and their relaxation with increasing immersion time. The higher plasticity is shown by higher apparent friction coefficients (0.159), which are always lower than those of the bare steel (0.264). Therefore, these intermetallic coatings could be considered “hard but tough” coatings, suitable for enhancing the wear resistance of the medical steel, especially when using short periods of immersion. The study provides evidence that the load–depth curve of indentation contains abundant information and that its analysis can be used to determine various mechanical properties of coatings that could be important for load bearing components.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (366 K)Download as PowerPoint slideHighlights► Hot dipping of 316 L medical steel in Al–Si alloys develops intermetallic coatings. ► Plasticity index of the coating increases with increasing the immersion time. ► Yield strength of the coating decreases with increasing the immersion time. ► Elastoplastic behavior of the coating correlates with the level of residual stresses. ► The higher plasticity is manifested by higher apparent friction coefficients.
