1,720,995 research outputs found
Size effects in nanoindentation of hard and soft surfaces
No full textNanoindentation experiments carried out with atomic force microscopes (AFMs) open the way to understand size-related mechanical effects that are not present at the macro- or micro-scale. Several issues, currently the subject of a wide and open debate, must be carefully considered in order to measure quantities and retrieve trends genuinely associated with the material behaviour. The shape of the nanoindenter (the AFM tip) is crucial for a correct data analysis; we have recently developed a simple geometrical model to properly describe the tip effect in the nanoindentation process. Here, we demonstrate that this model is valid in indentation of both soft and hard, or relatively hard, materials carried out by two distinct, commercially available, AFM probes. Moreover, we implement the model with a data interpretation approach aimed at preventing underestimation of the tip penetration into the material. Experiments on soft polymeric materials (poly(methyl methacrylate) and polystyrene) and hard or relatively hard (Si, Au, Al) materials are reported. The results demonstrate that true hardness data can be attained also in shallow indentations and that the appearance of size effects strongly depends on data interpretation issues. In addition, we report on stiffness data measured on the considered materials during their nanoindentation
An AFM Tip Model for Investigating the Mechanical Properties of Materials at the Nanoscale
No full textInvestigation of the mechanical properties of materials at the nanoscale is often performed by atomic force microscopy nanoindentation. However, substrates with large surface roughness and heterogeneity demand careful data analysis. This requirement is even more stringent when surface indentations with a typical depth of a few nanometers are produced to test material hardness. Accordingly, we developed a geometrical model of the nanoindenter, which was first validated by measurements on a reference gold sample. Then we used this technique to investigate the mechanical properties of a coating layer made of Balinit C, a commercially available alloy with superior anti-wear features deposited on steel. The reported results support the feasibility of reliable hardness measurements with truly nanosized indents
An Atomic Force Microscopy Tip Model for Investigating the Mechanical Properties of Materials at the Nanoscale
No full textInvestigation of the mechanical properties of materials at the nanoscale is often performed by atomic force microscopy nanoindentation. However, substrates with large surface roughness and heterogeneity demand careful data analysis. This requirement is even more stringent when surface indentations with a typical depth of a few nanometers are produced to test material hardness. Accordingly, we developed a geometrical model of the nanoindenter, which was first validated by measurements on a reference gold sample. Then we used this technique to investigate the mechanical properties of a coating layer made of Balinit C, a commercially available alloy with superior anti-wear features deposited on steel. The reported results support the feasibility of reliable hardness measurements with truly nanosized indents
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