Automatic Vickers hardness test by scratch tester

Hardness is a mechanical property that defines a material’s resistance to localized permanent deformation under a compressive force. Over the years, numerous methods of characterizing the hardness of different materials have been developed and improved. The standardized Vickers hardness test is one of the most widely used method to characterize the hardness of various types of materials.
The test relies on the concept of indentation hardness, in which a pyramidal diamond indenter of precisely defined geometry is pressed into the surface of the material under a specific load, usually ranging from a few grams to several kilograms. The imprint left by the diamond indenter is in the shape of a square-based pyramid with well-defined angles. The diagonals of the resulting imprint are measured using a microscope, and the hardness value is calculated based on the applied force and the surface area of the residual imprint. The resulting indentation size reflects the material's resistance to plastic deformation. For the same load, the imprint on the surface will be smaller on harder materials and larger for softer materials.
The Vickers hardness test is advantageous for its ability to provide fast and simple hardness measurements, making it suitable for many materials where no limitations on the size of the indent exist. The Vickers hardness has traditionally been used for bulk metals and ceramics since the imprints were large enough for direct measurement of diagonals under an optical microscope.