Surface Roughness Effect on Microhardness Measurements

Micro-Vickers hardness measurements are essential for evaluating micro-scale material hardness, providing insights into surface properties and material strength. However, many factors can influence the precision of hardness measurements. This study examines the influence of surface roughness on the results of micro-Vickers hardness measurements. A polished stainless steel gage block is used as a test sample. Sample surfaces are textured using different grit sandpapers. The surface texture was analysed using the 3D surface roughness measuring system. A test matrix with eight different test forces ranging from 0.01 to 0.5 kgf was used for micro-Vickers hardness measurements. The measurement results indicated that a small change in the surface roughness impacts the measurement results with a more significant effect when applied test forces are below 0.1 kgf. Obtained surface hardness values increase with surface roughness, accompanied by a rise in the standard deviation of the measurements.