Published Paper Details:

In micro-indentation testing for several types of materials, the indentation size effect (ISE) was noted for a comparatively greater range of applied test loads. Heat-treated plain carbon steels, copper, aluminium, and tool steels were the samples used in this investigation. The analysis made use of a micro-hardness tester with loads ranging from 0.49N to 9.8N. The modified proportional specimen resistance model (MPSR i.e. P = P0+a1 d1+ a2 d2), where P0 accounts for the residual surface stresses generated during the sample preparation process, provided better correlation between literature-cited load-independent hardness values and the measured values among the existing models that relate the indentation load and indentation length. Regardless of the loads applied, the investigation produced the precise hardness values for all the materials. Surface strains or any brittle structures at the surfaces can occasionally cause inconsistencies in the hardness readings.