Studies of Vickers indentation curves of elastoplastic materials give information about the relationship between plasticity and elasticity. We have built equipment which gives a record of the applied depression depth, h, as a function of the carried load, P (range, 0.5 to 20 N).

Investigation of the Vickers indentation curves, P(h), during loading and unloading and microscopic observations shows that the phenomena occurring during indentation are complex. We first discuss the loading curve. A comparison with a theoretical analysis is made. Young's modulus, E, and the Vickers indentation pressure during loading can be calculated from the unloading and loading curves. The meaning of the different characteristic parameters of the depth-load graphs is debated. Their correlation with optical measurements of the remanent Vickers indentation is proposed.