Mechanical properties of surface layers, thin films or small volumes o
f material can be studied using ultra-microindentation devices, whereb
y the indenter displacement is measured continuously during loading an
d unloading. This approach enables hardness, elastic modulus, yield st
rength and the energy spent on loading or unloading to be determined.
Also other material characteristics can be defined, such as the elasti
city index and the indentation work per unit volume of the permanent i
mpression. Loading and unloading curves may be described by simple pow
er-law functions, which are important for the evaluation of data, but
can also be utilised for modelling of contact loading. Pointed indente
rs (Berkovich, Vickers) deform under conditions of constant strain, wh
ich is advantageous when material properties in a larger range of dept
hs are studied, particularly if these properties change with depth. In
the paper, the determination and use of the above quantities is illus
trated for tests done with Berkovich indenter on steel and glass.