Fig 3. Spherical-tip micro-indentation experimental set-up.

As illustrated in the figure, the sphere induces indentation, smaller than its radius, into the target (Indentation period). After it reaches the maximum depth, it allows the target to relax, with regards to exerted force, in a period of 300 seconds (dwell time of relaxation period). After completion of the process, the sphere is moved away from the target (Retraction period).