Hardness testing system using multiple depth measurements and related methods

An apparatus comprising:

• a holder to support an indenter with respect to a sample of material;
• a depth sensor;
• and
• a controller to execute instructions for performing operations comprising
• controlling the holder to apply a first force on the sample with the indenter and determining a first depth of the indenter based on first data generated by the depth sensor;
• controlling the holder to move the indenter from the first depth to a second depth greater than the first depth, the second depth being a predetermined depth;
• after the indenter is moved to the second depth, controlling the holder to apply the first force on the sample with the indenter and determining a third depth of the indenter based on second data generated by the depth sensor;
• and
• determining a value indicative of hardness of the sample based on a difference between the first depth and the third depth.