ABSTRACT
Depth-sensing indentation is usually used for the measurement of the near-surface properties of materials. In depth-sensing indentation testing, the area of contact is determined by first measuring the depth of penetration of the indenter into the specimen surface. The case of a pyramidal indenter can be conveniently treated as that occurring with an axis-symmetric cone whose angle provides the same area-to-depth ratio. In nano-indentation testing, the depth of penetration beneath the specimen surface is measured as the load is applied to the indenter. In theory, the load-displacement curve obtained in depth-sensing indentation tests begins at zero load and zero depth. During an indentation test, application of load to the indenter results in a reaction force applied to the instrument frame which causes it to deflect.
