Hardness Measurement: Invisible to the Human Eye

Material property analysis and hardness measurement provide a broad spectrum of data to a wide variety of markets. Traditionally hardness has been defined as the resistance of a material to permanent penetration by another harder material. Hardness results performing Rockwell, Vickers and Brinell tests are determined after the test force has been removed. Any effect of elastic deformation under the indenter is therefore ignored.

Instruments testing hardness under load by continuously monitoring a complete cycle of increase and removal of test force obtain results that are equivalent to traditional hardness values. In addition, these instruments offer the capability to record additional material properties such as the indentation modulus and elastic and plastic hardness properties. All materials parameters determined from the force/indentation depth set are described and defined in the international standard, DIN EN ISO 14577-1-

Instrumented indentation test for hardness and materials parameters. All of these values can be obtained in one automated measurement by evaluating hardness vs. load, hardness vs. indentation depth and indentation depth vs. load curves. The method also provides information regarding creep and elastic recovery properties of the specimen.