Tip Shape Effect on Hot Nanoindentation Hardness and Modulus Measurements

This paper focuses on tip shape and degradation of diamond indenters upon high temperature nanoindentation tests. Accurate indenter area functions (IAFs) are essential for the correct measurement of mechanical properties by instrumented indentation techniques (LIT), particularly during high temperature (TIT) nanoindentation. However, being a relatively new technique, sufficient information is lacking. This paper examines the shape and degradation of a Berkovich indenter tip after HT nanoindentation testing of 1 mm-thick SiC and Al thin films at room temperature and at T=100 degrees C, 200 degrees C and 300 degrees C. IAFs were determined by the reference method and by atomic force microscopy (AFM, with the latter giving higher contact areas, although tip defect values extracted from both methods were in good agreement. Examination of the tip by AFM after HT nanoindentation on SiC reveals a blunt tip and the need for a new ME The work emphasizes the importance of carrying out indenter tip shape calibrations on a regular basis, especially when indenting and scanning hard samples and metals that readily oxidise at T>200 degrees C, where the tip gets easily contaminated