Evaluation of Surface by an Ultra-microhardness Tester to Measure Depth of Concavity (2nd Report)

Verification of R-Correction at Indenter Tip and Shallowing Correction of Concavity, Using FEM Simulation

Abstract

The deformation process of a specimen surface during measurement of hardness under 10 mN load is examined by FEM computer simulation. In calculation model a pure aluminum surface is indented by indenters (Vickers type and triangular pyramid), with and without finite tip radius using an ultra-microhardness tester that directly measures the depth of concavity. R-correction at the indenter tip and shallowing correction of concavity, which were proposed in the previous report, are investigated. The results obtained are as follows. (1) Correction for the radius of the indenter tip is effective in evaluating hardness both under test load and after unloading for any indenter. (2) Correction of errors due to "shallowing" of concavity is also effective under 10 mN load.