DETERMINATION OF THE HARDNESS AND ELASTIC-MODULUS FROM CONTINUOUS VICKERS INDENTATION TESTING

Continuous Vickers (H-V) indentation tests were performed on different materials (ion crystals, metals, ceramics, silica glass and plastic). Load-indentation depth curves were taken during the loading as well a s during the unloading period by a computer controlled hydraulic mecha nical testing machine (MTS 810). The indentation work measured both th e loading and the unloading periods, and these were used for the evalu ation of parameters characterizing the materials. It was found empiric ally that there were linear connections between the maximum load to th e power 3/2 and the indentation work. These connections were used to r elate the conventional hardness number, H-V, and Young's modulus, E,wi th the work performed during loading and unloading. This work can be d etermined with great accuracy from the measurements. The values of the Young's modulus and the Vickers hardness determined this way agree we ll with those obtained by conventional methods. On the basis of contin uous indentation tests, materials can be easily classified into the is omechanical groups introduced by Ash by. For this classification the H -V/E ratio is general ly used. As a substitute for H-V/E another param eter is recommended which can be determined easily from a single measu rement.