Ermittlung der Eindringhärte keramischer Verbundwerkstoffe Determination of the indentation hardness of ceramic matrix composites

Kurzfassung

The article introduces a test method that allows the measurement of the indentation hardness of ceramic composites (CMC). CMCs are anisotropic materials consisting of high-strength ceramic fibres in a ceramic matrix. Knowledge of the hardness of CMCs is relevant in practice in order to be able to classify their machinability and wear resistance. The existing test standards for hardness testing of monolithic ceramics or hard metals are not applicable due to the highly varying properties of the CMCs at the micro level. This article shows that instrumented indentation using large diamond spheres as indenters is a suitable method for hardness testing of CMCs. Test conditions (specimen preparation, indenter size, indentation forces) are described with which CMCs of different hardness and structure can be tested. The ceramic composites studied showed large differences in hardness – the measured indentation hardness ranged from 160 MPa to 4300 MPa