Wear Mechanisms at High Temperatures. Part 3: Changes of the Wear Mechanism in the Continuous Impact Abrasion Test with Increasing Testing Temperature

The aim of the present work is to find the critical temperature for different alloys and show how the wear mechanisms change depending on different microstructure once the critical temperature is exceeded. It was found that below 800 A degrees C some materials change their wear behaviour gradually with temperature, and some materials have a critical temperature above which the behaviour changes significantly. It was found that the gradual changes seem to be correlated to the hot hardness of the material. When the changes become significant, it is often due to a change in the wear mechanism, as, e.g. when the matrix gets too soft to support the carbides, and thus breaking of the carbides becomes the dominant wear mechanism or by reaching a critical oxidation temperature above which oxidation causes the material to fail.