Temperature Indentation Testing

At present, the majority of indentation testing is performed at room temperature and this is often sufficient for many applications. However, there is an increasing need to investigate the surface mechanical properties of certain materials at or near their in-service temperatures. Previous development of high-temperature hardness testing has shown that the hardness of materials tends to decrease with increasing temperature. In addition, high temperature tests have been used to investigate creep in ceramic materials, cracking of sapphire and slip lines and dislocations in MoSi2. There are several factors which require consideration when making high temperature indentation measurements: Thermal drift effects: it is important to enclose the sample as much as possible in order to minimise thermal gradients; Indenter: the properties of the indenter material may change significantly during heating and the mounting may be affected by loading at high temperatures; Heat transfer between sample and indenter needs to be controlled to prevent large errors in the depth measurement