High temperature nanoscale mechanical property measurements

Abstract

A depth sensing indentation instrument widely used for measuring the small scale mechanical properties of thin films and surfaces has been modified for operation at elevated temperatures. The essential feature permitting this development is the vertical orientation of the specimen, which allows the heated zone to be placed above the high sensitivity displacement transducer. In the present work, small scale hardness and elastic modulus measurements were performed on glass, gold, and single crystal silicon at room temperature and 200°C. The results show that at 200°C the hardness and elastic modulus of soda lime glass and gold are lower than at room temperature, as anticipated. In contrast, indentation testing of Si(100) at 200°C produced a similar hardness value to that obtained at room temperature, although the modulus was again reduced, from 140·3 to 66·0 GPa. In addition, the well known ‘pop out’ event, which is observed during unloading of a silicon indentation at room temperature, disappeared at 200°C.