| Summary: | 碩士 === 國立清華大學 === 材料科學工程學系 === 90 === In this thesis, mechanical properties of alloys and thin films have been studied by nanoindentation. For WC-Co alloys, WC / 6.5% Co with an average grain size of 2.5 μm and WC / 10% Co with an average grain size of 0.4 μm are investigated. The results reveal variation in hardness values of finer grained WC-Co alloys due to indentations between the binder phase and the hard phase. For a titanium nitride film on silicon, which represents a system of a hard film on a soft substrate, the measured hardness and Young’s modulus remains a value of 30 GPa and 306 GPa respectively until the indentation depth is approximately 1/3 of the film thickness and starts to decrease as the indentation depth increases. For a titanium film on sapphire, which represents a system of a soft film on a hard substrate, the measured hardness maintains a value of 7 GPa and Young’s modulus increases with increasing the indentation depth. Our results are also compared with theoretical values from Hertz mechanics and Sneddon mechanics.
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