硬質薄膜之奈米壓痕量測與有限元素分析

The investigation of mechanical properties of thin hard coating in the nanoindentation process

鄧芳怡(Fang-Yi Deng)

指導教授 ： 徐澤志 ； 黃正熙

元智大學/工程學院/機械工程學系/碩士(2004年)

摘要

近年來薄膜已廣泛的應用到許多產品上，硬質碳膜除了硬度非常高之外，尚具有非常低的摩擦係數及優越的電絕緣性和超高傳導性、生物相容性、光滑及耐磨耗性等性質，由於具有這些優越特性，使得在機械、電子、半導體等工業之應用日益廣泛。由於薄膜披覆厚度的等級進入微米、奈米等級，其薄膜的性質與塊材(bulk materials)時的性質有所不同，所以本論文使用奈米壓痕(nanoindentation)量測，研究硬質薄膜(hard coating)的機械性質，如：硬度、楊氏係數等，藉由奈米壓痕的量測，可以得到類鑽碳薄膜在承受到某一負載時的負載大小與壓痕深度的曲線圖，進而利用有限元素軟體來模擬壓痕過程。研究成果首先與學者的文獻模擬分析結果相比，來確認模擬模型的正確性；接著利用實驗所得到負載與壓痕深度曲線圖，反推獲得類鑽碳薄膜的應力-應變曲線。

關鍵字

奈米壓痕 ； 機械性質 ； 有限元素分析

並列摘要

The widespread use of thin hard physical vapor deposited (PVD) coatings such as Diamond-like carbon (DLC) in various technical applications necessitates the knowledge of their mechanical properties. In recent years, the nanoindentation experiment becomes a very successful technique to investigate the mechanical properties of thin coating. A very low load is applied on the specimen by using the Berkovich indenters and then the elastic modulus, as well as the hardness, can be determined from the recorded load-displacement curve.

In this work, we used the finite element method to simulate the nanoindentation process. Due to the complexity of the phenomena involved in the indentation process, the finite element program MARC which allows effective modeling of bilinear mechanical property such as the elastic modulus and tangent modulus was applied to simulate the deformation behavior of the material. By comparing the numerical simulations with the results obtained from nanoindentation experiment, it is possible to extract precisely the stress-strain curve of the diamond-like carbon thin films on tungsten carbide substrates and describes the mechanical properties of thin hard coating by using a bilinear model.

並列關鍵字

nanoindentation ； mechanical properties ； finite element analysis

參考文獻

[2] A. C. Fischer-Cripps, Nanoindentation, Mechanical Engineering Series, Springer-Verlag, ISBN 0-387-95394-9, 2002.

[4] Tabor D. The hardness of metals. Oxford: Oxford Univ. Press, 1951.

[5] Sneddon, I.N., “The relaxation between load and penetration in the axisymmetric Bussinesq problem for a punch of arbitrary profile.” International Journal of Engineering Science, 3, pp. 47, 1965.

[6] Doerner, M. and Nix, W.D. “A method for interpreting the data from depth-sensing indentation instruments.” Journal of Materials Research, 1 , pp. 601-609, 1986.

[7] Pharr, G.M. and Oliver, W.C. “Nanoindentation of silver-relations between hardness and dislocation structure.” Journal of Materials Research, 4(1), pp. 94-101, 1989.