Title: Nanoindentation studies in NiTi films deposited on Si wafer

Authors: A. Kumar, Sudhir Kumar Sharma, Samir V. Kamat, S. Mohan

Addresses: Defence Metallurgical Research Laboratory, Hyderabad, 500058, India. ' Department of Instrumentation, Indian Institute of Science, Bangalore 560012, India. ' Defence Metallurgical Research Laboratory, Hyderabad 500058, India. ' Department of Instrumentation, Indian Institute of Science, Bangalore 560012, India

Abstract: Nanoindentation tests were carried out at different locations in a Ti rich NiTi film deposited on a 3|| silicon wafer by dc magnetron sputtering. The purpose of doing nanoindentation at different locations was to check the uniformity of the sample with respect to its mechanical behaviour and shape memory effect. The results showed that elastic modulus and hardness measured by nanoindentation was similar at different locations in the 3|| wafer. Nanoindentation coupled with depth profiling of residual indents using AFM also showed that the extent of shape memory recovery obtained by heating the film above its martensite to austenite phase transformation temperature was also similar at different locations in the 3|| wafer. However, the measured recovery ratio was lower than that predicted from theoretical calculations for indents made using Berkovich indenter. The results showed that the deposition process resulted in a NiTi film with uniform composition, mechanical properties and shape memory behaviour.

Keywords: nickel titanium film; nanoindentation; shape memory effect; recovery ratio; nanotechnology; silicon wafers; elastic modulus; hardness; deposition process.

DOI: 10.1504/IJSURFSE.2011.039991

International Journal of Surface Science and Engineering, 2011 Vol.5 No.1, pp.63 - 74

Available online: 09 May 2011 *

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