Tensile Testing of Thin Films: Tensile Testing, Digital Image Correlation and Feaschemes for Tensile Testing of Aluminum Thin Films Onkaptonâ® Substrates

The process of implementing thin film technologybrings forth the need for characterization of theirmechanical properties with increasing accuracy. Design and performance parameters for a micro-tensiletest apparatus capable of applying a tensile load ofup to 20N with a force and displacement resolution of~1 mN and ±0.3 µm respectively have been presented. The device is well suited for conductingmicro-tensile testing on a variety of specimens withhigh aspect ratios. The apparatus was used to measureYoung's modulus of 1 µm thick Al films deposited onKapton® polyimide substrates. Average value ofE(Aluminum) was found to be around 30±5 GPa. Use ofthe testing scheme employed has been validated usinganalytical and finite element methods. Use of DigitalImage Correlation as a strain measurement tool hasalso been investigated. The device was mounted on anoptical microscope for capturing digital images ofthe specimen undergoing strain. Results show thatcoupled with appropriate software, the method cansignificantly help reduce data collection andanalysis burden.