Thickness-Dependent Mechanical Behaviour of Aluminium-Coated Polyethylene Terephthalate (PET) Films

Abstract Mechanical behaviour of aluminium-coated PET films has been investigated through Dynamic Mechanical Analyser. Aluminium is coated on PET substrate by vacuum thermal evaporation method. As thickness of aluminium coating increases from 150 nm to 350 nm, tensile strength decreases from 108.88 MPa to 99.25 MPa. This mechanical behaviour is correlated with microstructure and its evolution with the thickness of aluminium coating. Al-PET film consists of fine globular grains and average grain size increases monotonically with the film thickness. The relative contribution of the grain size to the strength of aluminium thin films is in good agreement with Hall-Patch equation. Keywords: CoatingMechanical behaviourThin filmsYield strength ACKNOWLEDGMENTS One of the authors Sandhya Gupta is thankful to UGC for providing financial assistance during this work. Author would also like to thank Ms. Deepika, Mrs. Rashmi Saxena, and Dr. Dinesh Patidar, Mr. K. S. Rathore, Mr. Vishal Mathur for their help in various ways during the course of this work.