Magnetic and electric bulge-test instrument for the determination of coupling mechanical properties of functional free-standing films and flexible electronics

For the first time a novel multi-field bulge-test instrument which enables measurements of the biaxial mechanical properties and electro-magnetic- mechanical coupling effect of free-standing films in external magnetic/electric fields was proposed. The oil pressure was designed with two ranges, 0-1 MPa for elastic small deformation and 0-7 MPa for plastic/damage large deformation. A magnetic field that was horizontal and uniform in the film plane was supplied by a hollow cylindrical magnet. The magnitude could be changed from 0 to 10000 Oe by adjusting the position of the testing film. Meanwhile, an electric field applied on the film was provided by a voltage source (Maximum voltage: 1000 V; Maximum current: 1 A). Various signals related to deformation, mechanical loading, magnetic field, and electric field could be measured simultaneously without mutual interference, which was confirmed by the coincidence of the measured P-H curves for titanium (Ti)/nickel (Ni) specimens with/without external fields. A hardening phenomenon under magnetic/electric fields was observed for Ni and lead zirconate titanate specimens. The multi-field bulge-test instrument will provide a powerful research tool to study the deformation mechanism of functional films and flexible electronics in the coupling field.