Small-span bending test for determination of elastic-plastic properties of ultrathin Pt wires

A mechanical testing methodology for determination of elastic-plastic properties of very thin metallic wires using small-span bending under lateral load is described. Sufficient strain is locally developed in the tested section of wire by unsymmetrical bending with two opposite probes where one end of the wire is fixed on a substrate with rigid joint by Joule heat welding. From the load-displacement relationships obtained experimentally, Young’s modulus is determined by analytical formulation. Moreover, yield stress and hardening modulus of the wire are identified using an optimization strategy with finite-element analyses. The thin Pt wires with a nominal diameter of about 625 nm are examined by the testing scheme and the wires are found to have higher yield stress compared to bulk Pt.