Fatigue Testing of Thin Metallic Foils and Wires

Metal foils and wires are used in a wide variety of applications from radiators to Micro-Electro-Mechanical Systems (MEMS) to electronics to optics to food preparation. Knowing how long the foil and wire will survive the loading associated with the specifi c application is important in predicting the success of the product itself. Knowing the fatigue life of the material in a traditional ASTM specimen geometry does not necessarily mean you know the fatigue life of the material as applied in the fi nal product. Foils and wires may be only a few molecules thick which makes standard manufacturing defects a source of crack initiation and failure. The process used to manufacture a thin foil or wire may alter the mechanical properties of the metal and the chances of damage during normal handling and production is much higher than for thicker materials. These effects can make the foil and wire prone to fatigue damage at stress levels dramatically lower than the commonly accepted material fatigue life thresholds.