Characterization of mechanical and thermal properties of thin Cu-foils and wires

There is an increasing necessity to record the deformation characteristics of microelements often consisting of freestanding foils and wires due to their increasing demand in engineering applications, where they are being used in the automotive industry, micromachines, special sensors, etc. The data required are either mechanical or thermal such as Young’s moduli, stress–strain values, fatigue and thermal strain data. Due to the size effect these data cannot be taken from macrospecimens, thus special testing procedures were introduced. For the mechanical properties tensile tests were used for the freestanding foils and wires. Laseroptical sensors based on the speckle correlation method were applied to determine non-contacting strain values with high strain resolution. Equipped with a special air furnace mechanical data could be obtained up to 300 8C. For thermal strain measurements a laser speckle based dilatometer (LSBD) was designed. The following materials data are presented and discussed: Thermal expansion data, mechanical and fatigue properties of Cu foils (electrodeposited (ED), rolled and annealed) and wires with varying thickness. A pronounced thickness effect was detected. The applicability and limitations of the testing equipment used are discussed.