The mechanical behavior of conductors exposed to short-duration thermal loading

The current-carrying conductors in an electromagnetic (EM) launcher are exposed to high thermal loads that last for a few milliseconds. In some instances, the temperature increases range up to the melting point of the materials. Even though the equilibrium and creep behavior of materials at high temperature at long time scales is well characterized, such characterization is generally not available for thermal loads lasting for very short durations. Here, we study the mechanical properties, such as elastic modulus and yield strength, of commonly used conductors such as aluminum and copper alloys under millisecond-duration thermal loads. A pulser circuit is designed and used in conjunction with a tensile-testing machine to study property degradation concurrent with and subsequent to the application of the thermal load at different strain rates. The results of our study shall be used for generating constitutive descriptions of material behavior and in designing various components of the EM launchers.