Determination of material properties and failure using in-situ thermo-mechanical probe

Abstract : A metallic in-situ stress sensor is modified to address electrical polarization and thus to locally heat this sensor by Joule effect. By coupling SEM electrical nano-probing with analytical modeling and multiphysics Finite Element Method (FEM), the thermo-mechanical properties are identified. As a result, a tensile stress state of 190 MPa, coefficient of thermal expansion of 22.5×10-6 K-1 and thermal conductivity of 190 W/(K·m) are identified in the aluminum thin film in agreement with literature. Moreover, high current induces irreversible deformation and breaking. Using multiphysics FE model with identified thermo-mechanical properties, the failure of the sensor under electrical solicitation is investigated. The evolution of local temperature and mechanical deformation on different sensor designs allows the determination of the breaking location and condition.