A two-material miniature specimen test method and the sssociated inverse approach for high temperature applications

A miniature two-material test specimen has been developed for material property characterization. Elastic-plastic and creep damage models have been applied for a semi-analytical model and a finite element (FE) model to simulate the miniature specimen tensile and creep tests on a two-material system. An inverse optimization algorithm has been developed, which can be used to extract the creep properties of the unknown material in the two-material system. Single material miniature specimen tensile tests have been performed for an aluminum alloy at room temperature and 400°C and full stage creep tests have been performed for a P91 steel at 650°C. All the tensile and creep test specimens are brought to fracture failure. The experimental results have been compared to the results from the corresponding results from conventional uniaxial tensile and creep tests on the same materials and under the same test conditions. This miniature specimen testing technique and the developed inverse method have the potential to become a new approach for determining the elastic-plastic and the full-stage creep properties until rupture for a two-material system at high temperature, e.g. a coating-substrate system