Development of a New Testing Procedure for Performing Tensile Tests on Specimens with Sub-Millimetre Dimensions

A new method to conduct tensile tests with specimens ranging from a few millimetres down to 100 mu m is presented. The tensile specimens are fabricated using a newly developed water-cooled circular grinding process that guarantees a high-accuracy geometry by keeping the fabrication-related material change to a minimum. Furthermore, the grinding tool is equipped with a mechanical polishing unit to make well-polished surfaces. Besides the specimen fabrication, the test setup is modified to allow a specimen related displacement measurement. This image-based system does not require any additional specimen markings and enables the evaluation of true stress, true strain, and the reduction in area. The whole method is successfully demonstrated for different types of metals ranging from ductile nickel to very brittle tungsten. In addition to the quality of the tensile test in this specimen size range, another advantage is the enormous reduced time for specimen fabrication and testing.