Analysis and evaluation of mechanical descriptors from micro compression tests on spherical samples

Abstract

Within the development of a novel high-throughput method for the discovery of new structural materials, a compression test on spherical micro samples is established as a short-term characterization process. In this study, the experimental investigations regarding the elastic–plastic deformation behavior of microspheres are carried out on the bearing steel X46Cr13 in 10 different heat treatment conditions. Characteristic values, so-called descriptors, can be derived directly from continuously measured force–displacement curves or are normalized by taking the sample geometry into account. In addition to micro compression tests with quasi-static loading, load increase tests are performed, in which a spherical sample is repeatedly loaded and unloaded with progressively increasing loads. Loading and unloading phases and the development of the displacement amplitude of the hysteresis are analyzed. New descriptors of load increase tests are extracted and discussed regarding their statistical significance and validity as descriptor showing a high potential for a fast characterization of the material behavior during cyclic loading. The descriptor-based micro compression test proves to be a robust method and is a promising approach for a fast evaluation of different material conditions.