Rapid Characterization of Cyclic Response of Small-Volume Metal Samples Using Spherical Microindentation Stress-Strain

The cyclic stress-strain response of a material provides insight into fatigue properties that may limit the performance of fracture-critical rotating components in gas turbine engines. Historically, conventional cyclic / fatigue is a costly property to assess because of the volume of material required for test coupons and also the time to run each test. Therefore, a critical need exists for the development of novel experimental approaches that can rapidly evaluate the relative changes in cyclic response as a function of alloy chemistry and thermo-mechanical processing history. This becomes especially critical in the materials development efforts, which require systematic exploration of a large materials space. In this work, we present a novel approach using spherical microindentation to deduce stress-strain responses and a cyclic stress-strain curve for Ti-6Al-4V. The results show promise for obtaining reliable, high-throughput, quantitative assessments of the cyclic response.