A NOVEL SMALL-SCALE BEND GEOMETRY CREEP TEST TO EVALUATE DEFORMATION AND CAVITATION DAMAGE IN POLYCRYSTALLINE AND BI CRYSTAL COPPER
Elsiddig ElmukashfiGrand Ballroom B
Understanding the mechanisms of creep deformation and damage (cavitation) in engineering components materials is important, but despite the significant research that has been conducted over the past 50 years, there is still a lack of understanding of the microstructural processes that influence and control the development of damage. To provide further insights into this, in the present work a novel small-scale constant load cantilever beam geometry test specimen is used. The materials selected for the tests are polycrystalline and bi-crystals of high purity copper. The copper provides a simple model material for exploring initiation and early growth of creep cavitation and allows comparison with crystal-based model predictions.
In this study, both creep deformation and creep cavitation were measured. For the latter, a range of higher spatial resolution techniques were adopted including scanning electron microscopy, electron backscattered diffraction and focused gallium ion beam serial section milling. Creep cavity number density and size measurements were made using advanced image analysis procedures. Polycrystalline and bi-crystal results are compared, with particular attention given to the role of Schmid factor and misorientation on the initiation and early growth of the creep cavities. These experimental results inform the development of microstructural based models of cavitation.