Stress relaxation research is very valuable as it provides information on how materials relieve stress under a constant strain. In... Show moreStress relaxation research is very valuable as it provides information on how materials relieve stress under a constant strain. In applications where parts are submitted to a constant deformation, it is important to know that regions containing notches or stress concentrations will be able to relax enough to avoid the formation of cracks during operations. In this study, the stress relaxation behaviors of experimental Ni-base superalloy RRHT5 and Pyrowear 53 steel alloy were investigated. Tests were conducted under different conditions, varying temperature, initial strain, and grain size to explore the influence of each of these factors. The stress relaxation test data was used to calculate apparent activation volumes which can be correlated with plastic deformation mechanisms governing the stress relaxation. Understanding these mechanisms and identifying how specific factors influence them is essential to further control and optimize the design and processing of materials to obtain the best properties. Depending on the test conditions, the stress relaxation underwent one or two stages dominated by different mechanisms. These governing mechanisms were considered to be either dislocation-dislocation interactions, dislocation rearrangement, dislocations spreading from localized slip bands or dislocation-precipitate interactions. Show less
