Fatigue damage cumulation in brass under variable loading

In the paper there was presented the course of fatigue damage cumulation in specimens made of CuZn37 brass. During the analysis the course of damage cumulation there were used parameters of hysteresis loop and microstructure changes for different levels of fatigue damage, that were registered during the tests. Basing on the analysis of three hysteresis loop parameters (stress amplitude [...], plastic strain amplitude [...] and plastic strain energy \deltaWpl) it has been found that during variable loading the smallest changes are observed for the energy \deltaWpl. Microscopic analysis of brass specimens after various fatigue levels showed that fatigue damage cumulation is also visible in changes taking place both within grains and at their boundaries. These changes include the presence of failures at boundaries of grains and slide banding systems inside of them, which are typical for plastic strain of the material.