EFFECT OF LOADING RAMP ON CYCLIC STRESS-STRAIN RESPONSE AND CYCLIC CREEP-BEHAVIOR

The cyclic stress-strain response and cyclic creep behaviour of polycr ystalline copper were shown to depend not only on the length but also on the mode of the start-up ramp in stress-controlled tests at zero me an stress. In tests with a non-zero mean stress, these phenomena are a dditionally affected by the magnitude of the mean stress. There is a s trong correlation between the cyclic creep strain and the saturated pl astic strain amplitude. In the studied region of small amplitude cycli ng, the explanation lies in the response of the one-phase matrix dislo cation structure.