Single and duplex creep tests at intermediate temperatures on Ni3Al

Creep tests and parallel transmission electron microscopy (TEM) studies on Ni3Al in the intermediate temperature regime (where strength is increasing with temperature) are described. Under certain circumstances inverse creep is observed. Lower stress and higher temperature both inhibit the transition to cube cross-slip. Pretesting at constant strain rate can both increase or decrease the subsequent creep rate, depending on the temperature of the pretest. Pre-creep testing also influences subsequent constant strain rate deformation. All of these observations are rationalised in terms of the dislocation geometry.