SINGLE AND DUPLEX CREEP TESTS AT INTERMEDIATE TEMPERATURES ON NI3AL

Creep tests and parallel transmission electron microscopy (TEM) studie s on Ni3Al in the intermediate temperature regime (where strength is i ncreasing with temperature) are described. Under certain circumstances inverse creep is observed. Lower stress and higher temperature both i nhibit the transition to cube cross-slip. Pretesting at constant strai n rate can both increase or decrease the subsequent creep rate, depend ing on the temperature of the pretest. Pre-creep testing also influenc es subsequent constant strain rate deformation. All of these observati ons are rationalised in terms of the dislocation geometry. (C) 1997 El sevier Science S.A.