In order to solve the difficulties in measuring local stress and strain

the parameters of Chaboche viscoplastic constitutive equations for powder metallurgy super alloy FGH97 at 550℃

which were obtained based on the experiments of material mechanical properties

were used in the elastoplastic FEM (finite element method) analysis of notched specimens subjected to tensile and cyclic loading.The results show that:(1) plastic stress/strain state at notch root is obviously different from elastic one.With the increase of stress

location of maximum stress moves inside.(2) Under cyclic loading

with the increase of cyclic number

the stress and strain range along symmetric path at notch root changes little.Mean stress relaxation occured in the plastic zone at notch root gradually turns to be stable

and it also leads to different cyclic stress ratios compared with the applied load.(3) The plastic zone at notch root gradually increases

but the increasing range gradually decreases.The research result can provide support to further analysis of influencing factors which affect fatigue life of FGH97 notched specimens.