Influence of solution temperature and stabilization treatment on the fatigue crack growth feature of GH864 alloy

The crack propagation of GH864 alloy with different solution temperatures and stabilization treatments was studied.The percentages of crack initiation period,propagation period and final fracture period in the whole fatigue failure process were calculated by analyzing the microstructure,fracture morphology and lga-lgN_i/N_f,da/dN-a and da/dN-N curves.The influence of microstructural factors on the percentages of each period was analyzed.The result shows that with increasing solution temperature,the grain size of GH864 alloy enlarges,the crack growth rate decreases,meanwhile the percentage of crack initiation period decreases but the percentage of crack propagation period increases.With the time prolonging and the temperature rising in the stabilization process,the amount of carbides precipitated at grain boundaries increases,thereby the crack propagation rate decreases,but the percentage of crack initiation period is gradually increasing.