research engineer, Oak Ridge National Laboratory, Oak Ridge, Tenn.
Associate scientist, Aerojet Nuclear Co., Idaho Falls, Idaho
Results of tensile and fully reversed strain-controlled fatigue tests, conducted on three heats of Incone® 718 that had been subjected to different solution annealing and aging treatments, are presented. Tests were conducted at temperatures ranging from 22 to 650°C, with fatigue tests defining behavior over the cyclic range from 102 to 106 cycles to failure. Average best fit equations defining true stress-strain, strain-controlled fatigue, and cyclic stress-strain behavior are given for the two heat treatments characterized. Heat-to-heat variations in the elevated temperature tensile and fatigue behavior were found. Fatigue lifetime was seen to be dependent upon grain size, particularly at lower strain ranges.
Paper ID: JTE10109J