The high-cycle fatigue properties of selective laser melted Inconel 718 at room and elevated temperatures

Aero-engine turbine disk is always subjected to cyclic loading at room and elevated temperatures. Therefore, as one of the typical high-temperature materials, selective laser melted Inconel 718 superalloy was chosen to perform high-cycle fatigue tests at 25 degrees C, 450 degrees C and 650 degrees C and investigate the effect of temperature on fatigue damage mechanism. The locations of fatigue crack initiation are surface and subsurface defects at room temperature, and become subsurface and internal facets at elevated temperatures. An analyzed stress intensity factor and El-Haddad model were performed to assess the effect of defects on fatigue performance at room temperature. By means of electron back scattered diffraction, the fatigue damage mechanisms at elevated temperatures were elucidated. Based on the general relationship between fatigue and tensile strengths of metallic materials, an accurately quantitative relationship among fatigue strength and temperature was proposed.

Automated summary

The study conducted high-cycle fatigue tests on selective laser melted Inconel 718 superalloy at different temperatures, revealing a shift in fatigue damage mechanisms at elevated temperatures.