Effect of elevated temperature on high-cycle and very-high-cycle fatigue properties of Ni-based superalloy manufactured by selective laser melting.

• The interior fatigue failure with longer life is greatly promoted at 650 °C. • The interior cracks are mainly nucleated from the facets associated with grain structure. • The interior crack nucleation and growth mechanisms at T = 25 °C & 650 °C are elucidated. • A microstructure-based crack nucleation life prediction model is proposed. Axial loading tests with stress ratios of −1 and 0.1 at 25 °C and 650 °C were performed to investigate the effect of elevated temperature on high-cycle and very-high-cycle fatigue properties of a Ni-based superalloy manufactured by selective laser melting. Interior fatigue failure with longer life is greatly promoted at elevated temperature, which is induced from the crystallographic facets associated with grain structure. By means of electron-backscattered diffraction and stress intensity factor evaluation, the interior failure mechanisms are elucidated. Based on the proposed microstructure-based crack nucleation life model, a good agreement between the predicted and experimental results is obtained. [ABSTRACT FROM AUTHOR]