High-temperature mechanical properties of nickel-based superalloys manufactured by additive manufacturing

Mechanical behaviour of Haynes 230 and Inconel 625 manufactured by selective laser melting (SLM) has been experimentally investigated in 870 o C. Significant embrittlement of SLM Inconel 625 was found, accompanied by hardening behaviour during the test. Moreover, due to inhomogeneous grain deformation, the hardness dispersion of the two SLM alloys increased significantly. Employing a systematic research with scanning electron microscopy and energy-dispersive spectrometer, intergranular cracking of two SLM alloys can be observed from the surface cracks and fracture appearances, respectively. In addition, carbides along grain boundaries of the two nickel-based superalloys were found and affected the strength of the grain boundary at 870 o C. Therefore, it resulted in different fracture mechanisms.