Influences on Microstructure of DZ98M Composition of the Alloy by Rapid Solidification

Abstract:

In this paper a Ni-based superalloyalloy was fabricated by laser additive manufacturing technology(LEN98M) and by trainditional directional solidification (DZ98M), respectively. The solidification morphology, microstructures, elements segregation are systematically investigated by using optical microscope(OM), scanning electron microscope(SEM), energy dispersive spectroscopy(EDS), X-ray diffraction(XRD), electron microprobe(EPMA), differential thermal analysis(DTA). The results show that the primary dendrite arm spacing of the LEN98M alloy is 70 μm and reduced as 1/5 of the DZ98M alloy. There is a serious segregation of alloying elements in the range of dendrite scale. The morphology of γ? phase are irregular and no precipitation of carbides observed in as-casted LEN98M alloy. There are smaller γ/γ? eutectic dispersed in interdendritic regions.