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A new class of defects has been recently discovered,which are regarded double oxide film defects.In this study, a number of Ni-based vacuum-cast test bars were investigated. The fractures in the broken test barswere observed by Scanning Electron Microscopy (SEM). Energy Dispersive Spectroscopy (EDS), as well asWavelength Dispersive Spectroscopy (WDS) were used to characterize the chemical elements of the fracture’ssurface. Observation by SEM revealed the presence of inclusions identified as films that appeared to have initiatedthe growth of carbides. This study has added to the evidence that oxide film defects do exist in Ni-based super-alloyin certain vacuum casting conditions. It provides a reference for researchers’ further study on the defects, andprovides a possible direction for researchers to improve casting technology so as to remove these defects.
A new class of defects has been recently discovered, which are considered double oxide film defects. In this study, a number of Ni-based vacuum-cast test bars were investigated. The fractures in the broken test barswere observed by Scanning Electron Microscopy (SEM Energy Dispersive Spectroscopy (EDS), as well as Wavelength Dispersive Spectroscopy (WDS) were used to characterize the chemical elements of the fracture’ssurface. Observation by SEM revealed the presence of inclusions identified as films that had toasted the growth of carbides. This study has added to the evidence that oxide film defects do exist in Ni-based super-alloyin certain vacuum casting conditions. It provides a reference for researchers’ further study on the defects, andprovides a possible direction for researchers to improve casting technology so as to remove these defects.