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Effects of vacuum on gas content, oxide inclusions and mechanical properties of Ni-based superalloy using electron-beam button and synchrotron diffraction

DOI: 10.1016/j.matdes.2021.109861 DOI Help

Authors: Liang Zheng (Beijing Institute of Aeronautical Materials) , Guoqing Zhang (Beijing Institute of Aeronautical Materials) , Michael Gorley (Culham Centre for Fusion Energy) , Tung Lik Lee (ISIS Neutron Source) , Zhou Li (Beijing Institute of Aeronautical Materials) , Chengbo Xiao (Beijing Institute of Aeronautical Materials) , Chiu C. Tang (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Materials & Design , VOL 22

State: Published (Approved)
Published: June 2021
Diamond Proposal Number(s): 10597

Open Access Open Access

Abstract: The effects of vacuum induction melting (VIM) vacuum (<1 Pa to 100Pa) on gas content, oxide inclusions and mechanical properties of Ni-based superalloy K4648 has been investigated by electron beam (EB) button experiment under high vacuum (10-3 Pa) and high resolution synchrotron X-ray powder diffraction (SXPD). The results indicated that VIM remelting vacuum drop has obvious effect on the existing form of trace oxygen. The total amount of oxygen did not increase significantly but a dramatic increase in the amount of oxide inclusions by 1-2 orders of magnitude was found. The inclusions are mainly oxides including Al2O3, Cr2O3, Ni(Al,Cr)2O4 and complex oxides or sulfides. Remelting under 100-110Pa has no significant effect on mechanical properties such as stress rupture life and tensile strength but decreased ductility obviously. In comparison to the normal vacuum counterpart, the tensile elongation and impact ductility of the alloy remelted under lower vacuum level decreased by 67% and 40%, respectively. This study reveals the relationship between the vacuum level and mechanical properties of superalloys and highlights the trace amount of oxide inclusions which should be considered as one of the key issues for the cleanliness of superalloys apart from the typical measurement of the gas content only.

Journal Keywords: superalloy K4648; electron beam (EB) button; synchrotron X-ray powder diffraction (SXPD); oxygen content; ductility; inclusion

Diamond Keywords: Alloys

Subject Areas: Materials, Engineering

Instruments: I11-High Resolution Powder Diffraction

Added On: 02/06/2021 08:25


Discipline Tags:

Materials Engineering & Processes Aerospace Materials Science Engineering & Technology Metallurgy

Technical Tags:

Diffraction X-ray Powder Diffraction