Thermally stable strong texture in additively manufactured cobalt-based superalloys

Abstract

Cobalt-based γ'-strengthened superalloy exhibits tremendous potential in numerous fields, such as power generation equipment and the aerospace industry. The characteristics of laser powder bed fusion technology have aligned well with the demands for superalloy's strong texture or single crystal microstructure. However, the post-heat treatment processes often disrupt the initial microstructure of the as-printed parts due to unavoidable recrystallization. In this study, we obtained a strong <101> texture in an as-printed Co-5Al-14V (at.%) ternary cobalt-based superalloy, which is difficult to achieve in nickel-based superalloys. Intriguingly, this <101> texture remains thermally stable even after aging treatment at a near γ' solvus temperature. Hence, a <101> textured microstructure with an evenly distributed γ'(L12) precipitates was attained, which benefits the improvement of high-temperature creep resistance. The unique microstructure characteristics revealed in this work can be beneficial for the development of cobalt-based superalloys and shed light on the microstructural engineering of other LPBF-manufactured superalloys.