The effect of carbon content on the printability and mechanical properties of Ni-based superalloy in laser additive manufacturing

The role of trace elements in additively manufactured superalloys remains a subject of ongoing discussion. It is crucial to investigate the effective mechanism and control range of trace elements in superalloys for additive manufacturing (AM). In this study, C was focused on and investigated to analysis the effect of C content on the printability and mechanical properties of a dedicated additive manufacturing superalloy. The results indicated that the cracking susceptibility of the alloy firstly increased and then decreased when the C content increased within a certain range (0–0.092 wt.%). The alteration of C content affected the precipitation temperature and size of γ′ precipitates, and changed the freezing range of the alloy. As a result, a nonlinear relationship was observed between cracking susceptibility and C content. Furthermore, under thermal cycling, the gradually grown carbides filled microporosity and reduced the porosity of the alloy. The dispersion of carbide particles could effectively prevent dislocation movement and enhanced the strength of the alloy. These findings clarify the influence of C content within a certain range on the printability and mechanical properties of the alloy and provide guidance for the regulation of C content in subsequent alloy design.