电子束选区熔化(SEBM)增材制造高温合金研究进展

Superalloys are widely used in hot components of aero-engines, mainly due to their good oxidation/corrosion resistance and outstanding mechanical properties. Beam-based additive manufacturing (AM) technologies, particularly the laser and electron beam melting processes, exhibit great potential in producing superalloy components with complex geometries. It combines the advantages of both high flexibility and cost-effectiveness. Besides, the AM superalloys usually have a comparably higher tensile strength than the conventional cast, as a result of the yielded refined microstructure. However, with the increase of Al and Ti content, the superalloys with a higher volume fraction of γ' phase demonstrate high crack sensitivity. This brings challenges of applying AM to the aero industry. Compared with selective laser melting (SLM), the powder bed preheating featured by selective electron beam melting (SEBM) helps alleviating the thermal stress and the resultant hot cracks. In this review, the latest developments of Ni and Co-based superalloys fabricated by SEBM are reviewed. The SEBM processing parameters, microstructure and mechanical properties of weldable and non-weldable superalloys are compared and evaluated. Finally, several possible research directions are also suggested.