Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

Abstract

Metal additive manufacturing (AM) has unlocked unique opportunities for making complex Ni-based superalloy parts with reduced material waste, development costs, and production lead times. Considering the available AM methods, powder bed fusion (PBF) processes, using either laser or electron beams as high energy sources, have the potential to print complex geometries with a high level of microstructural control. PBF is highly suited for the development of next generation components for the defense, aerospace, and automotive industries. A better understanding of the as-built microstructure evolution during PBF of Ni-based superalloys is important to both industry and academia because of its impacts on mechanical, corrosion, and other technological properties, and, because it determines post-processing heat treatment requirements. The primary focus of this review is to outline the individual phase formations and morphologies in Ni-based superalloys, and their correlation to PBF printing parameters. Given the hierarchal nature of the microstructures formed during PBF, detailed descriptions of the evolution of each microstructural constituent are required to enable microstructure control. Ni-based superalloys microstructures commonly include γ, γ′, γ′′, $$\delta$$ δ , TCP, carbides, nitrides, oxides, and borides, dependent on their composition. A thorough characterization of these phases remains challenging due to the multi-scale microstructural hierarchy alongside with experimental challenges related to imaging secondary phases that are often nanoscale and (semi)-coherent. Hence, a detailed discussion of advanced characterization techniques is the second focus of this review, to enable a more complete understanding of the microstructural evolution in Ni-based superalloys printed using PBF. This is with an expressed goal of directing the research community toward the tools necessary for a thorough investigation of the processing-microstructure-property relationships in PBF Ni-based superalloy parts to enable microstructural engineering.

A systematic review of Inconel 939 alloy parts development via additive manufacturing process

“…However, thermal stresses contributed to the recrystallization of the sample, leading to an equiaxed structure Fig. 15 (d) [ [42] , [43] , [44] , [45] ].

Fig.

…”

Recent Advances in Additive Manufacturing of Soft Magnetic Materials: A Review

“…It is important to carefully consider the specific requirements and operating conditions of the application to select the most suitable soft magnetic material. Factors such as cost, performance, frequency range, and power density warrant careful consideration in this selection process [ 83 , 84 , 85 , 86 ].…”

Tensile and High Cycle Fatigue Performance at Room and Elevated Temperatures of Laser Powder Bed Fusion Manufactured Hastelloy X

“…Laser powder bed fusion (LPBF) offers an advanced additive manufacturing (AM) approach that enables integrated fabrication of complex structural parts by sequentially melting metal-powder layers. This technique ensures superior precision in forming with reduced processing timeframes, making it highly suitable for the efficient manufacture of aeroengine and gas-turbine components [8,9].…”