Microstructural evolution and mechanical properties of Inconel 625 superalloy fabricated by pulsed microplasma rapid additive manufacturing

• Published in: Journal of manufacturing processes 2022-05, Vol.77, p.63-74
• Main Authors: Yuan, Xiaojing, Qiu, Hefang, Zeng, Fanqi, Luo, Weipeng, Li, Hao, Wang, Xuping, Guan, Ning, Cui, Fanfan
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Inconel 625 superalloy; Mechanical properties; Pulsed microplasma; Solidification
• ISSN: 1526-6125; 2212-4616
• DOI: 10.1016/j.jmapro.2022.03.008

An innovative pulsed microplasma additive manufacturing (MPAM) system was proposed for fabricating thin-walled Inconel 625 superalloy parts to improve the deposition and heat efficiency of additive manufacturing (AM). During deposition, the heat accumulation from the microplasma was effectively controlled by adjusting the AM current, pulse length of the plasma arc, and scanning speed. Subsequently, the microstructural evolution and mechanical properties were characterized. The Inconel 625 thin-walled parts manufactured using pulsed microplasma rapid AM consisted of γ, γ″, δ, MC, and Laves phases; the latter exhibited a rod-like aggregation distribution. The microhardness ranged from 210.4 HV0.5 to 279 HV0.5, and the tensile strength was 834.77–855.61 MPa. Furthermore, the yield strength was 533.84–543.79 MPa, and the elongation was 31.34%. An Nb-rich phase fraction (31.4%) was observed in the middle region of the as-fabricated sample. Furthermore, the mechanical properties of Inconel 625 superalloy parts produced using pulsed MPAM satisfied the requirements for standard forged Inconel 625 components.